PAPERmaking! Vol.9 No.3 2023 by pita.co.uk

PAPERmaking! The e-magazine for the Fibrous Forest Products Sector

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Paper Technology International®

Volume 9 / Number 3 / 2023

PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY TE INTERNATIONAL®

Volume 9, Number 3, 2023

CONTENTS: FEATURE ARTICLES: 1. Corrugated: Creep Performance of Corrugated Fibreboard Boxes. 2. Tissue: Angle of the Perforation Line on Partitioning Efficiency of Toilet Papers. 3. Decarbonisation: Hydrogen, Ammonia, and Methanol as Carbon-Neutral Fuels. 4. Maintenance: Data-driven Predictive Maintenance: a Paper Making Case. 5. Water Treatment: Biomass Fly Ash / Fenton Process for Wastewater Treatment. 6. Pulping: Synergies between Fibrillated Nanocellulose and Hot-Pressing of Papers. 7. Wood Panel: Quantifying the Carbon Stored in Wood Products. 8. Packaging: The Perceived Environmental Friendliness of Product Packaging. 9. Winter Driving: How to Demist your Windscreen in Double Quick Time. 10. Office Productivity: Top Tips to Improve Your Office’s Productivity. 11. Computing: Windows 10 Tips and Tricks that Help you get Stuff Done Faster. 12. Thinking Skills: How to Think Clearly: 7 Tips for Success. SUPPLIERS NEWS SECTION: News / Products / Services: Section 1 – PITA Corporate Members: ABB / ARCHROMA / PILZ / VALMET Section 2 – PITA Non-Corporate Members PCF MAINTENANCE / VOITH Section 3 – NON-PITA SUPPLIER MEMBERS GTEC / INVENT Advertisers: ABB & PCF MAINTENANCE DATA COMPILATION: Events: PITA Courses & International Conferences / Exhibitions Installations: Overview of equipment orders and installations between June and Oct. Research Articles: Recent peer-reviewed articles from the technical paper press. Technical Abstracts: Recent peer-reviewed articles from the general scientific press. The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International® and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 1

Contents

PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY TE INTERNATIONAL®

Volume 9, Number 3, 2023

Influence of different box preparations on creep performance of corrugated fibreboard boxes subject to constant and cycling relative humidity environments ELI M. GRAY-STUART1, KELLY WADE2, GABE P. REDDING 1, KATE PARKER 2 & JOHN E. BRONLUND 1 To understand the effect of load and relative humidity (RH) on box creep in cool storage conditions, standard tests are performed. However, these test conditions are oversimplified compared with actual shipping conditions. Our aim is to develop test conditions that more closely mimic those encountered during refrigerated conditions to investigate their influence on creep performance and box lifetime. We compared three box preparations: (i) empty boxes used as a control, (ii) filled boxes, and (iii) boxes with only two side panels exposed to the atmosphere. A controlled environment test facility was used to subject sets of 24 boxes to 30% of their ultimate failure load under different cyclic and constant relative humidity conditions. Results indicate that filled boxes had substantially reduced performance in terms of secondary creep rate and lifetime. The fill in the box contributed to out-of-plane displacement of the side panels which manifested earlier than in the control, resulting in a higher creep rate. Boxes with only two exposed panels had lower moisture uptake and performed substantially better than the control. These findings demonstrate how creep performance and box lifetime depend on the box conditions including fill and the area of the box that is exposed for moisture transfer. Alternative box preparations which mimic supply chain conditions are worthy of investigation in creep analysis as they will help predict more accurately box performance in the cold supply chain. Contact information: 1 Department of Chemical and Bioprocess Engineering, Massey University, Palmerston North, New Zealand 2 SCION, Rotorua, New Zealand Packag Technol Sci. 2022;35:497–504. https://onlinelibrary.wiley.com/doi/10.1002/pts.2646 Creative Commons NonCommercial-NoDerivs License,

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International® and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 9

Article 1 – Corrugated Fibreboard & Creep

Received: 26 May 2020

Revised: 1 February 2022

Accepted: 20 February 2022

DOI: 10.1002/pts.2646

RESEARCH ARTICLE

Influence of different box preparations on creep performance of corrugated fibreboard boxes subject to constant and cycling relative humidity environments Eli M. Gray-Stuart1 John E. Bronlund1

1 Department of Chemical and Bioprocess Engineering, Massey University, Palmerston North, New Zealand 2

SCION, Rotorua, New Zealand

Correspondence E. M. Gray-Stuart, Department of Chemical and Bioprocess Engineering, Massey University, Palmerston North 4474, New Zealand. Email: e.m.gray-stuart@massey.ac.nz

Kelly Wade2 |

Gabe P. Redding1

Kate Parker2 |

Abstract To understand the effect of load and relative humidity (RH) on box creep in cool storage conditions, standard tests are performed. However, these test conditions are oversimplified compared with actual shipping conditions. Our aim is to develop test conditions that more closely mimic those encountered during refrigerated conditions to investigate their influence on creep performance and box lifetime. We compared three box preparations: (i) empty boxes used as a control, (ii) filled boxes, and (iii) boxes with only two side panels exposed to the atmosphere. A controlled envi-

Funding information Massey University

ronment test facility was used to subject sets of 24 boxes to 30% of their ultimate failure load under different cyclic and constant relative humidity conditions. Results indicate that filled boxes had substantially reduced performance in terms of secondary creep rate and lifetime. The fill in the box contributed to out-of-plane displacement of the side panels which manifested earlier than in the control, resulting in a higher creep rate. Boxes with only two exposed panels had lower moisture uptake and performed substantially better than the control. These findings demonstrate how creep performance and box lifetime depend on the box conditions including fill and the area of the box that is exposed for moisture transfer. Alternative box preparations which mimic supply chain conditions are worthy of investigation in creep analysis as they will help predict more accurately box performance in the cold supply chain.

I N T RO DU C T I O N

they can also fail due to compressive creep (Figure 1) when a lower magnitude constant load is applied over an extended period. There

Paper and board packaging accounts for 40% of the total packaging

are three distinct regions of creep deformation, primary, secondary,

market.1 Corrugated fibreboard boxes are a critical packaging element

and tertiary. Primary creep occurs when the load is applied and the

for local and international trade. Corrugated fibreboard boxes are cost

top and bottom flaps of the box are compressed and the load is trans-

effective and robust with good top-to-bottom compression strength.2

ferred to the perimeter of the box3 and the rate of box displacement

Boxes fail when an applied load exceeds their compressive strength;

is much greater than in secondary creep. During secondary creep, the

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2022 The Authors. Packaging Technology and Science published by John Wiley & Sons Ltd. Packag Technol Sci. 2022;35:497–504.

wileyonlinelibrary.com/journal/pts

497

GRAY-STUART ET AL.

F I G U R E 1 Box displacement over time for a box subjected to constant compression in cyclic humidity conditions. The vertical dashed lines separate the primary, secondary, and tertiary creep regions, respectively

box panels begin to bulge and the load is transferred to the corners of

would yield different conclusions regarding secondary creep rate and

the box.3–6 The cyclical nature of the displacement during secondary

box lifetime than creep tests performed on empty boxes.

creep in Figure 1 is a result of hygroexpansion as the paper is the

Cyclic RH creep tests can provide useful information about the

swelling and shrinking as the RH changes.5 In the tertiary region, box

performance of boxes for manufacturers.14,21,22 In practice, the RH

failure is initiated as a result of local buckling near the corners which

rarely

leads to hinge formation and ultimately catastrophic failure of the

conditions.23–25 As boxed products move through a supply chain, they

box.3,7,8

can experience periods of relatively constant RH interspersed with

exhibits

uniform

cycles

especially

refrigerated

It has been previously reported that the box compression

periods of variable RH. Thus, a secondary aim of this work was to

2,9–11

; likewise, failure rate due to

explore how cycle-interval tests consisting of periods of constant RH

creep is usually faster at higher relative humidities and previous

in between controlled RH cycles would influence the box lifetime and

research has reported higher secondary creep rates, shown to be

secondary creep rate. This approach could allow manufacturers to

closely related to shorter lifetimes6,12–16 under cycling RH conditions

simulate in a controlled testing facility the RH profiles experienced by

strength is affected by humidity

6,17,18

compared with constant RH.

However, findings by Hussain

et al.3 challenge this notion that box performance is worse when RH

their boxes in a supply chain and potentially economise this testing by focussing on the most harmful conditions experienced by the boxes.

is cycling as opposed to constant. They measured creep rates for a single type of box across a range of different cycling times under different constant vertical loads. They found that boxes subject to a 20%

MATERIALS AND METHODS

BCT or higher at constant 90% RH failed earlier than boxes at these loads exposed to cycling conditions between 50% and 90% RH. This

2.1

Materials

finding was attributed to creep time constants logarithmically shifting to shorter times as a result of the high applied load. Shorter creep

For this study, single walled C-flute regular slotted containers were

time constants mean larger creep rates. High loads and high moisture

used. The inner and outer liners were 200 and 250 gsm Kraft liner-

contents produced large enough creep rates to quickly dissipate stress

board made from New Zealand grown radiata pine with a 160 gsm

gradients leading to more creep than cyclic conditions.

semichem medium. The boxes were manufactured in New Zealand

Compressive creep tests are conventionally done on single empty

and obtained as flat packs with the manufacturer's flap preglued. They

boxes,3,18 and only recently, some researchers have put plastic balls

were stored in a controlled environment at 50% RH and 23 C. The

inside the box to prevent them from inward buckling.

In reality,

boxes are often palletised and contain product which may impart out-

outer dimensions of the assembled boxes were 385 248 295 mm (length width height).

of-plane loading on the box panels thus promoting bucking of panels.20 This can lower the top-to-bottom compression strength20 and may accelerate failure due to creep.21 Furthermore, during trans-

2.2

Box compression tests

port and storage, boxes are usually packed tightly on a pallet and only have one or two external side panels exposed to the ambient atmo-

Box compression tests (BCTs) were conducted to determine the

sphere. This is in contrast to having all four panels exposed in a tradi-

applied load for the creep tests. BCTs were conducted in accordance

tional creep test. The primary aim of this work was to see whether

to Australian and New Zealand standard (AS/NZS 1301.800s:2006). A

performing the compressive creep tests with boxes under conditions

Wiedemann universal tester was used for this testing. Boxes were

more aligned with those experienced in the refrigerated supply chain

compressed at a crosshead speed of 10 mm/min until failure. The

10991522, 2022, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/pts.2646 by Test, Wiley Online Library on [01/05/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

498

highest load prior to failure was recorded as the BCT load. Ten repli-

was used for this work. Four different compressive creep conditions

cate samples were used for the BCTs, and boxes were conditioned for

were performed for this study as detailed in Table 1. Boxes were sub-

48 h at 50% RH and 23 C prior to testing.

jected to 30% of the BCT for in all trials to represent highly loaded boxes, for example, those on the lowest layer of a pallet. The box conditioning protocol used by Hussain et al.3 was

2.3

Box preparation

employed for this study. Prior to preparing the boxes, they were conditioned for 48 h at 23 C and 50% RH as they would be for BCT.

Three preparations of boxes were used in this study: control, filled,

Once the boxes had been prepared, they were placed in a press in the

and foil boxes. Empty boxes were used as the control. The filled boxes

test room. All boxes were initially subjected to two 24-h humidity

contained 20 ± 0.2 kg of Chelsea® standard granulated white sugar.

cycles, consisting of 12 h at 70% RH and then 12 h at 90% RH with

Sugar was chosen as it has a similar bulk density (900 kg m 3) to the

no load applied. Each press was equipped with a load cell and linear

product normally contained in the boxes and is shelf stable. This left a

variable differential transformer (LVDT) which enabled the applied

headspace of ≈80 mm between the product and the top of the box

load and displacement to be measured, while the relative humidity

that ensured that the box would take the applied load and not the

and temperature in the test room was measured and recorded using

contents. Sugar is hygroscopic; to prevent unintended issues with

multiple sensors. All data were recorded at 5-min intervals. Table 1

moisture, the sugar was packed in two black plastic (LDPE) rubbish

outlines the RH conditions for the four trials. Trials (A) and (C) were

bags which were then sealed with foil tape. The foil boxes had two

stopped at the end of a 12-h 90% RH cycle, and trial (B) was stopped

adjoining external side panels, without the manufacturer's joint, cov-

at the end of a 5-day constant 90% period. This was to ensure the

ered in aluminium foil to represent a box on the corner of a pallet. The

moisture content of the boxes would be at their maximum for the

foil was secured with aluminium tape. All boxes were sealed with

respective trials. All trials were run for between 21 and 25 days.

standard brown packing tape holding the top and bottom flaps in place. The test facility had 24 presses available and for each trial eight replicates of three different box preparations were set up. Figure 2

2.5

Box lifetime and secondary creep rate

shows how the boxes looked with the foil coating applied to two adjacent panels.

The R code developed by Hussain et al.3 was used to determine secondary creep rate and box lifetime. Briefly, a method was developed to detect the peaks in the box displacement versus time data. For

2.4

Creep tests

boxes which did not fail, a linear regression was fitted through the peaks of the data between 20% and 80% of the experimental time

Cyclic RH creep tests often use a range of at least 40% RH, with cycling between 50% and 90% of RH being commonly used.6,15,26 In these trials, low and high RH levels of 70 and 90% at a temperature of 4.5 C were chosen. The rationale for this approach is that refrigerated

TABLE 1

Creep testing conditions

Trial

RH conditions

Cycling; 24 h cycles (12 h at 70% RH, 12 h at 90% RH)

Cycle/interval; 5 times 24 h cycles (12 h at 70% RH, 12 h at 90% RH), 5 days constant RH at 90%

Constant RH at 90%

Constant RH at 70%

storage and transport is particularly common for horticultural and agricultural exports. RH in refrigerated conditions is typically between 70% to 90% and the typical temperature range is 0–8 C and product dependent27,28; the boxes used in this study are made for refrigerated product. The WHITE (Weight Humidity Intervals Temperatures Experiments) room test facility at the Scion Te Papa Tipu Innovation Park

F I G U R E 2 Assembled box with two normal panels (A) and aluminium foil covering two adjacent panels (B), the top flaps of the box were sealed with tape after the aluminium foil was applied

499

GRAY-STUART ET AL.

period. Secondary creep rate is given by the absolute value of this gra-

packaging weight) on the boxes on the bottom layer of a pallet. It is

dient divided by the height of the boxes (295 mm). Figure 3 illustrates

important to acknowledge that the load distribution on a box in creep

peak detection method used to calculate the secondary creep rate.

and compression tests is simplified compared with a real-world sce-

For boxes which failed, a numerical differentiation method was used

nario. The stacking configuration, box misalignment, and the pallet

to see when the steepest gradient occurred and thus give the time at

itself all influence the load distribution.29–31

which a box failed. The secondary creep rate for boxes which failed used the same peak detection method; however, 10% to 90% of the time period was used in order to get a suitable secondary creep rate

3.2

Moisture content

value as the time period to failure was often much shorter than boxes which did not fail.

The moisture content of the board at the end of the creep tests is given in Table 2. Across the four different conditions used, the average moisture content was highest for the filled boxes followed by the

2.6

Moisture content

control, the nonfoil side from the foil covered box and the foil covered panels. Aluminium foil provides a complete barrier to moisture and

At the end of the trials, the moisture content of the boxes was mea-

restricts the direct vapour access to the covered panels, so the mois-

sured. The trials concluded with the 90% RH cycle apart from the con-

ture content will be lowest for the covered panels.

stant 70% RH trial. The four side panels from each box were cut out

It takes a long time for the board to reach equilibrium moisture

and weighed immediately after the test; they were then dried at

content as can be seen from the difference between the constant

105 C for 72 h to obtain the dry weight. The % moisture content of

90% RH condition and the two cycling trials where the boxes were

the board at the end of the trial was given by (wet weight-dry

only held at 90% RH for 12 h and 5 days, respectively. From the sorp-

weight)/wet weight.

tion and desorption isotherms for corrugated fibreboard presented in the literature,3,32,33 the equilibrium moisture content for sorption at 90% RH and desorption at 70% RH are similar. We hypothesise that

RESULTS AND DISCUSSION

even during the cycling RH in trial A the mean moisture content of the panels has a narrower range than the equilibrium moisture con-

3.1

Box compression tests

tent at 70% and 90% RH, respectively. In all trials, the highest moisture content was measured for the

The mean BCT value measured was 4.41 kN (450 kg force) with a

filled boxes (Table 2). This indicates that the actual moisture content

standard deviation of 0.186 kN (18.9 kg force); 30% of the BCT value

of boxes in the supply chain could be higher than what is measured

was chosen for the creep tests as it gives a load of 1.32 kN (135 kg

from empty boxes in compressive creep tests. However, this differ-

force), which is close to the gross maximum load that these boxes

ence may not be significant enough to influence box behaviour. Hav-

would experience when palletised in the supply chain. The boxes used

ing product inside the box might result in the inner liner having a

in this study are typically palletised with an interlock pattern six high,

higher moisture content. In an empty box, moisture from the inner

which is an equivalent total load of 1.23 kN (125 kg force plus

liner desorbs into the air space and is adsorbed by the top and bottom

F I G U R E 3 Example of box displacement data over time for a box from trial A. The black dots indicate peaks and the solid grey lines are linear regressions through the peaks and a rolling mean respectively, taken within the second and eighth data quantiles represented by the outermost dotted vertical lines Trial

Control

Filled boxes

Foil sided bare

Foil sided covered

13.4 (0.25)b

14.0 (0.34)a

13.3 (0.32)b

12.2 (0.27)c

14.2 (0.28)a,b

14.5 (0.22)a

14.1 (0.36)b

13.1 (0.31)c

14.7 (0.55)a

14.9 (0.25)

11.0 (0.21)a,b

15.0 (0.40)

14.7 (0.59)

11.1 (0.13)a

11.0 (0.20)a,b

10.8 (0.14)b

Note: For each trial, means followed by a common letter are not significantly different by the HSD test at 5% level of significance.

T A B L E 2 Moisture content (% wet basis) of the board at the completion of the trials, mean with standard deviation in brackets

500

flaps. If there is a product occupying most of the internal space, the

faster rate. The overall strength and response to loading of these

rate of mass transfer from the inner liner to the air space and box flaps

panels could be altered by this imbalance in moisture content

will be reduced. This will result in the inner liner of the panels having

between the inner and outer liners and result in the panels bowing

a higher moisture content as there is less moisture transfer to the air

inwards.

space and box flaps than in an empty box. As can be seen Table 2, some preparations affect the moisture

This inward deflection would not occur under supply chain conditions as the product in the box would provide support and prevent

content under some test conditions. The moisture content and its var-

this from happening. This is shown in Figure 4C,D which shows the

iation in fibreboard during cycling for different box preparations is

uncovered and foil covered panels of the same box which failed in

something which has not previously been investigated. The response

trial (B).

of moisture content in relation to changes in RH is further compli-

The mean box lifetime for the filled boxes was around half that of

cated by the adsorption and desorption phenomena which is also

the control boxes in trials (B) and (C). The boxes with foil coated

worth pursuing in future studies. Given the correlation between box

panels had the longest lifetime and lowest creep rate across all trials.

performance and moisture content such information could help

The mean and median box lifetimes were similar with the largest dif-

understand vulnerability of boxes to creep.

ference being 2.4 days for the control boxes in trial B. If the number of box failures is low the box lifetime in is not a useful metric. However, the box failure rate provides a good indica-

3.3

Box failure and lifetime

tion of relative box performance across different preparations and test conditions. The failure rate of boxes which experienced 12-h cycling

Boxes were examined at the end of the trials to assess the failure

was lower than those at constant 90% RH (Table 3), this finding is in

they experienced. Failure was observed in all trials and preparations

line with Hussain et al.3 but in contrast to several previous studies It is

except for constant RH 70% and the foil covered boxes with the

noteworthy that no foil boxes under cycling conditions failed while a

12-h cycling time where there were no failures; 100% failure was

significant number of foil boxes failed when exposed to constant 90%

observed for the control and filled boxes in trial B. The type of fail-

RH and the cycle/interval conditions. These results support the notion

ure exhibited by the control and filled boxes was as previously

that exposure to constant high RH% can be worse for box perfor-

26,34

where buckling occurs in the corners which results in

mance than cycling conditions with a load greater than 20% BCT.

hinge formation leading to out-of-plane displacement on the larger

Furthermore, this shows that if one wants to mimic the conditions a

side panels (Figure 4A,B). An interesting observation was that boxes

box will experience in the supply chain, periods of constant high RH

with the foil coating behaved differently to the control and filled

should not be omitted and may and increase creep rate more so than

boxes where the panels with foil buckled inwards. Having foil on

continuous cycling. Further research in this area will undoubtedly be

the outer liner likely results in the inner liner gaining moisture at a

of some benefit to the packaging industry.

described

F I G U R E 4 Manifestations of box failure as a result of creep deformation observed in this study: (A) and (B) show all panels of a control box in which it can be seen that creases and hinges form at the corners of the box which leads to buckling and global failure; (C) and (D) show the panels of a foil box, where similar creases and hinge formation is observed while the foil coated panels moved inward, this was observed for all foil boxes which failed

501

GRAY-STUART ET AL.

TABLE 3

Box lifetime results for each trial in this study

Trial

Preparation

Median life time (days)

Mean life time (days)

CV (%)

Number of boxes

Number of failures

Failure rate

Control

11.4

14%

Filled

12.7

12.3

75%

Foil

n/a

Control

12.4

100%

Filled

5.5

5.6

100%

Foil

16.0

15.9

83%

Control

7.2

9.6

50%

Filled

3.4

5.4

101

88%

Foil

11.1

10.4

71%

Control

n/a

Filled

n/a

Foil

n/a

TABLE 4 30% BCT

Mean secondary creep rate for all trials with boxes at

rate of the filled boxes is significantly different from the control and foil boxes, while there is no difference between the control and foil

Trial

Condition

Creep rate per day

CV (%)

Log creep rate

box preparations. These results show that the internal pressure from

Control

2.82E 04a

74%

8.17

the box fill can have a significant negative impact on box performance

Filled

8.90E 04

36%

7.02

Foil

1.31E 04a

24%

8.94

Control

8.12E 04a

24%

7.12

Filled

1.57E 03b

20%

6.45

Foil

5.23E 04a

52%

7.56

decreasing with increasing moisture content. A likely mechanism is

Control

9.36E 04a

88%

6.97

that at higher moisture contents the stiffness of the panels decrease

Filled

2.88E 03b

56%

5.85

to a point where the internal pressure from the box fill can increase

Foil

7.05E 04a

61%

7.26

the rate of panel bulging relative to the control and in turn increase

Control

1.78E 05b

25%

10.9

the creep rate. These results give merit to having different box prepa-

2.92E 05

32%

10.4

rations in creep tests as box performance is significantly affected

2.28E 05

a,b

22%

10.7

when presented in a way that is more representative of supply chain

Filled Foil

Note: For each trial, the secondary creep rate for each box preparation was compared with a post hoc Tukey HSD test. Means that do not share a letter are significantly different.

and creep rate under certain conditions. At constant 70% RH, the box fill had less of an influence on creep rate, there was a significant difference between the filled and control boxes but not the filled and foil boxes. The reason why the filled boxes performed worse at higher humidities could be due to the mechanical properties of paper

conditions. There is no significant difference in the creep rates of the foil and control boxes within the same trial. In constant RH conditions, the foil does not prevent the box panels from reaching the same moisture

3.4

Secondary creep rate

content as the uncoated panels so the creep rate will be similar. However, under cycling conditions, the foil has a significant effect on the

The mean creep rate for each trial is shown in Table 4, and the creep

moisture content of those panels as the 12 h cycle time is not long

rate data are presented in a box and whisker plot in Figure 5. A post

enough for them to reach equilibrium. While the difference in creep

hoc Tukey HSD test was performed to determine if there were signifi-

rate is not statistically significant, Figure 5 shows that the maximum

cant differences in the mean creep rate of the box preparations within

creep rate observed for the foil boxes is lower than the median for

each trial and to compare the effect the RH conditions had on each

the control. Extrapolation box performance from creep tests on nor-

box preparation (Table 5). The coefficient of variation (CV) for creep

mal boxes could result in creep rate and box lifetime being under-

rate is higher than found in most previous studies3,26,32; however, it is

predicted as box performance is influenced by uneven distribution of

worth noting that CV was positively correlated with %BCT in the

moisture content. When boxes are palletised, boxes on the side of the

study by Hussain et al.3 and the load used in this study is at the upper

pallet have only one panel exposed to the ambient conditions and

end of this range. The control in trials A and C have a notably higher

boxes within the pallet can have all surfaces in contact with other

CV of 74% and 88% and the failure rate of boxes in these tests was

boxes and no ambient exposure.

14 and 50%, respectively. This tends to skew the variation in creep

The findings here demonstrate that the creep rate and box life-

rate as the boxes which fail, especially if they fail early on, usually

time are highly dependent on how the box is prepared. Notably the

have a considerably higher creep rate. For trials A, B, and C, the creep

boxes with product performed considerably worse, having a shorter

502

F I G U R E 5 Secondary creep rate from all trials, box length depicts the interquartile range and the median is the horizontal line in the box, whiskers represent the maximum and minimum ranges of the data, except the outliers (black circles) which exceed 1.5 times the interquartile range T A B L E 5 Comparison of secondary creep rate for box preparation as function of trial conditions Box preparation Control

Filled boxes

Foil boxes

chain conditions where boxes contain product and do not have uniform exposure to the ambient conditions. It is acknowledged that dynamic loading and vibration are two other phenomena which fur-

Trial condition

Secondary creep rate (day 1) 9.36E 04

Alternate

8.12E 04

Cycling

2.29E 04b

Constant 90% RH

ther impair box performance and are important in real world scenarios,24 the stiffness of pallet deckboards also influence box compression strength.31 However, these aspects have not been considered here due to cost and complexity and because the primary aim of this work was to isolate humidity effects on box performance.

Constant 70% RH

1.80E 05

Constant 90% RH

3.69E 03a

Alternate

1.57E 03b

The secondary creep rate and lifetime of boxes containing product

Cycling

9.72E 04

was significantly shorter than the control and foil-covered boxes. This

Constant 70% RH

3.10E 05d

was attributed to the internal pressure imparted on the panels by the

Constant 90% RH

8.00E 04a

Alternate

5.23E 04a

with foil had lower moisture uptake and performed better than the

Cycling

1.31E 04b

control in cycling conditions. The resultant lower moisture content of

Constant 70% RH

2.30E 05b

the coated and uncoated panels of this box preparation means the

CONCLU SIONS

product; this can result in out-of-plane displacement of the side panels manifesting much earlier leading to a higher creep rate and shorter lifetime. Conversely, boxes which had two panels covered

Note: Outliers identified using the interquartile range (IQR) criterion have been removed. Means that do not share a letter are significantly different.

box remains stronger for longer. Furthermore, the foil acts as a barrier so the panels are not subjected to as larger changes in moisture content so the MC% will remain closer to the mean value. These results show that future studies should consider mimicking

lifetime and higher creep rate than the other two preparations. Fac-

the actual surface available for moisture transport as it has a significant

tors such as the internal pressure from the product20 and the distribu-

influence on the box lifetime. The lifetime of the filled boxes in the

tion of moisture content of the box panels can significantly affect box

cycle-RH interval tests was shorter than those which experienced only

performance. Including these enables the box performance to be

cycling conditions, but those exposed to constant 90% RH had the

quantified in conditions which are more representative of supply

shortest lifetime. The results presented here further support the findings

503

GRAY-STUART ET AL.

of Hussain et al.8 that conditions of constant high humidity can result in poorer box performance than cycling when the load is greater than 20% BCT and therefore that this factor plays an important role in box failure. ACKNOWLEDGEMEN T Open access publishing facilitated by Massey University, as part of the Wiley - Massey University agreement via the Council of Australian University Librarians. DATA AVAI LAB ILITY STATEMENT The data that support the findings of this study are available from the corresponding author upon reasonable request. Open access publishing facilitated by Massey University, as part of the Wiley - Massey University agreement via the Council of Australian University Librarians. ORCID Eli M. Gray-Stuart

https://orcid.org/0000-0002-0820-3131

John E. Bronlund

https://orcid.org/0000-0002-7556-7752

REFER ENC ES 1. Market Statistics and Future Trends in Global Packaging. 2008, World Packaging Organisation. WWW.worldpackaging.org 2. Frank B. Corrugated box compression—a literature survey. Packaging Technology and Science. 2014;27(2):105-128. doi:10.1002/pts.2019. 3. Hussain S, Coffin DW, Todoroki C. Investigating creep in corrugated packaging. Packaging Technology and Science. 2017;30(12):757-770. doi:10.1002/pts.2323. 4. Köstner V, Ressel JB, Sadlowsky B, Böröcz P. Measuring the creep behaviour of corrugated board by cascade and individual test rig. Journal of Applied Packaging Research. 2018;10(1):4. doi: 10.14513/actatechjaur.v10.n2.445. 5. Urbanik TJ. Hygroexpansion-creep model for corrugated fiberboard. Wood and Fiber Science. 1995;27(2):134-140. 6. Urbanik TJ, Lee SK. Swept sine humidity schedule for testing cycle period effects on creep. Wood and Fiber Science. 2007;27(1):68-78. 7. Coffin DW, Niskanen K, Gustafsson P, Berglund L, Hagglund R, Mechanics of Paper Products. 2011, De Gruyter, doi:10.1515/ 9783110254631 8. Zhao LL. Evaluation of the Performance of Corrugated Shipping Containers: Virgin Versus Recycled Boards. Victoria University of Technology; 1993. 9. Allaoui S, Aboura Z, Benzeggagh M. Effects of the environmental conditions on the mechanical behaviour of the corrugated cardboard. Composites Science and Technology. 2009;69(1):104-110. doi:10.1016/j.compscitech.2007.10.058. 10. Marcondes J. Corrugated fibreboard in modified atmospheres: moisture sorption/desorption and shock cushioning. Packaging Technology and Science. 1996;9(2):87-98. doi:10.1002/pts.2770090204. 11. Navaranjan N, Dickson A, Paltakari J, Ilmonen K. Humidity effect on compressive deformation and failure of recycled and virgin layered corrugated paperboard structures. Compos Part B Eng. 2013;45(1): 965-971. doi:10.1016/j.compositesb.2012.05.037. 12. Bronkhorst C. Towards a more mechanistic understanding of corrugated container creep deformation behaviour. Journal of Pulp and Paper Science. 1997;23(4):J174-J181. 13. Koning Jr J, Stern R. Long-term creep in corrugated fiberboard containers. Tappi [Technical Association of the Pulp and Paper Industry], 1977. 14. Leake C. Measuring corrugated box performance. Tappi Journal. 1988;71(10):71-75.

15. Leake C, Wojcik R. Humidity cycling rates: how they influence container life spans: Corrugated containers. Tappi Journal. 1993;76(10):26-30. 16. Urbanik T. A more mechanistic model of the compression strain-load response of paper. Journal of Pulp and Paper Science. 2002;28(6): 211-216. 17. Habeger Jr CC, Coffin D. The role of stress concentrations in acceleration creep and sorption-induced physical aging. 1999. 18. Van Hung D, Nakano Y, Tanaka F, Hamanaka D, Uchino T. Preserving the strength of corrugated cardboard under high humidity condition using nano-sized mists. Composites Science and Technology. 2010; 70(14):2123-2127. doi:10.1016/j.compscitech.2010.08.011. 19. Sherman NNL. Investigation into the effect product can have on box failure during creep tests. 2012. 20. Peleman D, Singh J, Saha K, Roy S. Evaluation of a bulge reduction technology for corrugated fiberboard containers under static compression. Journal of Applied Packaging Research. 2020;12(1):6. 21. Coffin DW. The creep response of paper. in 13th Fundamental Research Symposium, Cambridge. 2005. 22. Morgan DG. A mechanistic creep model and test procedure. Appita: Technology, Innovation, Manufacturing, Environment. 2004;57(4):299 doi:10.1016/B978-012226570-9/50076-4. 23. Nevins AL. Significant Factors Affecting Horticultural Corrugated Fibreboard Strength: A Thesis Presented in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy in Food Engineering at Massey University, Palmerston North, New Zealand. Massey University; 2008. 24. Eagleton DG. Creep Properties of Corrugated Fibreboard Containers for Produce in Simulated Road Transport Environment. Victoria University of Technology; 1995. 25. Ruiz-Garcia L, Barreiro P, Robla JI, Lunadei L. Testing ZigBee motes for monitoring refrigerated vegetable transportation under real conditions. Sensors. 2010;10(5):4968-4982. doi:10.3390/s100504968. 26. Kutt H, Mithel B. Studies on compressive strength of corrugated containers. Tappi. 1968;51(4):A79. 27. Gray-Stuart E. Unpublished data—Pallet transfer trial of dairy products in refrigerated shipping container. 2018. 28. Lukasse L and Leentfaar G, Humidity control and fresh air exchange in reefer containers: lowest feasible relative humidity, temperature and energy consumption. 2020. 29. Singh SP. Instability of stacked pallet loads due to misalignment. Journal of Testing and Evaluation. 1999;27(5):349-354. doi:10.1520/JTE12236J. 30. Baker MW. Effect of pallet deckboard stiffness and unit load factors on corrugated box compression strength. Virginia Tech. 2016;29(4-5): 263-274. doi:10.1002/pts.2201. 31. Quesenberry C, Horvath L, Bouldin J, White MS. The effect of pallet top deck stiffness on the compression strength of asymmetrically supported corrugated boxes. Packaging Technology and Science. 2020; 33(12):547-558. doi:10.1002/pts.2533. 32. Byrd V, Koning Jr J. Corrugated fiberboards: edgewise compression creep in cyclic relative humidity environments [Southern pine pulps]. Tappi [Technical Association of the Pulp and Paper Industry], 1978. 33. Popil RE, Hojjatie B. Effects of component properties and orientation on corrugated container endurance. Packaging Technology and Science. 2010;23(4):189-202. doi:10.1002/pts.889. 34. Niskanen K. Mechanics of Paper Products. Walter de Gruyter; 2011.

How to cite this article: Gray-Stuart EM, Wade K, Redding GP, Parker K, Bronlund JE. Influence of different box preparations on creep performance of corrugated fibreboard boxes subject to constant and cycling relative humidity environments. Packag Technol Sci. 2022;35(6):497-504. doi:10.1002/pts.2646

504

PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

Angle of the Perforation Line to Optimize Partitioning Efficiency on Toilet Papers JOANA COSTA VIEIRA 1, ANDRÉ COSTA VIEIRA 2, MARCELO L. RIBEIRO 3, PAULO T. FIADEIRO 1 & ANA PAULA COSTA 1 Currently, tissue product producers try to meet consumers’ requirements to retain their loyalty. In perforated products, such as toilet paper, these requirements involve the paper being portioned along the perforation line and not outside of it. Thus, it becomes necessary to enhance the behavior of the perforation line in perforated tissue papers. The current study aimed to verify if the perforation line for 0° (the solution found in commercial perforated products) is the best solution to maximize the perforation efficiency. A finite element (FE) simulation was used to validate the experimental data, where the deviations from the experiments were 5.2% for the case with a 4 mm perforation length and 8.8% for a perforation of 2 mm, and optimize the perforation efficiency using the genetic algorithm while considering two different cases. In the first case, the blank distance and the perforation line angle were varied, with the best configuration being achieved with a blank distance of 0.1 mm and an inclination angle of 0.56°. For the second case, the blank distance was fixed to 1.0 mm and the only variable to be optimized was the inclination angle of the perforation line. It was found that the best angle inclination was 0.67°. In both cases, it was verified that a slight inclination in the perforation line will favor partitioning and therefore the perforation efficiency. Contact information: 1 Fiber Materials and Environmental Technologies (FibEnTech-UBI), Universidade da Beira Interior, R. Marquês D’Ávila e Bolama, 6201-001 Covilhã, Portugal 2 Center for Mechanical and Aerospace Science and Technologies (C-MAST-UBI), Universidade da Beira Interior, R. Marquês D’Ávila e Bolama, 6201-001 Covilhã, Portugal 3 Department of Aeronautical Engineering, University of São Paulo, Av. João Dagnone, 1100-Jardim Santa Angelina, São Carlos 13563-120, SP, Brazil Eng 2023, 4, 80–91. https://doi.org/10.3390/eng4010005 Creative Commons Attribution 4.0 License

Page 1 of 13

Article 2 – Tissue Perforation Optimisation

Article

Angle of the Perforation Line to Optimize Partitioning Efﬁciency on Toilet Papers Joana Costa Vieira 1, * , André Costa Vieira 2 , Marcelo L. Ribeiro 3 , Paulo T. Fiadeiro 1 1

and Ana Paula Costa 1

Fiber Materials and Environmental Technologies (FibEnTech-UBI), Universidade da Beira Interior, R. Marquês D’Ávila e Bolama, 6201-001 Covilhã, Portugal Center for Mechanical and Aerospace Science and Technologies (C-MAST-UBI), Universidade da Beira Interior, R. Marquês D’Ávila e Bolama, 6201-001 Covilhã, Portugal Department of Aeronautical Engineering, University of São Paulo, Av. João Dagnone, 1100-Jardim Santa Angelina, São Carlos 13563-120, SP, Brazil Correspondence: joana.costa.vieira@ubi.pt

Abstract: Currently, tissue product producers try to meet consumers’ requirements to retain their loyalty. In perforated products, such as toilet paper, these requirements involve the paper being portioned along the perforation line and not outside of it. Thus, it becomes necessary to enhance the behavior of the perforation line in perforated tissue papers. The current study aimed to verify if the perforation line for 0◦ (the solution found in commercial perforated products) is the best solution to maximize the perforation efficiency. A finite element (FE) simulation was used to validate the experimental data, where the deviations from the experiments were 5.2% for the case with a 4 mm perforation length and 8.8% for a perforation of 2 mm, and optimize the perforation efficiency using the genetic algorithm while considering two different cases. In the first case, the blank distance and the perforation line angle were varied, with the best configuration being achieved with a blank distance of 0.1 mm and an inclination angle of 0.56◦ . For the second case, the blank distance was fixed to 1.0 mm and the only variable to be optimized was the inclination angle of the perforation line. It was found that the best angle inclination was 0.67◦ . In both cases, it was verified that a slight inclination in the perforation line will favor partitioning and therefore the perforation efficiency. Citation: Vieira, J.C.; Vieira, A.C.;

Keywords: FE model; optimization; perforation efﬁciency; perforation line angle; tissue toilet paper

Ribeiro, M.L.; Fiadeiro, P.T.; Costa, A.P. Angle of the Perforation Line to Optimize Partitioning Efﬁciency on Toilet Papers. Eng 2023, 4, 80–91.

1. Introduction

https://doi.org/10.3390/

At the present time, there is a need for products that result in the use of less disposable material by environmentally conscious consumers. In the tissue paper converting industrial process, this has encouraged manufacturers to produce products with the ability to be partitioned [1]. In the production of ﬁnished tissue paper products, such as facial papers, paper towels and toilet papers, transversal perforation lines are used to facilitate the separation of the roll into individual “sheets” or services needed by the consumer. This feature of perforation allows the consumer to conveniently dispense a certain amount of the product according to their convenience [2]. Perforation takes place in the tissue paper converting machine when the sheet of paper passes through a nip between a stationary anvil and the perforator blades. These blades are usually mounted on a rotating cylinder and have alternately spaced teeth and notches. Both the anvil and the perforator are skewed in the machine direction (MD) to decrease the impact of the blade against the anvil by reducing vibration and keeping the cut line perpendicular to the MD of the tissue paper sheet. It is important that the perforator blades produce the desired cut in the ﬁnished product, so that consumer acceptance is as intended. The quality of the product cannot be affected by this operation due to poor distribution or the type of perforations. On the other hand, there has to be a balance between the number of cuts, the dimension of the cuts, the number of

eng4010005 Academic Editor: Antonio Gil Bravo Received: 23 November 2022 Revised: 19 December 2022 Accepted: 20 December 2022 Published: 1 January 2023

Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

Eng 2023, 4, 80–91. https://doi.org/10.3390/eng4010005

https://www.mdpi.com/journal/eng

Eng 2023, 4

spacings, the dimension of the spacings and the number of plies, so that the partition of the paper roll partition by the consumer is neither easy nor too hard [3–5]. This balance is called the perforation efficiency and can be determined accordingly to the standard [6] by Equation (1): Sp (1) E p = 100 1 − Snp where E p is the perforation efficiency (%), S p is the average tensile strength of perforated papers (N/m) and Snp is the average tensile strength of unperforated papers (N/m). During the tissue paper manufacturing process, raised up cellulosic fibers are found on the sheet surface, which help in consumer hygiene, but which in excess can form agglomerates, impairing the quality of the final product. To reduce the loss of cellulosic fibers on the paper surface, it is desirable that the perforation blade have relatively thin teeth [3,4]. Thus, the proper geometry of the blade must be considered. The perforator is also responsible for the visual appearance of the free edge of the remaining paper roll. The consumer wants an aesthetically pleasing free edge (smoother and less irregular between the cut and uncut areas) after tearing off the desired amount of paper [3,4]. The geometric discontinuity of the perforation line will affect the existing stress field in this area, thus affecting the stress concentration factor and consequently the final efficiency. The ratio between the highest value in a geometric discontinuity and the nominal stress in the minimum cross section is called the stress concentration factor [7]. In a previous work develop by Vieira et al. [8], they concluded that in toilet paper samples with a stress concentration factor above 0.11, a tear occurs at other locations away from the perforation line. On the other hand, toilet papers with a stress concentration factor below 0.11 tear along the perforation line. Another study carried out by Vieira et al. [9] showed that the perforation efficiency increases with an increase in the cut distance, stabilizing with a cut distance of 6 mm. The predicted differences of numerical simulations, when compared to experimental tests, decreases from 27% to 4% with a cutting distance ranging from 2 mm to 8 mm. However, the numerical simulations shown a trend in terms of the stabilization of the perforation efficiency for a cutting distance of 6 mm. The current study aimed to verify if the perforation line at 0◦ is the best solution to maximize the perforation efficiency. To carry out this study, four commercial two-ply toilet papers were tested with the line of perforation at several angles. The perforation efficiency was evaluated at each angle. According to the authors’ knowledge, there are limited studies on this subject. 2. Simulation–Materials and Methods 2.1. Optimization The optimization of a constrained problem, using discrete variables, is better performed using the genetic algorithm (GA) [10] than using gradient-based methods, with the use of the GA avoiding the trap of local minima [11]. For this problem, the objective was to find the minimum force necessary to detach the toilet paper service by optimizing the angle α and the blank distance d of the paper cuts (see Figure 1), where the cut distance was maintained constant in all simulations (c = 3 mm). Additionally, a second optimization was performed regarding only the angle α by maintaining the blank distance d = 1.0 mm. As usual, the design variables were coded as genes (coded as integer numbers) grouped into chromosomes (strings). The chromosomes were weighted as the fitness function (minimum force), representing the chromosome phenotype. Populations of possible optimal values were generated considering their probabilistic characteristics, which evolved over generations through reproductions. To avoid local minima, it is necessary to use enough search points within the design variables space [10]. The GA algorithm begins with a random population and assesses the fitness function. Reproduction is carried out by selecting the best individuals and generating the offspring. During reproduction, the genes can be exchanged by the crossovers [11].

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Figure 1. Design parameters.

The optimization parameters regard a population of 40 individuals (20 times the design parameters) and 150 generations (or as many generations as it takes for a convergence criterion to be reached), with 20% of mutation parameters and 50% crossover probability [12]. As mentioned before, the objective was to minimize the force to detach the toilet paper regarding specific design constrains, i.e., the angle, α, which ranged from 0◦ to 55◦ , and the blank distance, d, between the cuts, which ranged from 0.1 to 1.0 mm. The GA created an angle, α, and a blank distance, d, population at random based on the angle range of interest. These parameters needed to be qualified according to how they may be more able than others to achieve the design objective. When this was carried out by using the finite element (FE) model, population crossing could produce a new generation, which was again qualified by the FE model, and this process was repeated until the best generation was found, as shown by the flowchart in Figure 2. After each crossing, the algorithm made an elitism pre-definition, comparing the new generation with the previous one, and selecting the best members to compose the next generation to be crossed. For the genetic algorithm, the mutation probability is 1% and the crossover probability is 100%. Regarding the optimization flowchart presented in Figure 2, four routines were developed separately: i. ii. iii. iv.

a Python script to modify the FE model regarding the GA design parameters; a Python script to perform the FE results analyses (post-processing); a Fortran subroutine for the material model (more details in the section below); a MATLAB® script to control the FE analysis and GA.

The optimization process was controlled using the MATLAB® GA algorithm. The analysis started when MATLAB® GA generated the ﬁrst generation of design parameters. Then, a Python script was called to modify the FE model regarding the design parameters. After that, the MATLAB® ran the FE analysis with the material model. Die to the fact that explicit FE analyses can take a long time and the GA algorithm demands a considerable number of analyses, it was necessary to obtain the maximum force value and terminate the current analysis. This was performed by the MATLAB® code and a Python script that accesses the ABAQUSTM results several times until it detected a reduction of 20% in terms of the maximum force.

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Figure 2. Analysis ﬂowchart.

2.2. Material Model It is not possible to adopt the isotropic behavior for tissue paper if the kind of paper has different behaviors in the machine and cross directions [8], and ABAQUSTM does not have a native constitutive law to model plasticity for orthotropic materials. Hence, a user material subroutine for explicit simulations (VUMAT) was implemented to simulate the orthotropic elastic–plastic behavior for the paper sheet. The material model, proposed by Mäkelä and Östlund [13], allows the paper anisotropic behavior to be accounted for, since the paper response is highly dependent on the ﬁber orientation. The model assumes the decomposition of the strain tensor into an elastic strain tensor and a plastic strain tensor (Equation (2)) while conserving the volume. p

ε ij = εeij + ε ij

(2) p

where ε ij is the total strain, εeij is the elastic strain, and ε ij is the plastic strain. The material model adopts the concept of an isotropic plasticity equivalent material [14], a ﬁctitious material that relates the orthotropic stress state to the isotropic stress state. Equation (3) gives the relation between the Cauchy stress tensor and the isotropic plasticity equivalent (IPE) deviatoric tensor. sij = Lijkl σkl

(3)

where sij is the deviatoric IPE stress tensor, σkl is the Cauchy stress and Lijkl is the fourth order transformation tensor shown in Equation (4) for plane stress. ⎡

2A ⎢C − A − B L=⎢ ⎣B − C − A 0

C−A−B 2B A−B−C 0

⎤ 0 0 ⎥ ⎥ 0 ⎦ 3D

(4)

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where the parameters A, B, C and D are calibrated from the experimental results at 0◦ (MD—machine direction) and 90◦ (CD—cross direction) without perforation obtained in a previous work [15], using the following Equations (5)–(12) [11]: A=

1 − 12x2

(5)

B = 3( y − x )

(6)

C = 3( y + x )

(7)

n ( n +1)

D= x=

K12 √

(8)

α2 β+1− 24(3α2 + β2 − 4β + 4) y=

6β − 3α2 − 3

α −A 4x

2n ( n +1)

α = K33

2n ( n +1)

β = K33

(9) (10)

( n +1) − K22

(11)

2n ( n +1)

+ K22

(12)

The parameters Kii and n are related to the curve ﬁt of the tensile test applying the Ramberg–Osgood methodology. For the MD tensile test (see Equation (13)): ε 11 =

σ11 + E11

σ11 E0

n (13)

For the CD (see Equation (14)): σ ε kk = kk + Ekk

Kkk Ekk E0

, k = 2, 3

(14)

Note that for Equation (13), the repeated indices do not mean the usual summation rule used in the indicial notation. Finally, the parameter K12 is obtained using Equation (15). γ12 =

σ12 + G12

K12 σ12 E0

n (15)

The Hooke’s law for plane stress, small strain, linear elastic orthotropic material is given using Equation (16). (16) σ = C : εe Where σ is the second order Cauchy stress tensor, C is the four-order plane stress, linear elastic, orthotropic constitutive law tensor and εe is the second order small strain elastic tensor using matrix notation. 2.3. Finite Element Model The implementation of this model follows the well-known J2 ﬂow theory for isotropic materials using the backward Euler algorithm [11]. The explicit solver was used to overcome convergence issues that are common when using the implicit solver for this type of simulation. On the other hand, the stable time increment is very small, which increases the computational costs. Simulations were performed using a workstation with two intel Xeon E5-2630 8 cores (16 cores total with 32 threads) with 256 Gb ram. The FE model dimensions, and boundary conditions are presented in Figure 3. The boundary conditions were imposed to represent a tensile test. Thus, all the displacement degrees of freedom are restricted (see Figure 3) in one side, and a prescribed displacement

Eng 2023, 4

was applied on the reference point. A rigid link between the reference point and paper edge was used to connect the paper and the reference point.

Figure 3. Finite element model and boundary conditions.

Modeling the tensile test using the reference point to apply the prescribed displacement was important for the post-processing once the number of procedures for the automatic results analysis had been reduced. This strategy does not affect the analysis results, as the resultant applied forces are the same for the case where a prescribed displacement is applied in each boundary node [8]. The paper was simulated using a four-node reduced integration membrane element (M3D4R). The model has a total of 11,086 elements and due to the cuts, a free mesh was used. It is important to mention that the mesh parameters did not change for all simulations. The material properties for the material model are: E11 = 13.89 MPa, E22 = E33 = 4.23 MPa, μ = 0.33 and G12 = 2.1 MPa. The parameters for the IPE model consider K22 = K33 since the mechanical behavior in the CD (direction 2) is similar to that in the thickness direction (direction 3). Thus, A = 1, B = 2.40, C = 2.40 and D = 1.38. 3. Experimental Tests–Materials and Methods 3.1. Materials Four commercial two-ply toilet papers were selected. These toilet papers were identified A to D. It was previously verified that two of the two-ply papers tear off the perforation when loaded manually (toilet papers A and B). The other two papers tear on the perforation when loaded manually. 3.2. Methods The grammage was determined accordingly with the standard ISO 12625-6:2005 [16] and defined as the mass per unit paper area (g/m2 ). A Mettler Toledo PB303 Delta range analytical balance (Mettler Toledo, Columbus, OH, USA) was used to determine the paper sample weight. To determine the thickness, where a stack of sheets of paper or a sheet of paper were/was compressed at a given pressure between two parallel plates, a FRANKPTI® Micrometer (FRANK-PTI GMBH, Birkenau, Germany) was used, in accordance to the standard ISO 12625-3:2014 [17]. According to this standard [17], the bulk, which is the inverse of density, can be determined by using the grammage and thickness previously determined. According to the standard ISO 12625-12:2010 [5], the perforation line was evaluated. On a Thwing-Albert® VantageNX Universal Testing Machine, tensile tests were performed in the MD for all samples. For each paper, samples were prepared with the perforation in the center (0◦ ) and with the line of perforation at different angles (20◦ , 30◦ , 37.5◦ , 41◦ and 45◦ ). Other samples were also prepared, of each paper, with the length of a single “sheet”

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without perforation but with the orientation of the corresponding angle to annulate the ﬁber orientation contribution (see Figure 4)

Figure 4. Experimental set-up to test non-perforated and perforated toilet papers. (F shows the force direction applied in the tensile test).

The cut and blank distances measurements were made with a paquimeter and repeated in 10 different perforations for each toilet paper sample. 4. Results and Discussion Structural characterizations were carried out on the four commercial two-ply toilet papers samples, according to the above-referred standards. Table 1 shows the results in terms of grammage, thickness, bulk, cut and blank distances for all toilet paper samples. Table 1. Physical characterization of the toilet papers: number of plies, grammage, thickness, bulk, cut and blank distance. Ш

Toilet Paper ID

N◦ Plies

A B C D

2 2 2 2

Ш Grammage (g/m2 )

Ш Thickness (μm)

Ш Bulk (cm3 /g)

Ш Cut Distance (mm)

Blank Distance (mm)

36.6 35.4 32.4 44.9

±0.64 ±0.26 ±0.42 ±0.71

374 305 611 345

±10.4 ±12.4 ±4.4 ±8.7

10.2 8.6 19.1 7.7

±0.36 ±0.37 ±0.41 ±0.27

1.5 1.9 4.0 2.3

±0.05 ±0.05 ±0.05 ±0.05

1.0 1.2 1.0 1.0

±0.05 ±0.10 ±0.05 ±0.05

Looking at Table 1, the grammage shows values in the range of 32.4–44.9 g/m2 . Evaluating the outcomes for the thickness and bulk, values vary between 51% and 60%, respectively, due to the embossing process type. Figure 5 shows the perforation efficiency behavior as function of the perforation line angle obtained for all toilet paper samples. Analyzing Figure 5, a decreasing trend in perforation efficiency can be observed with an increasing perforation line angle. Although the selected toilet papers present different characteristics, it was demonstrated that they present the same tendency in this regard. This fact is in line with what it was found by Vieira et al. [9], who stated that the perforation efficiency depends on the cut dimensions and not on the fibrous composition and/or the number of plies. To validate the FE model, the perforation efficiency for papers B and C (Table 1), with a cut distance, c, of 1.9 mm and 4.0 mm, respectively, was simulated. The experimental and simulated results are compared in Figure 6. For these simulations, the FE model considered the same conditions (boundary conditions and fiber orientation) as the experiments with and without perforation. There are some differences between the numerical and experimental results regarding the perforation efficiency (see Figure 6) that could be related to how the failure evolves in the FE model, resulting in higher failure loads (see Equation (1)). Despite these two cases, the FE model showed the same trend, and therefore optimization can be performed using this model (Figure 6). For the 4 mm perforation, the average error between the simulations and experiments was 5.2%, with the error being 8.8% for the 2 mm perforation.

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Figure 5. Perforation efﬁciency behavior as function of perforation line angle.

Figure 6. Experimental and theoretical perforation efficiency results as function of perforation line angle.

The first case considered the optimization of the two parameters, the blank distance, d, and the angle of the perforation line, according to Figure 1, to minimize the tear force. The parameter boundaries used in the GA were 0◦ ≤ α ≤ 55◦ and 0.1 ≤ d ≤ 1.0 mm. Regarding the upper boundary for the perforation line angle, α, the value of 55◦ was chosen to avoid the cut line cross of the upper or the lower edges of the paper model, where the displacement boundary conditions were applied. For the case regarding the optimization of the perforation line angle and the blank distance, the optimum configuration was achieved after 51 generations, with the tear force being in the region of 0.064 N. In the configuration for the minimum tear force, the optimum angle was 0.56◦ , which corresponds to a perforation efficiency of 96.8% and, as expected, d = 0.1 mm. In comparison to a perforation efficiency of 0◦ , in the case of the optimal angle, an increase of 29.3% was obtained. The GA’s best value and mean value over the generations is presented in Figure 7. In this figure, the best value is almost equal through all generations and the mean value converges to the best value after 17 generations. For the case where only the perforation line angle was the variable to be optimized (blank distance d was fixed and equal to 1 mm), the convergence occurred only after 66 generations, and the minimum tear force was 0.394 N. For this case, the angle for the minimum tear force was 0.67◦ , which corresponds to a perforation efficiency of 80.6%. Compared with a perforation efficiency at 0◦ , in the case of the optimal angle, an increase of 7.6% was obtained.

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Figure 7. Optimization evolution of the best value and mean value.

As presented in Figure 8, the best value was almost constant after the 16th generation. On the other hand, the mean value did not converge. For this case, the stop criteria adopted was when the best value between generations was less than the MATLAB® default tolerance. The stresses field for the optimum case, where the blank distance, d, and angle, α, were optimized, are presented in Figure 9, in the increment just before rupture. The normal stress field in the MD (σ11 in Y direction), Figure 9a, shows a stress concentration between the cuts, as expected. As the distance between cuts are only 0.1 mm, the stress concentration is approximately Kt = 21 (regarding the stress in fiber direction, MD), justifying the low rupture force. The same behavior is detected for the other stresses (the CD (σ22 in X direction) in Figure 9b and shear stress (σ12 ) in Figure 9c). Hence, cuttings affect the stress fields in the different directions of the paper plane. In this case, rupture begins at the center of the paper, moving fast towards the left and right edges (see Figure 9d), in the same way as it occurs experimentally in the laboratory. Considering the other case, the optimization regarding only the inclination of the cuts, the stress fields are show in Figure 10. The stress concentration factor is approximately Kt = 4.1 for the MD stress (significantly lower as in the previous case). As in the previous case, the rupture starts at the center of the paper and moves towards the left and right edges (see Figure 10d). Additionally, the simulations regarded the paper as a homogeneous media with no variations in fiber alignment or different concentrations throughout the model. This would not be the case in real paper, and such factors would have an influence on the paper rupture force. Figure 11a shows the MD stress field distribution (σ11 in Y direction) around the cuts with an orientation of 45◦ , and Figure 11b shows the same MD stress field distribution at the beginning of the paper rupture starting at the lower edge towards the center. Due to paper rupture (Figure 11b), stress flows in the non-ruptured region and hence stress is increased (darker green) in this region, while in the ruptured region stress field tends towards zero (darker blue).

Figure 8. Optimization evolution of best and mean value for parameter d.

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Figure 9. (a) Stress ﬁeld MD; (b) stress ﬁeld in CD; (c) shear stress; (d) rupture.

Figure 10. Stress field for the optimum orientation: (a) in fiber direction MD; (b) normal to fiber direction CD; (c) shear stress; (d) rupture for half of the model.

(a)

(b)

Figure 11. (a) Fiber direction stress ﬁeld in MD for cuts at 45◦ ; (b) rupture starting in the lower edge running to the center.

5. Conclusions In general, the results of the FE model simulation analysis support the idea that the value of perforation efﬁciency tends to decrease with an increasing perforation line angle, in agreement with the experimental results. A reduction in the tear force for the toilet paper was pursued using a genetic algorithm considering two different cases. In the ﬁrst case, the blank distance and the angle of the cuts

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were the variables to be optimized and, for this case, the best configuration was achieved with a blank distance of 0.1 mm and a 0.56◦ inclination in terms of the perforation line, achieving an increase of 29.3% in perforation efficiency. Both the best and mean values converged for almost the same value for this case. For the case where the only variable to be optimized was the inclination of the cuts, with the blank distance fixed at 1.0 mm, the genetic algorithm found the best inclination angle to be 0.67◦ , achieving an increase of 7.6% in perforation efficiency, but the average values of the population did not converge. This was due to the complex failure mode of the paper and its kinematics as the damage evolved. Despite the complex failure behavior, the optimum configuration was achieved for both cases (with and without a blank distance fixed at 1.0 mm), and only a small inclination in the perforation line will reduce the tear force, regardless of the rupture progression along the perforation line. Digital twining is an emergent simulation tool that will be commonly used in the near future because it will permit optimization in a digital environment and the subsequent transition to and application in the industrial environment, as proved with this work. The main limitation of this work was that it considered the material to be homogeneous and orthotropic. In fact, the material used experimentally contained heterogeneously distributed fibers, preferentially oriented in the MD. But this macroscale model is accurate enough to simulate different geometries in terms of both the perforation line and the cut itself, such as waves, triangles, etc. Author Contributions: J.C.V.: data acquisition and curation, investigation, writing—original draft, writing—review and editing. A.C.V.: FEM analysis, writing—original draft, simulation supervision, writing—review and editing. M.L.R.: FEM analysis, writing—original draft, simulation supervision, writing—review and editing. P.T.F.: supervision, writing—review and editing. A.P.C.: project supervisor, writing—review and editing. All authors have read and agreed to the published version of the manuscript. Funding: The authors gratefully acknowledge the funding of this work that was granted under the Project InPaCTus—Innovative Products and Technologies from Eucalyptus, Project No. 21874 funded by Portugal 2020 through the European Regional Development Fund (ERDF) in the framework of COMPETE 2020 no. 246/AXIS II/2017. The authors are also very grateful for the support given by the research unit Fiber Materials and Environmental Technologies (FibEnTech-UBI), under the project reference UIDB/00195/2020, and by the Center for Mechanical and Aerospace Science and Technologies (C-MAST-UBI), under the project reference UIDB/00151/2020, both funded by the Fundação para a Ciência e a Tecnologia, IP/MCTES through national funds (PIDDAC). Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Acknowledgments: The authors acknowledge the materials, access to equipment and installations, and all the general support given by The Navigator Company, RAIZ, the Optical Center, Department of Physics, Department of Textile Science and Technology, Department of Chemistry of the Universidade da Beira Interior. Conflicts of Interest: The authors declare no conflict of interest.

References 1. 2. 3. 4. 5. 6.

Olson, S.R.; Hoadley, D.A.; Daul, T.A. Partitionable Paper Towel. U.S. Patent No. US20160345786A1, 1 December 2016. Vieira, J.C.; Fiadeiro, P.T.; Costa, A.P. Converting Operations Impact on Tissue Paper Product Properties–A Review. BioResources 2023, 18, 24. [CrossRef] Ogg, R.G.; Habel, M.A. Perforator Blade for Paper Products and Products Made Therefrom. U.S. Patent No. 5114771, 19 May 1992. Schulz, G.; Gracyalny, D. Method and Apparatus for Pinch Perforating Multiply Web Material. U.S. Patent No. 5755654, 26 May 1998. Hada, F.S.; Baggot, J.L.; Krautkramer, R.E. Method for Perforating Tissue Sheets. WO Patent No. WO 2010/076689 Al, 08 July 2010. ISO 12625-12:2010; Tissue Paper and Tissue Products–Part 12: Determination of Tensile Strength of Perforated Lines–Calculation of Perforation Efﬁciency. International Organization for Standardization: Geneva, Switzerland, 2010.

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7. 8. 9. 10. 11. 12. 13. 14. 15.

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Carvill, J. Mechanical Engineer’s Data Handbook, Butterworth Heinemann, Oxford, United Kingdom. 2015. Available online: http://www.sciencedirect.com:5070/book/9780080511351/mechanical-engineers-data-handbook (accessed on 14 November 2022). Vieira, J.C.; Vieira, A.C.; Mendes, A.d.O.; Carta, A.M.; Fiadeiro, P.T.; Costa, A.P. Mechanical behavior of toilet paper perforation. BioResources 2021, 16, 4846–4861. [CrossRef] Vieira, J.C.; Vieira, A.C.; Mendes, A.d.O.; Carta, A.M.; Fiadeiro, P.T.; Costa, A.P. Toilet paper perforation efﬁciency. BioResources 2022, 17, 492–503. [CrossRef] Almeida, J.H.S.; St-Pierre, L.; Wang, Z.; Ribeiro, M.L.; Tita, V.; Amico, S.C.; Castro, S.G.P. Design, Modeling, Optimization, Manufacturing and Testing of Variable-Angle Filament-Wound Cylinders. Compos. Part B Eng. 2021, 225, 109224. [CrossRef] Kogiso, N.; Watson, L.T.; Gürdal, Z.; Haftka, R.T. Genetic Algorithms with Local Improvement for Composite Laminate Design. Struct. Optim. 1994, 7, 207–218. [CrossRef] Goldberg, D.E. Genetic Algorithms in Search, Optimization, and Machine Learning; Addison-Wesley Pub. Co.: Reading, MA, USA, 1989; ISBN 978-0-201-15767-3. Mäkelä, P.; Östlund, S. Orthotropic Elastic–Plastic Material Model for Paper Materials. Int. J. Solids Struct. 2003, 40, 5599–5620. [CrossRef] Karaﬁllis, A.P.; Boyce, M.C. A General Anisotropic Yield Criterion Using Bounds and a Transformation Weighting Tensor. J. Mech. Phys. Solids 1993, 41, 1859–1886. [CrossRef] Vieira, J.C.; Mendes, A.d.O.; Ribeiro, M.L.; Vieira, A.C.; Carta, A.M.; Fiadeiro, P.T.; Costa, A.P. Embossing pressure effect on mechanical and softness properties of industrial base tissue papers with finite element method validation. Materials 2022, 15, 4324. [CrossRef] [PubMed] ISO 12625-6:2005; Tissue Paper and Tissue Products—Part 6: Determination of Grammage. International Organization for Standardization: Geneva, Switzerland, 2005. ISO 12625-3:2014; Tissue Paper and Tissue Products—Part 3: Determination of Thickness, Bulking Thickness and Apparent Bulk Density and Bulk. International Organization for Standardization: Geneva, Switzerland, 2014.

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Volume 9, Number 3, 2023

A Perspective on the Overarching Role of Hydrogen, Ammonia, and Methanol Carbon-Neutral Fuels towards Net Zero Emission in the Next Three Decades HAIFENG LIU 1, JEFFREY DANKWA AMPAH 1, YANG ZHAO 2, XINGYU SUN 3, LINXUN XU 3, XUELI JIANG 3 & SHUAISHUAI WANG 4,5 Arguably, one of the most important issues the world is facing currently is climate change. At the current rate of fossil fuel consumption, the world is heading towards extreme levels of global temperature rise if immediate actions are not taken. Transforming the current energy system from one largely based on fossil fuels to a carbon-neutral one requires unprecedented speed. Based on the current state of development, direct electrification of the future energy system alone is technically challenging and not enough, especially in hard-to-abate sectors like heavy industry, road trucking, international shipping, and aviation. This leaves a considerable demand for alternative carbon-neutral fuels such as green ammonia and hydrogen and renewable methanol. From this perspective, we discuss the overarching roles of each fuel in reaching net zero emission within the next three decades. The challenges and future directions associated with the fuels conclude the current perspective paper. Contact information: 1 State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China. 2 Tianjin Yuetai Petroleum Technology Ltd., Co., Tianjin 300384, China. 3 Shandong Chambroad New Energy Co., Ltd., Binzhou 256500, China. 4 School of Future Technology, Tianjin University, Tianjin 300072, China. 5 Tianjin Xuandao Technology Co., Ltd., Tianjin 300384, China. Energies 2023, 16, 280. https://doi.org/10.3390/en16010280 Creative Commons Attribution 4.0 International License

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Article 3 – Decarbonisation & Different Fuels

energies Perspective

A Perspective on the Overarching Role of Hydrogen, Ammonia, and Methanol Carbon-Neutral Fuels towards Net Zero Emission in the Next Three Decades Haifeng Liu 1 , Jeffrey Dankwa Ampah 1, * , Yang Zhao 2 , Xingyu Sun 3 , Linxun Xu 3 , Xueli Jiang 3 and Shuaishuai Wang 4,5 1 2 3 4 5

State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China Tianjin Yuetai Petroleum Technology Ltd., Co., Tianjin 300384, China Shandong Chambroad New Energy Co., Ltd., Binzhou 256500, China School of Future Technology, Tianjin University, Tianjin 300072, China Tianjin Xuandao Technology Co., Ltd., Tianjin 300384, China Correspondence: jeffampah@live.com or jeffampah@tju.edu.cn

Abstract: Arguably, one of the most important issues the world is facing currently is climate change. At the current rate of fossil fuel consumption, the world is heading towards extreme levels of global temperature rise if immediate actions are not taken. Transforming the current energy system from one largely based on fossil fuels to a carbon-neutral one requires unprecedented speed. Based on the current state of development, direct electriﬁcation of the future energy system alone is technically challenging and not enough, especially in hard-to-abate sectors like heavy industry, road trucking, international shipping, and aviation. This leaves a considerable demand for alternative carbon-neutral fuels such as green ammonia and hydrogen and renewable methanol. From this perspective, we discuss the overarching roles of each fuel in reaching net zero emission within the next three decades. The challenges and future directions associated with the fuels conclude the current perspective paper. Keywords: carbon-neutral fuels; decarbonization; hydrogen; ammonia; methanol Citation: Liu, H.; Ampah, J.D.; Zhao, Y.; Sun, X.; Xu, L.; Jiang, X.; Wang, S. A Perspective on the Overarching Role of Hydrogen, Ammonia, and

1. Introduction

Methanol Carbon-Neutral Fuels

As the catalyst for economic expansion and urbanization, industrialization has led to the substantial development of several sectors of the global economy in conjunction with a growth in world population and wealth [1,2]. The world population is projected to grow to 9.9 billion in 2050 from 7.8 billion in 2020, creating an environment where energy requirements increase by 80% [3,4]. The historical patterns of growth in human population, activities, and energy demands have had a huge inﬂuence on the environment. The Mauna Loa Observatory in Hawaii’s latest data suggests that the carbon dioxide (CO2 ) in the atmosphere as of 2022 had exceeded 415 ppm, which represents approximately a 14% increase in less than 25 years when compared to the levels in 1997 [5]. It has been projected that by 2050, greenhouse gas (GHG) emissions will increase by 50%, mainly as a consequence of the expected 70% increase in energy-related CO2 emissions [4,6]. At the current rate of emission increase, the carbon cycle is likely to be pushed out of its dynamic equilibrium, causing an irreversible change to the climate system [7]. Against this backdrop, several rounds of climate negotiations to tackle climate change have been carried out by the international community. The adoption and signing of a series of international treaties such as the Kyoto Protocol and the 2015 Paris Agreement has led to real progress toward national climate change mitigation commitments. The Paris Agreement for instance aims to limit global warming to 1.5 °C above pre-industrial levels [8]. However, compared to where current policies stand, a median warming of 2.6–3.1 degrees Celsius by 2100 is more likely even if all parties were to deliver on their climate pledges [9].

towards Net Zero Emission in the Next Three Decades. Energies 2023, 16, 280. https://doi.org/10.3390/ en16010280 Academic Editor: Attilio Converti Received: 7 December 2022 Revised: 23 December 2022 Accepted: 23 December 2022 Published: 27 December 2022

Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

Energies 2023, 16, 280. https://doi.org/10.3390/en16010280

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Thus, more long-term stringent measures have to be put forward. According to the Intergovernmental Panel on Climate Change (IPCC), the 1.5 °C goal requires a global realization of net zero CO2 emissions by 2050—a goal collectively termed “reaching carbon neutrality”. Carbon neutrality refers to the balance between CO2 emissions and absorptions within a speciﬁc period to achieve “net zero emissions of carbon dioxide” [10]. Carbon neutrality means the output of CO2 is offset by other approaches and thus has neutral effects on the environment. Today, a total of 194 countries have joined the Paris Agreement [11]. Countries like the United Kingdom, Germany, Canada, France, South Africa, South Korea, and Denmark have pledged to reach carbon neutrality by 2050, Iceland and Sweden by 2040 and 2045, respectively, China by 2060, India by 2070, and more countries are expected to make similar pledges in the near future [12,13]. The development of carbon-neutral fuels is very crucial in reaching carbon neutrality, especially in decarbonizing the major energy-consuming sectors such as heavy-duty transport, power, industry, etc. [14–16]. Carbon-neutral fuels are carbon-based fuels that do not increase the atmospheric CO2 when combusted. A net zero amount of atmospheric carbon is achieved from the combustion of these fuels in the sense that they are typically produced with CO2 as a key component in the process—implying that there is no net gain of carbon in the atmosphere. There are several carbon-neutral fuels and all these fuels are important to the realization of a net zero future. However, the remaining discussions in this perspective paper are limited to green hydrogen, green ammonia, and renewable methanol. There are several existing reviews on their production technologies and pathways such as hydrogen [17–19], ammonia [20–22], and methanol [23–25]. Despite the key contributions of such reviews, there is a limited holistic summary of the role of these fuels in reaching a net zero future. Our current perspective is thus developed to provide a brief overview of the interconnected roles of all three fuels. These are arguably the three most often considered carbon-neutral fuels to signiﬁcantly contribute to the realization of carbon neutrality within the next three decades, especially in hard-to-abate sectors like long-range transport, energy-intensive industry, and parts of residential heating. The coupling of these sectors with the power sector through the production and consumption of these fuels helps solve one of the most challenging tasks with renewable electricity generation (i.e., matching time of generation to time of load consequently leading to energy curtailment), especially from intermittent sources such as solar and wind energy. The technologies for their production stage to end-use are well understood and have been around for quite some time albeit with certain inherent challenges such as commercialization and large scale-up. Undoubtedly, these three carbon-neutral fuels considered in this perspective have a crucial role to play in reaching the 1.5 °C target by mid-century, and these roles and potential applications will become apparent in the subsequent sections. Figure 1 highlights the energy transition from today’s fossil fuel-dominated system to tomorrow’s net zero carbon emissions system powered mainly by renewable energies and carbon-neutral fuels.

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Figure 1. Carbon neutral fuels in future net zero carbon emissions.

2. Role and Prospects of Carbon-Neutral Fuels in the Future Energy System 2.1. Green Hydrogen The International Energy Agency (IEA) reports that in 2020 the demand for hydrogen was approximately 90 million metric tons, with approximately 80% being used as pure hydrogen and the remainder being mixed with carbon-containing gases for steel manufacturing and methanol production [26]. In a scenario where net zero emissions are targeted, the demand for hydrogen is projected to increase to 530 million metric tons by 2050, a nearly six-fold increase from the 2020 level [27]. Green hydrogen is a synonym for renewable energy produced through water electrolysis using renewable energy sources. Currently, green hydrogen accounts for only 0.1% of global energy production [28]. However, since the scale-up of green hydrogen is crucial for achieving net zero emissions by 2050 and limiting global temperature to 1.5 °C, green hydrogen, and its derivates could be responsible for supplying up to 12% of final energy consumption by 2050. Therefore, 63% of final energy consumption could be realized from both green hydrogen and electricity alone [29]. By 2023, investment in green hydrogen production could exceed $1 billion due to the fall in renewable power and electrolyzer costs as a result of several governmental interventions and policies regarding green hydrogen [30]. For example, the US Department of Energy is putting up $100 million for research and development of green hydrogen. By 2030, the European Union will have invested $430 billion in green hydrogen to aid in the realization of its Green Deal. Chile, Japan, China, Germany, and Australia are all making huge investments in green hydrogen [31]. Based on several assessments of different agencies such as BloombergNEF [32], Energy Transition Commission [33], Hydrogen council [34], IRENA [29], and IEA [35] as compiled by the authors of [36], it is clear that 2050 s hydrogen will be mainly green and blue hydrogen (hydrogen production from fossil fuels with carbon capture and storage (CCS) technologies), with the former contributing more than half of total production (Figure 2). Both are carbon-neutral pathways but CCS is yet to be widely commercial and requires significant scale-up as well.

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Figure 2. Hydrogen production by source by 2050 according to different agency assessments. Based on data from Ref. [36].

Hydrogen can help tackle various critical energy challenges regarding future energy transition [37,38]. Most importantly, it offers an enabling environment to decarbonize some difficult-to-decarbonize sectors including heavy industrial sectors such as steel, cement, chemicals, and aluminum, and long-distance sectors such as shipping, aviation, and long-distance road transport. Together these account for about 30% (10 Gt) of all emissions but the share could rise reaching 16 Gt by 2050 as other sectors such as power get decarbonized [39,40]. In addition, there exist several prominent studies advocating for a 100% renewable energy future—however, the immediate challenge with a 100% renewable energy scenario with complete direct electrification concerns the intermittent nature of solar and wind sources which cannot be overlooked, leading to power curtailment. Against this concern, the introduction of Power-to-X (P2X) provides a key solution to making 100% renewable energy possible. Hydrogen aids in balancing the intermittent supply and providing the required system flexibility through the coupling of various sectors. Through the use of electrolyzers, excess electricity that would have been otherwise curtailed could potentially be converted to hydrogen and re-injected into the network as electricity during power deficits or delivered to other sectors such as industry, transport, or residential. Of the available energy storage technologies currently available, P2X storage presents the most overall optimal long-term and carbon-free seasonal storage. The timespan and power capacity needed to address seasonal imbalances cannot be handled alone by the likes of batteries, supercapacitors, and compressed air. Pumped hydro storage, on the other hand, can provide long-term and large-scale energy storage but it is characterized by geographical restrictions for the remaining untapped potential and its global output capacity of 170 GW is about only 2% of the total installed electricity capacity in the world. Another role of hydrogen concerns its ability to supply energy to areas where energy is conventionally imported. To wit, electricity can be produced in areas with high levels of solar and wind energy, and through P2X, converted to hydrogen or hydrogen-based fuels and transported to import

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regions. Huge energy losses are incurred during the transportation of electricity over longer distances but a 100% efﬁcient pipeline transport of hydrogen is feasible—making hydrogen an economically attractive alternative for transporting large-scale renewable energy over long distances. In summary, hydrogen and its derivatives will allow high penetration rates of variable renewable energies, leading to a signiﬁcant reduction of CO2 emissions (avoiding up to 60 Gt CO2 in 2021–2050, a 6.5% of total cumulative emission reduction [41]), playing a crucial role in hard-to-decarbonize sectors, and functioning as a catalyst for sector coupling (Figure 3).

Figure 3. Role of green hydrogen in a carbon-neutral future.

2.2. Green Ammonia Ammonia as the basis for all mineral nitrogen fertilizers forms the bridge between the nitrogen in the air and the foods we consume. The production of ammonia, however, is far from being clean. The nitrogen is captured from the air but almost all of the hydrogen required is currently produced from fossil fuels. Thus, the conventional production of ammonia is a very carbon-intensive process. The process accounts for 1.3% of global CO2 emissions from the energy system [42] of which 80% originate from the hydrogen production stage [43]. This provides room for the decarbonization of ammonia synthesis where hydrogen production can be achieved through water electrolysis using low-carbon electricity sources (green hydrogen) to react with nitrogen from the air to form green ammonia. This green process of ammonia synthesis could potentially reduce the carbon footprint of conventional ammonia production from 1.6 to 0.1 tCO2 /tNH3 which can further reach near zero in the future with technological advancement [44]. Ammonia has an important role to play in the carbon-neutral future scheduled for the next three to four decades. As mentioned earlier, the 1.5 °C goal will lead to significant growth in green hydrogen demand, and the transport of green hydrogen from one region to another will become a common feature in this future transition. However, it is challenging to store, handle, and transport hydrogen. Though this is achievable with compressed or liquified hydrogen at −253 °C, the process requires huge capital investments, energy (for cooling), energy losses due to cooling, and poses safety concerns. Alternatively, it is safer, easier, and cheaper to transport and store hydrogen in the form of ammonia. This is because, relative to volume, liquid hydrogen has a lower energy density than ammonia. Also, at −35 °C, ammonia is already in a liquified state, and can then be easily and safely transported. In addition, the required infrastructure for transporting ammonia is already in place for decades as millions of tons of ammonia are annually transported by sea. About 20 Mt of ammonia (out of the 185 Mt of production) were globally traded in 2020 [42].

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In the coming years, several ammonia projects are scheduled to come online with an expected minimum of 3 Mt electrolytic ammonia production for conventional uses, considering projects that were announced as of June 2021 (Figure 4a). In the Sustainable Development Scenario (SDS) of IEA assessment, the ammonia production via electrolysis will play a crucial role. By 2050, electrolytic ammonia will account for about 20% of global ammonia production (a rise from the current <0.01%), with Europe, India, and China being the main regions of green hydrogen production (Figure 5). The green ammonia in the global output according to IEA’s Net Zero Emission (NZE) scenario by 2050 has higher shares than SDS. In the NZE scenario, ammonia for power generation could reach 85 Mt as opposed to a near zero share in 2020 (Figure 4b). Furthermore, due to the emission reduction targets in the shipping sector (cut maritime emissions by at least 50% by 2050) and sulfur content limits of marine fuels, ammonia which is considered to be the “destination fuel” will be an important shipping fuel. As seen in Figure 4c, the share of total fuel consumption of ammonia in national and international maritime shipping could reach around 25% in the SDS and around 45% in the NZE scenario by 2050 [42].

Figure 4. (a) Pathways to near zero emission ammonia production (current and announced); (b) ammonia demand by sector (SDS: sustainable development scenario; NZE: net zero emissions); (c) shipping sector ammonia demand [42] (Published under license CC BY 4.0).

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Figure 5. Various ammonia production pathways and scenarios in major ammonia-producing regions (STEPS: Stated Policies Scenario) [42] (Published under license CC BY 4.0).

According to IRENA’s assessment, the global transition towards the 1.5 °C goal could potentially lead to a 688 Mt ammonia market which is about 4 times larger than the existing market, and green ammonia will dominate the global ammonia market. Over the next 30 years, 566 Mt of new green ammonia production must come on-stream. This will constitute about 20% of the global green hydrogen market [29]. The future green ammonia market opens up channels for the penetration of high shares of renewable generation capacity. In other words, the interaction between renewable power and ammonia sectors will signiﬁcantly increase the renewable electricity generation capacity due to the increased demand for green hydrogen in the synthesis of green ammonia. With the estimated 566 Mt of green hydrogen by 2050, 2.3 TW of renewable generation would be required which is nearly 30% of the current global cumulative electricity capacity [45]. From Power-to-ammonia (P2A) concepts, surplus electricity from variable renewable energy sources such as wind and solar can be converted into green ammonia, which can provide long-term storage. As seen in Figure 6, P2A provides better seasonal storage and capacity than other alternatives with similar purposes. In the future energy system, therefore, P2A will provide the required balance to the grid that would have otherwise been overloaded and unstable (due to the mismatch between high renewable generation and demand) by minimizing power curtailment.

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Figure 6. Energy storage capacity and discharge time of different storage technologies [44] (published under the terms of the Creative Commons CC-BY license).

2.3. Renewable Methanol One of the most popular and important liquid chemicals used in producing daily products, including plastics, paints, cosmetics, and fuels, is methanol. Methanol produced from sustainable biomass (bio-methanol) or by reaction between captured CO2 and renewable electricity-based hydrogen (e-methanol) is typically referred to as renewable or green methanol, and it is a low carbon and net carbon neutral liquid chemical and fuel. Renewable methanol reduces CO2 and NOx emissions by 95% and up to 80%, respectively, and eliminates SOx and PM emissions in contrast to traditional fuels [46]. Each year, approximately 98 Mt of methanol is produced, almost all of which is via fossil fuels (natural gas or coal). The amount of renewable methanol (mostly bio-methanol) produced yearly is less than 0.2 Mt. Life cycle emissions show that around 0.3 Gt of CO2 production per year is recorded from the conventional methanol production and use, representing about 10% of the total chemical sector’s emissions [47]. More than 80 renewable methanol projects around the world are being tracked by the Methanol Institute, and they are projected to produce annually at least 8 MMT of renewable methanol by 2027. In the next ﬁve years, the capacity of individual renewable methanol plants is expected to rise from 5000–10,000 tonnes of methanol per year to 50,000–250,000 tonnes per year (see Figure 7a,b) [46]. Considering ongoing rates, methanol production could rise to 500 Mt per year by 2050 from today’s ~100 Mt. If the 500 Mt of methanol is sourced from fossil fuels, CO2 emissions of 1.5 Gt will be released per year. To meet the 2050 production needs for methanol while adhering to net zero emission targets, about 80% of this production will come from renewable methanol (135 Mt and 250 Mt from bio-methanol and e-methanol, respectively (see Figure 8) [47].

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Figure 7. (a) Countries by the count of existing renewable methanol projects; (b) projected renewable methanol production capacity by start-up year. Based on data from Ref. [46].

Figure 8. Production capacity of fossil and renewable methanol by 2050. Based on data from Ref. [47].

Renewable methanol cannot only be a fuel for transport applications [48,49] and feedstock in the chemical industry but it can decisively promote the decarbonization of hard-to-abate industrial sectors. Additionally, a local and CO2 -neutral closed-loop system is created for the integration of renewable methanol production into existing industrial facilities such as CHP plants or cement and steel production plants. As more countries seek to ban or limit internal combustion engines (ICE) in line with the 1.5 °C goal, e-methanol could help cut down the emissions during the transition to electric mobility options, vehicle operations for instance. Since it is possible to blend methanol with gasoline and use it in ICEs, renewable methanol provides a carbon-neutral transport alternative. China for instance already piloted M85 and M100 methanol vehicles in 2012, and by 2025, the ﬂeet of M100 vehicles in China could reach 50,000 consuming more than 500,000 tonnes of methanol [50]. The use of direct methanol fuel cells also provides the possibility of running 100% methanol in any type of electric vehicle. Renewable methanol is likely

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to play an important role in the future decarbonization of the shipping sector [51]. For instance, since 2016 seven oceangoing vessels have been operating equipped with dual fuel, two-stroke engines, which can run on methanol, heavy fuel oil (HFO), marine diesel oil (MDO), or marine gas oil (MGO) [52]. Brynolf et al. [53] showed that the environmental impact of renewable methanol is relatively lower than HFO and other alternatives such as liquified natural gas (LNG), liquified biogas, and fossil methanol. A transition assessment of DNV-GL shows that the uptake of at least three or four different carbon-neutral fuels in the shipping sector could account for 60–100% of shipping energy use by 2050. The tightening of shipping emission regulations in the next two to three decades could ensure that fleets shift directly to carbon-neutral methanol or ammonia while other low-carbon alternatives such as bio-MGO, e-MGO, bio-LNG, e-LNG function as drop-in fuels for existing ships [54]. Within the P2X concepts, methanol is a hot topic and has the potential to be one of the solutions to use and store large-scale renewable electricity as seen in Figure 6. The requirement of electrolyzers in producing the needed hydrogen in the synthesis of e-methanol opens up opportunities to integrate more renewable generation into the future power sector (i.e., matching time of generation to time of load). Therefore, the interactions between the renewable power and methanol (e-methanol) sector could lead to higher shares of intermittent renewable energy resources in a net zero emission world within the next three decades. Last but not least, methanol can play a significant role as a green hydrogen energy carrier. Similar to the case of ammonia, the energy density of methanol is very interesting for transporting green hydrogen from one region to another for example from Australia to Asia. This is feasible as the supply infrastructure for transporting methanol is already in place due to the existing supply of huge quantities of methanol around the world annually. Figure 9 shows the key roles green ammonia and methanol can play in tomorrow’s carbon-neutral world.

Figure 9. Role of green ammonia and methanol in a carbon-neutral future.

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3. Application of Carbon-Neutral Fuels (Power, Transport, Heat) As discussed above, carbon-neutral fuels have critical roles to play in the realization of carbon neutrality in the next three decades. Today, they are already in application in several sectors of the energy system as summarized in Figure 10. In terms of power generation, these fuels offer cleaner pathways by using technologies such as fuel cells, reciprocating engines, or gas turbines to replace high-carbon fuels. Hydrogen can be utilized in fuel cells and turbines for the generation of power and heat. There are several existing and planned hydrogen-based combined heat and power (CHP) projects. At NREL’s Flatinos Campus, a fuel cell generator as part of the ARIES MW-scale hydrogen system is being designed and commissioned. The flexible system comprises a 1.25 MW PEM electrolyzer, a 600 kg H2 storage system, and a 1 MW fuel cell generator. The platform is designated to demonstrate direct green hydrogen generation, energy storage, power production, and grid integration at MW scale [55]. Across the world, more than 800 MW of large stationary fuel cell systems (rated power >200 kW) have been installed for distributed generation and CHP applications, with the largest shares of installation located in the US and South Korea. More than 4100 fuel cell units for CHP applications have been installed in Europe and a 1.4 MW stationary fuel cell powerplant is the largest in Europe. The transport sector alone is responsible for 20% of the global primary energy demand, and about 96% of this demand is met with petroleum [56]. Due to the progressive growth of fossil fuel consumption, the sector was responsible for 37% of CO2 emissions from end-use sectors in 2021 [57]. Sectors such as aeronautics, long-haul road, maritime transport, and railways require highly dense fuels and the direct electrification of these sectors with batteries or grid is challenging. The range, capacity, and refueling time of batteries do not make them suitable for these sectors but carbon-neutral fuels, on the other hand, meet the fuel requirement of these hard-to-abate transport sectors and they can directly replace the fossil fuels or indirectly electrify these sectors. The International Maritime Organization (IMO) has plans to reduce shipping carbon intensities by an average of 40% by 2030 and by 70% by 2050 and cut maritime emissions by at least 50% by 2050 in reference to 2008 levels. In addition, as of January 2020, the global sulfur content of marine fuels has been limited to 0.5 wt% [38,58]. These targets have created an important opportunity for the penetration of carbon-neutral fuels in the shipping sector. In the shipping sector, for example, ammonia’s popularity is growing significantly. The world’s first ammonia-based fuel cell for shipping is being developed by the Fraunhofer Institute in collaboration with 13 European consortium partners as part of the ShipFC project [59]. The project comprises an offshore vessel retrofitted with a large 2 MW ammonia fuel cell that will allow it to sail 100% on ammonia for up to 3000 h per year [60]. Similarly, green ammonia is being developed in the Ammonia Zero Emissions Project (AMAZE) as a substitute ship engine fuel. The project was launched in early 2022 by Bergen Engines to develop technology for a fuel-flexible ICE with green ammonia as the primary fuel [61]. Net carbon-renewable methanol will meet IMO’s goal of reducing GHG emissions by 50% by 2050. By using methanol as a marine fuel compared to diesel, emissions of SOx , NOx , and PM reduce by 99%, 60%, and 95%, respectively [46]. The application of carbon-neutral fuels in road transport is also gaining momentum in recent years. China has a goal to produce between 100,000 and 200,000 tons of green hydrogen annually and to have around 50,000 hydrogenpowered vehicles on the roads by 2025. Currently, M100 (100% methanol) vehicles are in operation in some countries with China having the largest share of such vehicles. In Italy, methanol-derived fuels such as A20, methanol (15%)-bio-ethanol (5%)-gasoline blends are being trialed. The US has for some time been using methanol regularly in motorsports, and Iceland is fuelling a fleet of cars with renewable methanol [46]. Methanol fuel cells do not only substitute fossil fuels and reduce both CO2 emissions and fuel consumption but they are also designed to ensure long-range, fast refueling, zero harmful emissions, and lower costs. The range of battery electric vehicles can be extended from 200 km to over 1000 km with methanol fuel cells. An eco-friendly alternative fuel for heating is methanol. As a substitute fuel for cookstoves and boilers, methanol has been adopted in some parts

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of Tanzania, India, Nigeria, and China. Industrial Methanol is used to heat buildings in Shanxi, dry tea in Darjeeling, and fuel cookstoves in restaurants in Shanghai. Methanol boilers surpass coal in terms of restricting pollution, as they reduce overall emissions of PM, SOx , and NOx by at least 75% [46].

Figure 10. General production pathways of various carbon-neutral fuels and their key sector of application.

4. Challenges, Future Perspectives, and Conclusions The three fuels presented in this perspective have a critical role to play in the world’s quest of reaching carbon neutrality by mid 21st century. However, there are still some challenges that pose a potential threat to the realization of net zero carbon emissions via carbon-neutral fuels. Some of the common barriers to the up-scaling of all three fuels are summarized as follows. The main and universal challenge facing all three fuels concerns their investment costs when compared to fossil fuel-based processes. For instance, the price of renewable hydrogen is at least two times more expensive than that of grey hydrogen. One of the critical reasons for the discrepancies in fuel pricing between carbon-neutral fuels and their traditional counterpart stems from the fact that the latter is well-developed and already at hundreds of MW to GW capacities, and as such can negotiate for feedstocks at lower prices whiles most carbon-neutral fuels are still in kW to low MW capacities. Furthermore, the price variations between fossil-based and renewable-based fuels can be attributed to the high initial investment of renewable energy projects and the requirement for large electricity for the production of carbon-neutral fuels. Going forward, the cost of renewable energy technologies and clean electricity generation should decrease whiles simultaneously making the fossil-based pathways economically unattractive to pursue. Mechanisms such as carbon pricing, phasing out fossil fuel subsidies, private sector involvement in renewable energy development, and the establishment of production tax credits and investment tax credits for promoting wind and solar energy projects, respectively, could be instituted to make renewable electricity-based fuels cost-competitive against their fossil fuel alternatives. Since all three carbon-neutral fuels depend largely on renewable electricity (except biomethanol), there is the issue of the intermittent and ﬂuctuating nature of sources such as wind and solar energy. The power plants for producing carbon-neutral fuels need to be in operation frequently, and as such future developments should consider providing a stable and dependable electrical grid via the combination of both dispatchable and nondispatchable sources of electricity as well as storage. To build a huge global market for carbon-neutral fuels, huge investments are required to develop a range of infrastructure for transportation and storage, especially in the case of hydrogen. There is a need to establish a well-functioning infrastructure that can handle the fuels after production, transport, and

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cost-effectively store them. The lack of sectorial coupling is another issue that curtails the upscale of carbon-neutral fuels. Currently, the fuels are most applied in the industrial sector, and to rapidly achieve the 1.5 °C goal, they should also be widely used in sectors where their application is currently limited such as transport, heating, and power generation. The coupling of the various energy sectors creates additional demand for these fuels and maximizes the technical penetration of solar and wind energy without causing challenges to the grid network. In other words, the Power-to-X through the interactions of the different sectors will create the needed balance in the grid network at high shares of solar and wind electricity generation. At the moment, it is also difﬁcult to tell the difference between fossilbased fuels and their carbon-neutral counterparts—for instance, grey and green hydrogen will look the same to consumers after production. Immediate regulation, standardization, and certiﬁcation could help resolve this challenge. Figure 11 summarizes some critical challenges facing the development of carbon-neutral fuels.

Figure 11. Critical challenges facing the development of carbon-neutral fuels.

In summary, the current paper presents a brief perspective on three different carbonneutral fuels i.e., green hydrogen, green ammonia, and renewable (green) methanol which are the ‘hot’ fuels for tomorrow’s energy system in light of climate goals. We have shown that these fuels have a critical role to play if net zero carbon emissions are to be possible by mid 21st century. Their most important contributions will be witnessed in hard-to-decarbonize sectors like long-range transport, energy-intensive industry, and part of residential heating where it is difficult to directly electrify. The realization of carbon neutrality via carbon-neutral fuels is possible but only after some critical challenges are resolved, especially in making the entire process cost-effective and competitive against existing processes that are dominated by fossil fuels. Author Contributions: Conceptualization, H.L.; writing—original draft preparation, J.D.A.; writing—review and editing, Y.Z. and X.S.; visualization, J.D.A.; supervision, H.L.; validation, S.W.; project administration, L.X. and X.J.; funding acquisition, H.L. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by National Natural Science Foundation of China, grant numbers 52176125 and 51921004. Data Availability Statement: Not applicable. Acknowledgments: The authors would like to acknowledge the financial support to the research provided by the National Natural Science Foundation of China through the Projects 52176125 and 51921004. Conflicts of Interest: The authors declare no conflict of interest.

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PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY TE INTERNATIONAL®

Volume 9, Number 3, 2023

Data-driven Predictive Maintenance: a paper making case DAVIDE RAFFAELE & GUENTER ROEHRICH Condition monitoring together with predictive maintenance of bearings and other equipment used by the industry avoids severe economic losses resulting from unexpected failures, greatly improves the system reliability and allows a more efficient usage of human experts’ time. This paper describes a predictive maintenance system, based on a data science approach. The system was developed and tested on a single real paper machine, and then verified with multiple external validations. Results show a proper behaviour of the approach on predicting different machine states with high accuracy. Contact information: Mondi Group Marxergasse 4a 1030, Vienna, Austria https://www.researchgate.net/publication/373160794 non-peer-reviewed pre-print (August 2023)

Page 1 of 7

Article 4 – Predictive Maintenance

Data-driven Predictive Maintenance: a paper making case Davide Raffaele

Guenter Roehrich

Mondi Group Marxergasse 4a 1030, Vienna, Austria

davide.raffaele@mondigroup.com

Guenter.Roehrich @mondigroup.com

ABSTRACT Condition monitoring together with predictive maintenance of bearings and other equipment used by the industry avoids severe economic losses resulting from unexpected failures, greatly improves the system reliability and allows a more efficient usage of human experts’ time. This paper describes a predictive maintenance system, based on a data science approach. The system was developed and tested on a single real paper machine, and then verified with multiple external validations. Results show a proper behaviour of the approach on predicting different machine states with high accuracy.

Keywords Predictive maintenance, Data Science, Industry 4.0, Vibration measurements, Data Analysis, Bearings, Condition Monitoring.

1. INTRODUCTION Predictive maintenance, also known as "on-line asset monitoring", or "smart condition-based maintenance", involves the intelligent monitoring of equipment to prevent future failures and has received growing attention in research. In the past decade, predictive maintenance has advanced from relying on visual inspection methods to automated ones that leverage advanced signal processing techniques such as pattern recognition, machine learning, neural networks, and fuzzy logic. These automated methods offer viable solutions for various industries by detecting and collecting sensitive information from equipment, where human observation may fall short [1] [2]. Integrated sensors and predictive maintenance can work together to prevent unnecessary equipment replacement, reduce machine downtime, pinpoint the root cause of faults, and ultimately save costs and improve efficiency. Predictive maintenance shares similarities with preventive maintenance, as both involve scheduling maintenance activities in advance to avoid machine failures. However, unlike traditional preventive maintenance, predictive maintenance schedules activities based on data collected from sensors and analysed by algorithms. [3], [4] [1]. Traditionally, predictive maintenance aims to schedule interventions on a machine based on health condition predictions derived from high frequency data collected by sensors. However, in the paper industry, paper machines require to stop production at regular intervals for technical reasons (e.g. felts changes), which creates a great opportunity for preventive maintenance actions. In this context, predictive maintenance is no longer a regression problem: when to schedule maintenance? It becomes a classification problem: what parts of a machine should be exchanged at a given point in time? We focus on one type of machine part: rolling-element bearings. Bearing products are important components of paper machine as

their break can cause significant production losses and even damages to the machine. The problem is how to predict the state of a bearing using vibration data. In predictive maintenance three kinds of approaches can be distinguished [1]: 1) Data-driven approach, 2) Model-based approach, and 3) Hybrid approach. While the data-driven approach uses historical data to learn patterns and system behaviour. The model-based approach is expert-driven and has the ability to incorporate physical understanding of the target product, relying on the analytical model to represent the behaviour of the system. A hybrid approach data combines datadriven as week as model-based approach is also found in the literature [5] . With the exponential increase of data being collected and available in production environment, the use of data-driven approach is increasing [6], [7] and will be the focus of this paper. The authors intend to build upon the aforementioned ideas and present a method for early-stage detection of degradation in bearings. To increase efficiency and prevent downtimes it is crucial to decide which bearings to replace at a given point in time. The contributions in this paper primarily address the application of data science approaches to real-world data related to paper machines on the field, the high level of accuracy on predictive state of the bearings and, moreover, the specificity of the application for the papermaking industry. This paper is organized as follows: Section 2 gives an overview of predictive maintenance approach used in literature. Section 3 provides an introduction to domain knowledge of bearings and their faults modes. Section 4 provides a sound foundation for the methodology followed in this paper. Section 5 demonstrates the experimental results based on the real use case under which predictive maintenance has been implemented and tested. Finally, Section 6 provides a reflection on the results that have been achieved and compares them to the current state of the literature.

2. RELATED WORK Paper industry has an extensive literature on data-driven methodologies, but it rather focusses on virtual sensors [8] [9] [10] and not on predictive maintenance. For this reason, the authors intend to hold the rest of the section industry-agnostic. Bearing degradation modelling methods can be categorized into two groups: continuous degradation, focused on building a single model to capture the degradation, and discrete degradation stage models, typically classification models that predict degradation changes over time.

Discrete degradation stage modelling is faced with the challenge of identifying multiple degradation stages. Methods such as hidden Markov models [11] or Mahalanobis Taguchi System [12] are used to characterize bearing degradation stages based on observations. These approaches consider low dimensional feature vector inputs since model parameter estimation in high dimensional settings is challenging [13]. Low dimensional inputs reduce model predictive power, as information is lost when bearing vibration signal is embedded intpo lower dimensions. Our work is different from these models as we attempt to build a decision-support system that can provide a health assessment of each bearing as continuum, which serves as feature required for ranking-comparison of bearing status at any given moment. The continuous degradation is often referred as health index [14] and is typically calculated from a single feature, or a combination of features derived from bearing vibration data and fused together, using e.g., RMS [15], kurtosis values [16], power densities [17], or statistical methods [18]. A fault is detected when the health index exceeds a predefined threshold value. This is a critical decision in the system, yet setting the threshold value is not a trivial task. The work describes this body of literature and builds upon the aforementioned methods.

3. DOMAIN KNOWLEDGE The Cross Industry Standard Process for Data Mining (CRISP-DM) is a widely recognized model for data mining, which emphasizes the importance of having technical knowledge to effectively classify the results of a data science approach and its underlying process [19]. For instance, when dealing with bearing faults, having an understanding of the technical background of bearings is crucial for properly identifying, assessing and characterizing different types of faults that may occur. Therefore, this section provides an in-depth exploration of the structural components of a bearing and the various types of faults that can manifest within the bearing system Bearings consist of four essential components, namely the rolling elements, cage, inner ring, and outer ring. Rolling elements, typically steel balls, are located between the outer and inner rings and are responsible for reducing friction between moving parts as shown in Figure 1. The cage maintains the relative positions of the rolling elements, reducing friction and therefore preventing them from colliding or rubbing against each other. While a bearing fault can arise from any of the four components, approximately 90% of faults are associated with the inner and outer rings [20]. This may be attributed to the permanent stress that the rings are subjected to, whereas the rolling elements are in continuous motion, causing their contact area to continually change. In addition, the cage does not bear any load [21]. Fault can occur in three different forms [22]: A) Single-point defects, B) Multiple-point defects, C) Distributed faults. In the event of a defect occurring at a singular location on a bearing, all other components of the bearing remain in sound condition, with the exception of the specific point where the defect arises, resulting in an amplified magnitude of the characteristic frequencies associated with the particular fault type. Examples of this fault classification include the emergence of pits, spalls, and cracks on the outer and inner ring, balls, and cage of the bearing. The majority of contemporary research articles are primarily on the investigation of single point defects [23].

The term multiple-point defects refers to the occurrence of more than one single point defect in a bearing. This type of fault results in variations in the magnitude of the frequency in the frequency domain. The position of the defects can either reinforce or oppose these frequency variations [24].

Figure 1 - Structure of a rolling bearing Finally, distributed faults typically result from contamination, loss of lubrication, or coupling misalignment. These faults lead to a roughening of the bearing surface, also known as "generalized roughness". Unlike multiple-point defects, distributed faults cannot be decomposed into distinct single-point defects. As a consequence, characteristic frequencies may not be readily detectable, or they may not exist at all [25].

4. METHODOLGY The basic scheme of a machinery health prognostic program is composed of following technical processes [26]: data acquisition, health indicator (HI) construction, health stage (HS) division.

4.1 Data acquisition Data acquisition is the procedure of acquiring and recording various types of monitoring data from a multitude of sensors that are installed on the equipment under surveillance. This crucial process serves as the initial step in machinery prognostics, and provides fundamental condition monitoring information that forms the basis for subsequent analysis. A data acquisition system consists of several components, including sensors that measure and capture data, data transmission devices that transmit the data to a storage location, as well as data storage devices that store the captured information. In order to build a predictive maintenance model, the most important data to acquire has to capture breakdown events of the equipment. However, acquiring high-quality run-tofailure data for academic research on machinery remains a challenge due to several reasons [26]. Firstly, machinery undergoes a prolonged degradation process from a healthy state to failure, which can last several months or even years. Gathering complete run-to-failure data during this extended period can be both timeconsuming and expensive. Secondly, practical considerations prohibit allowing machinery to run to failure, as unexpected failure can result in machine breakdown or catastrophic accidents. This makes it difficult to capture run-to-failure data in industrial settings. Thirdly, machinery, such as gearboxes, engines or bearings, operates in harsh environments that introduce significant external interferences to monitoring data, thereby reducing its quality. Fourthly, much monitoring data are collected during out-of-service periods, such as downtime or restart, which exhibit different behaviours compared to in-service period measurements, further reducing the quality of the monitoring data. In our research, the authors reached out to all paper mills and plants within the Mondi Group, to identify where the best data were available and collaborated with local expert to ensure the highest possible quality

of those before the start of the work. Due to commercial competition, the original dataset cannot be shared, but the publication should assist to find evidence that with the correct approach a predictive maintenance system can be incredibility successful. This dataset is composed of 51 different bearing, and for each the channels of acceleration, envelope and velocity were considered. Data were collected for 24 months, with 1h-sampled data, providing a total of more than 850.000 data-points to analyse.

4.2 Health Indicator construction The process of developing a Health Index (HI) holds a crucial role in the field of machinery prognostics. An appropriate HI can significantly enhance the accuracy of prognostic modelling, thereby improving the precision of the prediction results. Health indexes can be classified into two categories based on their construction methods: physical HIs and virtual HIs. Physical HIs are associated with the physics of failure and are typically derived from monitoring signals using statistical or signal processing techniques. In contrast, virtual HIs are often created by merging multiple physical HIs or multi-sensor signals, resulting in a loss of physical significance and offering only a virtual representation of the machinery's degradation trends [27]. RMS is the most commonly employed physical Health Index in the prediction of remaining useful life for machinery. [28] predicted the remaining useful life of bearings using RMS applied to vibration data. [29] extracted RMS and peak values from the wavelet coefficients as a means of predicting the remaining useful life of bearings. Similarly, approaches set out it [30] [31] also applied RMS to predict bearing anomalies in machineries. Some researchers constructed new physical Health Indexes based on statistical characteristics of signals in time domain. To evaluate the evolution of cracks in gear teeth, [32] quantified the proportion of a residual error signal that exceeded a baseline threshold. [33] developed a Physical Health Index for bearings by computing the energy ratio between residual signals obtained through autoregressive (AR) filtering and the original signals. On the side of virtual Health Index instead, the most popular technique is certainly PCA [14]. [34] used PCA to reduce the dimension of feature sets and further calculated the deviations between unknown states and the healthy state as a virtual Health Index. [35] used PCA combined with isometric feature mapping to construct a VHI for cutting tools. When dimensionality is a challenge however, [36] innovated with the usage of self-organizing map techniques, and since then this technique has been widely used in the VHI construction [37] [38] [26]. When faced with limited features, it is very popular in the literature [39] [40] [41] [42] to use a statistical, linear or non-linear, data transformation approach to create a virtual Health Index by combining multiple features. This latter has a clear advantage of understandability, which makes it more reliable to validate. Given the practical objective of the health index proposed in this paper, we chose to adopt the aforementioned method.

system where the unhealthy stage begins when the health-index exceeds a pre-specified alarm threshold based on historical initial points of defects for bearings. More complex methods for a threshold-defined two-stage division are found in the literature (Chebyshev inequality function [45], 3V Box-Cox transformation [46], Hotelling T2 statistic [47], locality preserving projection [48]) but complexity does not come at benefits of precision, as no method outperforms the others. When variations in fault patterns or operational conditions occur, the degradation trends of machinery may change, leading to an additional layer of complexity. In such cases, it becomes challenging to accurately describe the degradation processes using a signal degradation model. Consequently, it is necessary to further subdivide the unhealthy stage into different stages based on the various degradation trends. Some researchers have addressed this issue by dividing the degradation processes into multiple stages through the analysis of change points in health indexes or spectra [14]. The number of identified levels and the methods used for their identification vary and sophistication raises compared to the two-stage case. From using confidence levels to build a four-stage system [49], to analyse changes of frequency amplitudes in the power spectral density to develop a five-stage model [50], and apply classification or clustering algorithms, such as K-nearest neighbour [51], fuzzy cmeans [52] and K-means [53], to develop the multi-stage division of machinery, the available methodologies for researchers are numerous. For those industrial-oriented real applications though, semi-supervised learning has recently emerged as a prominent methodology [54] [55] [56], as in practical applications, obtaining accurate labels based on real-time bearing conditions can be far more challenging and semi-supervised approach allows for effective utilization of dataset when only a small subset of data have labels. In this paper, given the practical usage of the outcome, the latter approach is further developed and applied.

5. RESULTS The dataset used in this study consisted of the complete data records of approximately 50 bearings that were monitored over a period of 2 years across 3 distinct paper machines situated in the same mill. In order to establish the methodology, data from 23 bearings on a single machine were exclusively analysed. Subsequently, the developed methods were tested on the remaining machines to pp y ggeneralizability. y validate their applicability and

4.3 Health Stage division The concept of Health Stage division is akin to the commonly used terms "fault detection" or "fault diagnosis" in the field of prognostics and health management [43]. However, their objectives differ. Fault diagnosis aims to identify the specific fault patterns and severity of a given machine at a single point in time. In contrast, Health Stage division seeks to partition the ongoing degradation process of a machine into distinct Health Stages based on the fluctuating trends of health indicators [14] A simple but empirically-solid strategy for health stage division is presented by Wang [44], who developed a two-stage division

Figure 2 - Bearing vibration signal. (a) raw (b) (c) filtered To extract valuable insights from the vast amount of data in vibration-based Smart Maintenance, appropriate filtering techniques must be employed to mitigate the impact of noise on the analysis. Noise, which can arise from environmental factors or intentional sources, can interfere with the accuracy of the system,

necessitating its active management. A reliable method for noise reduction in the time domain is the application of Finite Impulse Response (FIR) moving average and standard deviation filters. These filters are not only simple and fast but also provide remarkable results by eliminating noise while retaining essential information and sharp step responses, as demonstrated in Figure 2

Figure 3 - Euclidean distance calculation (where p and q are two points) The process of developing a virtual health index commences with the calculation of the Euclidean distance between the signal's quiet value of each bearing and that of the signal at time t, as depicted in Figure 3, for each filtered component of the relative vibration channel signal. Multiple features become available for each time t, as shown in Figure 4. Following the methodology described in the

Figure 4 - Features for VHI developed by raw signal filter and Euclidean distance calculation Health Indicator construction chapter [39] [40] [41] [42], which incorporates the use of a non-linear minimum function, the data can be aggregated to create a virtual Health Index, as illustrated in Figure 5.

Figure 6 - Resulting threshold based on failure case. Red arrow = moment of bearing failure; yellow/orange arrow = signal pattern change. Yellow/Orange threshold defined as warning and alarm stage division. remarkable. In addition to the case used for generalization, three more bearing cases were available, and all were correctly identified by the developed methodology without any false positives or false negatives (see Figure 7). To ensure correct fitting, the method was also tested on the remaining two machines without recalibration.

Figure 7 - Prediction result on development paper machine The results, as depicted in Figure 8, were equally remarkable, with no false positives or false negatives identified, even in instances when no failure cases were observed on the machine.

Figure 5 - Virtual Health Index for a single bearing as derived by signal displayed in Figure 5 The final step involves dividing the Health Index into various health stages. As described in Chapter 4, a semi-supervised approach is implemented due to the scarcity of labelled data available in the dataset, which is limited by the practical run-tofailure cases, as discussed in section 4.1. The threshold for health stage division is determined based on the patterns observed in the failure case depicted in Figure 5, and explained in Figure 6. The availability of data from multiple paper machines allows for cross-validation to assess the extent to which the developed methodology can be generalized. The performance of the methodology on the machine used for method development was Figure 8 - Methodology testing on unseen/unbiased data

6. CONCLUSIONS AND FUTURE WORKS In this study, we have presented a methodology for implementing predictive maintenance utilizing a vast array of vibration data, despite limited availability of failure labels. Our approach was validated on multiple paper machines and demonstrated exceptional performance on various test and validation datasets. Unfortunately, due to commercial confidentiality, we are unable to disclose the original dataset. Nonetheless, our findings serve as a valuable contribution towards demonstrating the effectiveness of a well-designed predictive maintenance system.

7. ACKNOWLEDGMENTS This work was made possible thanks to the support of Mondi Group AG. A special thanks to the colleagues from the plants and the headquarter that committed their time and knowledge to the success of this work.

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PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY TE INTERNATIONAL®

Volume 9, Number 3, 2023

Granulated biomass fly ash coupled with fenton process for pulp and paper wastewater treatment JOÃO PERES RIBEIRO 1, NUNO C. CRUZ 1, MÁRCIA C. NEVES 2, SÓNIA M. RODRIGUES 1, LUÍS A.C. TARELHO 1 & MARIA ISABEL NUNES 1 The work describes the combination of granulated biomass fly ash (GBFA) with Fenton process to enhance the removal of adsorbable organic halides (AOX) from pulp bleaching wastewater. At optimal operating conditions, wastewater’s chemical and biochemical oxygen demand (COD and BOD5, respectively) and colour were also quantified, and operating cost of treatment assessed. For the first time, raw pulp bleaching wastewater was used to granulate BFA, instead of water, reducing the water footprint of the treatment. Five wastewater treatment setups were studied: (i) conventional Fenton process; (ii) GBFA application; (iii) simultaneous application of GBFA and Fenton process; (iv) sequential treatment by GBFA followed by Fenton process; (v) sequential treatment by Fenton process followed by GBFA. The latter yielded the highest AOX removal (60–70%), whilst COD was also reduced (≈15%) and wastewater biodegradability (BOD5/COD) was enhanced from 0.075 to a maximum of 0.134. Another positive feature of the proposed solution was that GBFA were successfully recovered and reused without regeneration, yielding similar AOX removal compared with fresh GBFA. The operating cost of removing 1 g of AOX from the pulp bleaching wastewater by the optimal treatment setup (60–70% removal of AOX) was 14–26% lower than the operating cost of conducting Fenton process alone (50% removal of AOX). Contact information: 1 CESAM – Centre for Environmental and Marine Studies, Department of Environment and Planning, University of Aveiro, 3810-193, Aveiro, Portugal 2 CICECO – Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal Environmental Pollution 317 (2023) 120777.

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PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY TE INTERNATIONAL®

Volume 9, Number 3, 2023

Synergies between Fibrillated Nanocellulose and Hot-Pressing of Papers Obtained from High-Yield Pulp CARLOS NEGRO 1, GUNILLA PETTERSSON 2, AMANDA MATTSSON 2, STAFFAN NYSTRÖM 2, JOSE LUIS SANCHEZ-SALVADOR 1 , ANGELES BLANCO 1 & PER ENGSTRAND 2 To extend the application of cost-effective high-yield pulps in packaging, strength and barrier properties are improved by advanced-strength additives or by hot-pressing. The aim of this study is to assess the synergic effects between the two approaches by using nanocellulose as a bulk additive, and by hot-pressing technology. Due to the synergic effect, dry strength increases by 118% while individual improvements are 31% by nanocellulose and 92% by hot-pressing. This effect is higher for mechanical fibrillated cellulose. After hot-pressing, all papers retain more than 22% of their dry strength. Hot-pressing greatly increases the paper’s ability to withstand compressive forces applied in short periods of time by 84%, with a further 30% increase due to the synergic effect of the fibrillated nanocellulose. Hot-pressing and the fibrillated cellulose greatly decrease air permeability (80% and 68%, respectively) for refining pretreated samples, due to the increased fiber flexibility, which increase up to 90% using the combined effect. The tear index increases with the addition of nanocellulose, but this effect is lost after hot-pressing. In general, fibrillation degree has a small effect which means that low-cost nanocellulose could be used in hot-pressed papers, providing products with a good strength and barrier capacity. Contact information: 1 Department of Chemical Engineering and Materials, University Complutense of Madrid, Avda Complutense s/n, 28040 Madrid, Spain; ablanco@ucm.es (A.B.) 2 Department of Engineering, Mathematics and Science Education (IMD), Mid Sweden University, SE-85170 Sundsvall, Sweden; amanda.mattsson@miun.se (A.M.); per.engstrand@miun.se (P.E.) Nanomaterials 2023, 13, 1931. https://doi.org/10.3390/nano13131931 Creative Commons Attribution 4.0 International License

Page 1 of 20

Article 6 – Pulping

nanomaterials Article

Synergies between Fibrillated Nanocellulose and Hot-Pressing of Papers Obtained from High-Yield Pulp Carlos Negro 1, * , Gunilla Pettersson 2 , Amanda Mattsson 2 , Staffan Nyström 2 , Jose Luis Sanchez-Salvador 1 , Angeles Blanco 1 and Per Engstrand 2 1

Department of Chemical Engineering and Materials, University Complutense of Madrid, Avda Complutense s/n, 28040 Madrid, Spain; ablanco@ucm.es (A.B.) Department of Engineering, Mathematics and Science Education (IMD), Mid Sweden University, SE-85170 Sundsvall, Sweden; amanda.mattsson@miun.se (A.M.); per.engstrand@miun.se (P.E.) Correspondence: cnegro@ucm.es; Tel.: +34-91-394-42-42

Abstract: To extend the application of cost-effective high-yield pulps in packaging, strength and barrier properties are improved by advanced-strength additives or by hot-pressing. The aim of this study is to assess the synergic effects between the two approaches by using nanocellulose as a bulk additive, and by hot-pressing technology. Due to the synergic effect, dry strength increases by 118% while individual improvements are 31% by nanocellulose and 92% by hot-pressing. This effect is higher for mechanical fibrillated cellulose. After hot-pressing, all papers retain more than 22% of their dry strength. Hot-pressing greatly increases the paper’s ability to withstand compressive forces applied in short periods of time by 84%, with a further 30% increase due to the synergic effect of the fibrillated nanocellulose. Hot-pressing and the fibrillated cellulose greatly decrease air permeability (80% and 68%, respectively) for refining pretreated samples, due to the increased fiber flexibility, which increase up to 90% using the combined effect. The tear index increases with the addition of nanocellulose, but this effect is lost after hot-pressing. In general, fibrillation degree has a small effect which means that low- cost nanocellulose could be used in hot-pressed papers, providing products with a good strength and barrier capacity. Citation: Negro, C.; Pettersson, G.; Mattsson, A.; Nyström, S.; Sanchez-Salvador, J.L.; Blanco, A.;

Keywords: hot-pressing technology; microcellulose; cellulose nanoﬁbers; nanocellulose; high-yield pulp; CTMP; paper quality; packaging

Engstrand, P. Synergies between Fibrillated Nanocellulose and Hot-Pressing of Papers Obtained from High-Yield Pulp. Nanomaterials 2023, 13, 1931. https://doi.org/ 10.3390/nano13131931 Academic Editor: Linda J. Johnston Received: 30 May 2023 Revised: 20 June 2023 Accepted: 23 June 2023 Published: 25 June 2023

1. Introduction High-yield pulps (HYP) have become a key material in sustainable products because of their resourcefulness and cost efficiency [1] and the potential to manufacture products which achieve certain important properties, such as a high bulk in paperboard and high light scattering in printing papers. They are produced at a yield of over 90% from different wood sources (or annual plants) by means of mechanical or combined chemical and mechanical processes [2,3]. One of the driving forces has been the fact that if high-yield processes can be used to a higher extent, it will be possible to manufacture more products from the same amount of wood since the corresponding yield for chemical pulps is around 50%. In addition, due to HYPs being a traditional and mature sector, industrial interest in this area is growing since new applications have been developed over the last few years. The market reduction, especially in printing products, due to digitalization, has forced the sector to search for other possible market strategies, transforming the processes and developing new HYP-based which includes their application for packaging to replace fossil-fuel-based plastic products [4]. Consequently, the research interest in improving the quality of papers obtained from HYPs has increased significantly in recent years [5,6]. The hot-pressing of various wood-based materials, such as wood, plywood, particle board, and fiberboard, has been used over the years to improve their material properties [7,8]. Song et al. (2018) showed that with a combination of chemical pre-treatment and

Nanomaterials 2023, 13, 1931. https://doi.org/10.3390/nano13131931

https://www.mdpi.com/journal/nanomaterials

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hot-pressing, it is possible to densify the wood by almost 300% up to 1300 kg/m3 and to improve the tensile strength by over 1000% to 587 MPa [9]. This was obtained when 12% of the lignin was left in the wood prior to hot-pressing, which was optimal to maximize both density and strength values. On the other hand, Cristescu et al. (2015) concluded that temperature (up to 250 ◦ C), compared to pressure and pressing time, is the most influential parameter in hot-pressing laminated beech, as it provides the highest density, strength, and lowest water sorption compared to the samples pressed at lower temperatures [10]. During hot-pressing, heat and mass-transfer processes interact with each other, in combination with deformation and chemical reactions, making the mechanism complex and challenging to investigate [11]. Therefore, simulations of hot-pressing have also been carried out to further understand the mechanisms at work [12,13]. Similar optimal amounts of lignin have been reported to maximize the reinforced effect of hot-pressed paper [14]. The benefit of using this hot-pressing method in combination with other methods to increase the strength of the sheet, such as the addition of chemicals, is that it is environmentally friendly and also that the sheet keeps its properties better over time [15]. In recent years, several studies have demonstrated that the hot-pressing of papers obtained with HYPs enhances their properties. Clear improvements are observed in both wet and dry tensile strength compared to non-pressed papers [16,17]. Joelsson et al. (2020) showed that the dry tensile strength of paper produced with various pulps, chemi-thermomechanical pulp (CTMP), thermomechanical pulp (TMP) and others, could be improved even by 100% when passing the paper through hot nips (200 ◦ C, 6 MPa) [18]. Moreover, the wet strength increased dramatically from 2 kN·m/kg to about 16 kN·m/kg after hot-pressing. A high compression strength was also achieved, probably due to the high bending stiffness of the lignin-rich CTMP fibers compared to lignin-free chemical pulp fibers. Furthermore, promising results have also been found regarding other important properties of the paper for the final applications, such as water resistance. Contact angle measurements showed increased values for the hot-pressed paper samples, which suggests a more hydrophobic surface due to the increased density and smoothness of the paper [18–20]. The quality profile of these laboratory paper sheets is in line with or superior to which is demanded today for commercial advanced sustainable packaging paper materials (even without any addition of chemicals, such as wet-strength agents), where very high strength is highly prioritized, in products such as liners, and paper bags. Moreover, it was lately shown that it is possible to achieve wet-strength levels of over 50% of the dry-strength level by combining the hot-pressing of CTMP or lignin-rich kraft pulp with sizing agents such as ASA [15]. Since the different levels of improvement were related to the lignin content [21], the prerequisite to achieve these improved properties, both for wood and paper materials, is that optimal conditions during the press-drying of sheets are achieved, specifically that the temperature exceeds the softening temperature of lignin and hemicellulose. In 2021, Joelsson indicated that even better strength improvements might be possible at further increased press-drying temperatures [22]. On the other hand, in recent decades, it has also been proved that nanocellulose (NC) significantly increases mechanical and barrier paper properties, allowing the use of paper in applications covered in our days by other materials. Numerous studies related to the production, characterization, and use of NC in different applications of interest are described in the literature [23–26]. This is due to the excellent properties of this family of products, including the ability to form stable three-dimensional networks, its great mechanical resistance, colloidal properties [27], its high specific surface, adsorption capacity [28] or the capacity of functionalization, among others [29,30]. All these properties together with the great availability, and biodegradable, biocompatible and environmentally friendly properties of these materials make them of great interest in an endless number of applications like biomedicine [26,31], nanocomposites [32], reinforced inorganic matrix [33], rheology

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modifiers [34], aerogels and foams [35], food industry [36], energy [37], environmental [38], papermaking [39] and many others [40,41]. One of the most promising NC applications is in papermaking, especially in bulk and surface applications [39]. NC has been applied in papermaking due to its strong properties, mainly its high strength and mechanical properties; dry and wet strength; Z-strength and fracture toughness [42,43]; decreased porosity and permeability; enhanced barrier properties towards air, grease, water vapor and liquids; high oxygen-barrier performance [44]; its low density, enabling grammage reduction while increasing tensile strength [45]; increased filler retention and reduced surface roughness and water penetration [46]; decreased linting problems in printing papers [47]; and increased coloring efficiency of colored papers [48], water treatments [49], etc. Furthermore, as NC has a relatively high number of carboxyl groups, their reactivity make it possible to modify the hydrophilicity and charge surface to improve their potential applications in papermaking [39,50,51]. In addition, among all potential applications in papermaking, the use of NC as a reinforcement additive has been the most studied. NC-reinforced paper has the potential not only to improve conventional packaging paper, but also to progress to the substitution of non-biodegradable plastics obtained from fossil resources, as in the case of food packaging. All published market studies about NC show that the market is expected to grow from USD 300 million currently to USD 800 million by 2026, which means an annual growth rate of more than 30% in the coming years, and this will certainly continue to grow in the future driven by the sustainability trend [52]. Therefore, the industrial and academic community are making a tremendous effort to unlock the potential for engineered sustainable materials based on NC, but several challenges remain related to the production, characterization and application of these products [53,54]. Factors such as process optimization and cost-effective production methods need to be further addressed. In this aspect, the in situ production and application of NC is considered. From this point of view, NC produced from fibers containing lignin, called lignocellulosic micro/nanofibers [55–58], and from recycled fibers, is attracting more attention since paper improvements were observed in z-strength, tensile index, tear index, burst index, E-modulus, strain at break, tensile stiffness, and air resistance [59,60]. The aim of this manuscript is to investigate the synergic effect of using fibrillated cellulose, containing micro and nanofibers (CMNFs), as a bulk additive, and hot-pressing to improve the properties of the paper. The cellulose source to produce CMNFs was the waste from a liner paper machine using 100% recovered paper. To our best knowledge, the use of NC to further enhance paper properties in conjunction to hot-pressing is a novel approach that has not been reported in the literature yet. 2. Materials and Methods 2.1. Materials Waste liner from a paper machine using 100% recycled paper was used as cellulose raw material to produce CMNFs. The reagents used for the TEMPO-mediated oxidation pretreatment were 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) reagent (98 wt.%) supplied by Sigma-Aldrich (St. Louis, MO, USA), as well as NaBr (>98.5 wt.%), NaOH (>98 wt.%) and NaClO (12% w/v, previously titrated to obtain the actual concentration) which were supplied by Panreac AppliChem (Barcelona, Spain). Other reagents used for the characterization of CMNFs were NaCl (>99.5 wt.%), NaOH (>98 wt.%), H2 SO4 at 98 wt.% and crystal violet (>90.0 wt.% anhydrous basis) supplied by Merck (Madrid, Spain), and 0.1 wt.% Poly-L-Lysine solution with a molecular weight > 70,000 by Electron Microscopy Sciences (Hatfield, PA, USA). For HYP production, a standard bleached flash dried spruce CTMP (CSF 420 mL) from SCA Östrand mill (Timrå, Sweden) was used to prepare the paper hand sheets.

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2.2. Methods 2.2.1. Cellulose Pretreatments To produce the CMNFs, first, liner was left to soak for 24 h to favor fiber swelling before disintegration into a pulp disintegrator (PTI, Vorchdorf, Austria) at 30,000 revolutions. Two pretreatments were used to obtain the CMNFs. On the one hand, refining was used as the mechanical pretreatment using a PFI mill manufactured by Hamjem Maskin AS (Hamar, Norway). The pulp consistency was adjusted to 10 wt.% and the pulp was subjected to 20,000 revolutions [61,62]. On the other hand, a TEMPO-mediated oxidation (5T-Oxidation) chemical pretreatment was performed in a 5 L glass reactor at 1 wt.% cellulose consistency with 0.1 mmol TEMPO/g pulp and 1 mmol NaBr/g pulp [63,64]. Then, 5 mmol NaClO/g pulp was added to start the reaction which was conducted at room temperature and with stirring conditions at 200 rpm. During the process, pH was controlled to 10, adding a 2 M NaOH solution dropwise until pH remained constant [65,66]. 2.2.2. Cellulose Treatment To produce CMNFs, pretreated pulps were mechanically fibrillated using a highpressure laboratory homogenizer PANDA 2000 PLUS (GEA Niro Soavy, Parma, Italy) using pulp suspensions with a consistency around 1 wt.%. Figure 1 shows a scheme of the production of the CMNFs from the raw material. To achieve different nanofibrillation yields, four pressure sequences (PS) were carried out in the high-pressure homogenization (HPH). The PSs are described below from less intensive to more intensive:

• • • •

PS0: No homogenization of the ﬁbers, only the pretreated samples. PS1: 3 passes of HPH at 300 bars. PS2: 3 passes of HPH at 300 bars and 3 additional passes at 600 bars. PS3: 3 passes of HPH at 300 bars, 3 passes at 600 bars and 3 passes at 900 bars.

Figure 1. Scheme of CMNF production.

2.2.3. Chemical Characterization of the Raw Material Used to Produce CMNFs First, the broke liner was dried to obtain the total solid content of the sample. Extractives, insoluble and soluble lignin, pectin, cellulose, hemicellulose, and ashes were measured by triplicate. Extractives of the sample were determined by Soxhlet extraction

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according to TAPPI T204 [67] whereas the ash content was determined by calcination at 525 ◦ C, according to TAPPI T211 [68]. Soluble and insoluble lignin, pectin, cellulose and hemicellulose of raw materials were obtained following the NREL/TP-510-42618 standard [69]. A weight of 300 mg of the material was hydrolyzed with 3 mL of 72 wt.% H2 SO4 for 1 h in a water bath at 30 ◦ C. Then, 84 g of deionized water was added and introduced in an autoclave at 121 ◦ C for 1 h. The hydrolyzed samples were vacuum-filtered. Insoluble lignin remained in the filter whereas the soluble lignin fraction was obtained by measuring the absorbance of the filtrate in the UV-Visible spectrophotometer at 240 nm. Hemicellulose, cellulose and pectin content were analyzed in the filtrate after neutralization with CaCO3 and passed through a 0.2 μm filter by using a modular HPLC device Jasco series 2000 (Jasco, Tokyo, Japan) [70]. 2.2.4. Characterization of CMNFs The aspect ratio was obtained by the simplified gel point (GP) methodology based on the sedimentation of the fibers by using increments of the derivative at the origin of the curve Co vs. Hs/Ho, as Equation (1) shows [71]. To determine the GP value, a 250 mL CMNF suspension was prepared using deionized water and 200 μL of crystal violet 0.1 wt.% to favor the sediment visualization [72]. The aspect ratio was calculated with Equation (2) according to Varanasi et al. (2013) [73], assuming a density of fibers around 1500 kg/m3 and the crowding number theory described by Martinez et al. (2001) [74]: ∅ o ( i ) − ∅ o (0) ∅o (i ) d∅o GP = lim ≈ (1) = Hs /Ho →0 d( Hs/Ho ) ( Hs/Ho (i )) − ( Hs/Ho (0)) ( Hs/Ho(i )) Aspect ratio = 6.0·

1000 kg GP m3

(2)

To characterize the morphology of CMNFs, optical microscopy (OM) and transmission electron microscopy (TEM) were used. Micro- and nanofibrils were visualized under 5× magnification using a Zeiss Axio Lab.A1 optical microscope and a color microscope camera Zeiss AxioCam eRc 5s (Carl Zeiss Microscopy GmbH, Göttingen, Germany). TEM analyses were carried out at the Centro Nacional de Microscopía Electrónica (Madrid, Spain) with a JEM 1400 microscope from JEOL (Tokyo, Japan). Samples were prepared adding 15 μL of 10% Poly-L-Lysine solution on a copper grid covered with a Formvar/carbon continuous layer. Then, 12 μL of 0.005 wt.% of CMNF suspensions were deposited and left to dry before TEM analysis [75]. To process the images, the program of public domain Image J was used to measure the diameter range of the different suspensions and evaluate the heterogeneity of the CMNFs. Transmittance readings of 0.1 wt.% diluted suspensions were measured in the wavelength of 600 nm on a UV–Vis Shimadzu spectrophotometer UV-160A using distilled water as reference. Finally, the carboxyl content of the suspensions was determined by conductometric titration according to Xu et al. (2022) [76]. 2.2.5. Hand Sheet Preparation and Testing The CTMP pulp was soaked in hot water for around 1 h to soften the fibers (and favor fiber swelling). Then, they were hot disintegrated at 2% in solids using a PTI pulp disintegrator (Vorchdorf, Austria) at 30,000 revolutions according to ISO 5263-3 [77]. Hand sheets of 100 g/m2 were prepared using a Rapid Köthen sheet former (Paper Testing Instruments, Pettenbach, Austria) according to ISO 5269-2 [78]. The sheets were dried in the drying plates in the Rapid Köthen until they reached a dry content of 65–70%, and thereafter put in a sealed plastic bag to maintain their moisture level. They were kept at 4 ◦ C until hot-pressing. Figure 2 shows a scheme of the process of hand sheet production.

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Figure 2. Scheme of hand sheet production.

All sheets were characterized according to the different ISO standards after conditioning according to ISO 187 [79]. Density (kg/m3 ) was determined following ISO 534, grammage (g/m2 ) using ISO 536, and thickness (μm) with ISO 534 [80,81]. The determination of air permeability (mL/min) was measured according to the Bendtsen method following the ISO 5636 [82]. Tensile index (kN·m/kg) was conducted according to ISO 1924 and the wet tensile index (kN·m/kg) following the ISO 3781 [83,84]. Tear resistance (mN) was determined according to ISO 1974 and SCT (short-span compression test) (kN·m/kg) following ISO 9895 [85,86]. Error bars were calculated using the standard deviation between samples with the same conditions. Paper samples were analyzed using a high-resolution SEM (Tescan Maya3-2016, TESCAN Brno, s.r.o., Brno, Czechia). All samples were prepared by sputtering them with a 5 nm thin layer of iridium prior to imaging. The applied electron beam voltage was 3.00 kV, and the beam intensity was 1.00. To obtain images of the structures at different scales, magnifications 200×, 1000×, and 2000× were used. The working distance to the sample was set to approximately 8 mm. 2.2.6. Hot-Pressing Technology The paper sheets were hot-pressed in a planar pressing equipment built at Mid Sweden University. This equipment mainly contains three parts: the heating blocks, pillar stand, and compression testing machine (see Figure 3). The heating blocks have a dimension of 300 × 300 × 40 mm and have three pockets in which flat electrical heating elements, each of 500 W, are inserted. Due to the thickness of 30 mm steel between elements and the pressing surface, variations in the temperature distribution will be at a minimum. The heating blocks are, via 20 mm thermal isolating plates, mounted in pillar rack ball brushings to ensure the best alignment between the blocks. In turn, the upper pillar rack is fixed to a hydraulic MTSTM material testing machine loadcell and the lower part to the movable hydraulic piston rod. For the control of block temperature, each has a built-in thermocouple sensor connected to Eurotherm PID-type regulators which are limited to 300 ◦ C. For the control of compression loads, MTSTM RPC software is used for creating block-programmed load vs. time sequences up to 100 kN. In these experiments, the pressing time was set to 3 s, and the pressure to 3.5 mPa. All experiments were carried out at 260 ◦ C with a dry content of 65–70% on the sheets. The sheets were manually handled during the hot-pressing trials.

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Figure 3. Planar hot-pressing unit with temperature and load controlled pressing plates built into an MTS equipment (developed) at Mid Sweden University.

3. Results and Discussion 3.1. Characterization of the Cellulosic Raw Material and the CMNF Suspensions Chemical characterization of the spruce CTMP used as the HYP and the broke liner used to produce the CMNFs is shown in Table 1, together with the composition of the oxidized pulp after 5T-Oxidation. Pulp after refining was not characterized due to the pretreatment only being mechanical. The raw materials (spruce and liner) were dried to obtain a total solid content amounting to 96.6 ± 0.2% and 96.8 ± 0.2% for liner and spruce, respectively. The ash content due to the presence of fillers in the recycled paper was elevated with an average value of 14.2%, whereas in the spruce this value was under 1% [87]. On the other hand, the content of total lignin in both raw materials was also elevated with an average value of 17.2% and 29.9%, indicating that only part of the initial lignin was removed to facilitate the separation of the virgin fibers, as usually performed in packaging paper. The cellulose content was similar in both cases with a 55.2 ± 0.9% in the liner and 48.8 ± 1.2% for the spruce CTMP. The hemicellulose content, formed in the chemical composition by arabinose and the overlapping of xylose, mannose, and galactose, was 10.6% in liner while the spruce almost doubled this value with 18.5%. Finally, the extractive content was under 2% for the liner and around 0.5% for the spruce whereas the pectin content was also low, around 1.5% in both cases. This last parameter was calculated as the galacturonic acid content in the hydrolyzed sample, but also the rhamnose, which majoritively proceeds from pectin, although to a lesser extent from hemicellulose. However, the content of rhamnose is insignificant in the sample under 0.4%, assuming all rhamnose came from the pectin [88]. Table 1. Chemical composition of spruce CTMP as HYP and recycled liner for CMNF production before and after 5T-oxidation. Chemical Composition (Dry Basis)

Spruce CTMP

Liner

Liner after 5T-Oxidation

Ash (%) Cellulose (%) Hemicellulose (%) Acid insoluble lignin (%) Acid soluble lignin (%) Pectin (%) Extractives (%)

0.7 ± 0.2 48.8 ± 1.2 18.5 ± 0.9 25.6 ± 0.4 4.3 ± 0.1 1.6 ± 0.3 0.5 ± 0.1

14.2 ± 0.1 55.2 ± 0.9 10.6 ± 0.6 11.7 ± 0.4 5.5 ± 0.1 1.2 ± 0.3 1.7 ± 0.3

16.0 ± 0.5 52.7 ± 1.5 13.1 ± 0.4 7.1 ± 0.5 9.0 ± 1.5 <0.5 1.9 ± 0.2

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The suspensions obtained after the different pretreatments and the mechanical homogenization at several intensities were characterized. The samples pretreated by refining have an proportion of solids of around 1–1.1% in the suspensions and the carboxyl group content was 0.46 ± 0.03 mmol/g pulp. In the case of pulps pretreated by TEMPO-mediated oxidation, the solid content was 1.1–1.2% and the carboxyl group content increased up to 1.16 ± 0.04 mmol/g pulp which suggested good fiber oxidation, with a remarkable increase similar to other studies [63,65,76]. The pulp had a higher content of ashes due to the production of salts as a parallel reaction during the oxidation [89]. In addition, the action of the oxidant removes part of the insoluble lignin and dissolves the cellulose at a higher proportion than the hemicellulose [64,90]. On the other hand, in neither of the pretreatments was a variation in the carboxyl groups observed with the intensity of the homogenization. Table 2 shows the transmittance and aspect ratio of the obtained CMNF suspensions. Transmittance gives an idea of the homogeneity of the CMNFs fibers. When a sample has been highly fibrillated, the minimum possible diameter is reached, and the suspension becomes optically transparent at a test concentration (0.1 wt.%), with a transmittance near to 100% [91,92]. Aspect ratio refers to the relationship between the length and the width of the fibers. It is a fundamental parameter used to describe the morphology and physical properties of CMNFs, providing valuable information that influence their mechanical, thermal, and optical properties [72,93]. Samples obtained by a refining pretreatment have a low transmittance associated with a low light pass and the presence of more microfibrils than nanofibrils. In the case of chemically pretreated samples, the proportion of nanofibrils is higher and the value increases with the intensity of homogenization. It is interesting to point out that the pretreated sample with 5T-oxidation without homogenization (PS0), shows too high a transmittance value due to the sedimentation of the fibers, since the cellulose has not been subjected to any type of defibrillation. As expected, results of the aspect ratio show an increase with the intensity of homogenization. Comparing both pretreatments, it is observed that in the case of refining, the fibers are separated from the primary structure producing more ramified fibers which increase the aspect ratio values. In the case of 5T-Oxidation, besides cellulose oxidation, the oxidant also produces the breakage of the cellulose chains into smaller units as reflected in lower aspect ratios [72]. Table 2. Transmittance and aspect ratio of CMNF suspensions. Transmittance

Aspect Ratio

Homogenization Intensities

Reﬁning

5T-Oxidation

Reﬁning

5T-Oxidation

PS0 PS1 PS2 PS3

4.5 ± 0.3 4.6 ± 0.4 5.5 ± 0.3 9.5 ± 0.5

39.1 ± 2.2 22.9 ± 0.1 27.6 ± 0.6 40.7 ± 0.2

86 ± 5 127 ± 5 127 ± 6 128 ± 5

43 ± 2 76 ± 3 101 ± 7 103 ± 8

Micrographs of the suspensions have been carried out using OM (Figure 4) and TEM (Figure 5) at 5× and 1000× magnification, respectively. At least five images of each microscopic technique were taken. In addition, the variety of magnifications allows us to also evaluate the degree of homogeneity of the fiber size. The microfibrils after the refining pretreatment (PS0) showed a diameter range from 3 to 40 μm as observed in the OM micrographs. However, TEM images show some thinner fibers of 100 nm but in a very small proportion. Only after six homogenization passes (PS2) was is possible to observe a representative number of nanofibers in the samples. After the most intensive mechanical treatment (PS3), the diameter range of the sample was reduced to a range between 20 nm and 6 μm. In the case of the fibers treated with TEMPO-mediated oxidation, the diameter range without homogenization was more heterogeneous with micro and nanofibrils from 30 nm to 60 μm. Only after the sample was subjected to the mechanical treatment (PS1) did cellulose start to fibrillate in a notable way, being mostly nanofibers.

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After nine homogenization passes these CMNFs were more homogeneous with a diameter range between 15 and 70 nm.

Figure 4. Optical micrographs (OM) at 5× magniﬁcation of the CMNF suspensions.

Figure 5. TEM micrographs at 1000× magniﬁcation of the CMNF suspensions.

3.2. Paper Properties 3.2.1. Air Permeability The main property affected by the presence of NC was the reduction in air permeability, providing products with a good barrier capacity that is beneficial for applications in the packaging industry, especially for food packaging [94]. As it can be seen in Figure 6, in which CMNFs produced with PS2 homogenization sequence are used, the increase in fibrillated cellulose dosage significantly decreases air permeability by up to 68%, from 2.084 ± 75 mL/min to 670 ± 52 mL/min, with the addition of 4.5% of refined CMNFs in non-hot-pressed papers (NHP). The synergy effect on air permeability further increases after hot-pressing (HP) up to 50%, from 418 ± 32 mL/min to 211 ± 30 mL/min. This can be explained because at high temperatures, the fiber structure

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becomes more ﬂexible and easier to compress, reaching a high sheet density, and this effect is accentuated with the presence of CMNFs. NC also acts by blocking the voids in the 3D network, reducing the ease of air-volume passage within, since compacted NC provides longer tracks for air molecules to pass through [95]. Air-permeability reduction is also related to a decrease in porosity with NC addition [96].

Figure 6. Inﬂuence of CMNF dosages on air permeability.

It is remarkable that it is possible to achieve a significant air permeability reduction at very-low-refining NC dosages (1.5%), decreasing by 40% and 32% in the NHP and HP papers, respectively. This suggests that a low NC dosage is enough to achieve the desired properties. It was also observed that the best results were obtained using a refining process during the pretreatment to produce CMNFs instead of a tempo-mediated oxidation process (TMO); this can be explained by the fact that with the refining process more flexible fibers with a higher fine content were obtained, leading to an easier network structure to compress. At this low NC dosage (1.5%), a series of tests were performed to calculate the influence of the fibrillation degree on the reduction in air permeability using the fibrillated cellulose obtained using the refining pretreatment. Figure 7 shows that air permeability slightly decreases when the fibrillation degree increases but the improvement does not justify the use of highly fibrillated NC such as TMO. This is important because low-cost fibrillated NC could be used in hot-pressed papers. On the other hand, by increasing refining, it is possible to obtain denser products; this is due to the improvement in fiber flexibility and the higher content of fines.

Figure 7. Inﬂuence of CMNFs on air permeability at dosage 1.5%.

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The high differences between the hot-pressed and non-hot-pressed samples could be explained because of the collapse of the fiber network causing a higher density. In fact, the density of the hot-pressed papers reaches values around 800 kg/m3 , almost double the average density of the non-hot-pressed papers 450 kg/m3 . However, this is not the only factor as no differences were obtained in the densities of the non-hot-pressed sheet independently of the NC dosage or of the fibrillation degree. The reduction of bulk with NC addition can be also associated with intrinsic NC properties, the better fiber network accommodation entails more compacted papers [97]. The synergy between the use of fibrillated cellulose as a bulk additive and hot-pressing is very significant. Hot-pressing and fibrillated cellulose highly decrease the air permeability (80% and up to 68%, respectively) for refining the pretreated samples, due to the increased fiber flexibility, which increase up to 90% using the combined effect. Figure 8 shows SEM images of different samples; as it can be observed, the surface of the samples containing CMNFs is covered by the fibrillated cellulose reducing and closing the voids formed in the 3D fiber network by the larger fibers and, as consequence, these papers have a lower air permeability. 3.2.2. Dry Strength Figure 9 shows the increase in tensile index (tensile strength divided by the grammage of the sheet) when increasing the dosage of fibrillated cellulose produced with a PS2 homogenization sequence. The fiber network strength increased by increasing the number of bonds. The tensile index increased from 28.3 ± 1.2 kN·m/kg to 37.2 ± 1.0 kN·m/kg (31.4%) in non-hot-pressed papers and from 54.6 ± 2.7 kN·m/kg to 61.9 ± 1.8 kN·m/kg (13.4%) in hot-pressed papers when adding refining CMNFs. Due to their high aspect ratio and large relative surface area, CMNFs can enhance the bonding between fibers and even form a more crosslinked network [98]. The synergy between the use of fibrillated cellulose as a bulk additive and hot-pressing is very significant. In the case of dry strength, improvements up to 118% are obtained while individual improvements are up to 31% by CMNFs and 92% by hot-pressing (see Figure 9). It should be noted that the addition of fibrillated cellulose also increases the tensile index after hot-pressing but to a lower level. However, this increment is small in comparison to the effect of the hot-press itself, which almost doubles the tensile index. This effect is associated in part to the presence of lignin in the HYP [18]. Therefore, the fiber bonds are not the only responsible aspect of this increase after hot-pressing, supporting the theory that paper is strengthened by new covalent bonds, possibly in a crosslinking structure within the lignin and/or between the lignin and carbohydrates. This can also be demonstrated when applying 1.5% of refining CMNFs at different fibrillation degrees as it is shown in Figure 10. As expected, compression strength (SCT) followed the same pattern as tensile index as shows in Figure 11. 3.2.3. Wet Strength It is well known that independently of the type of pulp used to produce the paper, the inter-fiber bonding is unstable in water in untreated papers. As fibrillated cellulose has a high capacity to absorb water, normally the wet strength of paper containing NC decreases except in the cases in which the fibrillated material is treated to become hydrophobic.

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Figure 8. SEM images of different papers.

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Figure 9. Inﬂuence of ﬁbrillated nanocellulose on tensile index.

Figure 10. Influence of 1.5% of fibrillated cellulose on tensile index at different fibrillation degrees.

Figure 11. Inﬂuence of CMNFs on SCT.

As expected, results show that without hot-pressing, papers do not have wet strength. However, after application of hot-pressing technology, all papers, independently of the dosage and type of ﬁbrillated cellulose, retain more than 20% of their wet tensile strength (See Figure 12). A paper is considered to have good wet strength properties when it retains more than the 15% of its dry tensile strength after being immersed in water [99]. The lower water uptake can be explained by a combination of factors: 1.

The presence of fibrillated cellulose reduces the voids between fibers in the sheet becoming smaller or closed, providing more fiber-network bonding capacity [100]. The lignin content of CTMP could act acting to protect these fiber-fiber bonds at a high temperature.

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2. 3.

Due to a more hydrophobic surface character of the paper after hot-pressing technology [101]. New water-resistant bonds such as covalent bonds are formed during hot-pressing [102].

Figure 12. Inﬂuence of ﬁbrillated cellulose on wet strength after hot-pressing technology.

Furthermore, CMNFs can retain more water using hydrogen bonding and within the 3D network than pulp fibers due to their large specific area and the high number of carboxyl groups they contain. Consequently, its addition can improve the hydrogen bonds between the cellulose fibers during the pressing process, thus increasing the web strength. 3.2.4. Tear Resistance One of the drawbacks of hot-pressing technology is that the tear index decreases because the paper obtained has a higher density and it is more rigid. It was decided to test if the addition of fibrillation material could avoid at least partially this loss in tear index. As can be seen in Figure 13, tear index increases with the addition of CMNFs maintaining the fibrillation degree in PS2 and further increases with the fibrillation degree maintaining the CMNF dose at 1.5% (Figure 13). Further improvements were achieved than previous studies by Guan et al. (2019) and Balea et al. (2019) demonstrated, which reported that NC content did cause a slight increase in the tear index [59,103]; however, this effect was lost after hot-pressing as the material was still very rigid, limiting the application of hot-press papers to those applications in which tear index values are not critical.

Figure 13. Inﬂuence of CMNFs on tear resistance.

4. Conclusions The synergy between the use of fibrillated cellulose as a bulk additive and hot-pressing has been assessed. This synergy effect is very significant, further improving the properties of hot-pressed papers. Hot-pressing and fibrillated cellulose highly decrease air permeability (by 80% and 68%, respectively) for refining pretreated samples, due to the increased fiber flexibility, which increases up to 90% due to the combined effects. In the case of dry strength, improvements up to 118% can be obtained while individual improvements were 31% by

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CMNF and 92% by hot-pressing. This effect is more pronounced for mechanical fibrillated cellulose. It is important to note that after hot-pressing, all papers retain a wet strength 22% higher than that of the dry strength, even at high NC dosages. Furthermore, the combined effect also increases the SCT values, related to paper’s ability to withstand compressive forces applied in a short period of time, by 110% while hot-pressing produces an increase of 84% compared to the reference paper. The tear index increases with the addition of nanocellulose, but this effect is lost after hot-pressing. In general, the fibrillation degree has a low effect, which means that low-cost nanocellulose could be used in hot-pressed papers to provide products with a good strength and barrier capacity. Data show that it is possible to extend the application of cost-effective high-yield-pulp packaging through improving strength and barrier properties by using CMNF as a bulk additive and by hot-pressing the obtained papers. This shows that in hot-pressing technology, fiber bonding plays a key role, as well as the new covalent bonds formed at high temperature, possibly in a crosslinking structure within the lignin and/or between the lignin and carbohydrates. As lignin could play an important role in the enhanced properties of hot-pressed paper, it is recommended to explore the possibility of using lignin-based nanoparticles to obtain more knowledge on this theory. Author Contributions: Conceptualization, C.N. and P.E.; methodology, A.B., C.N., A.M. and G.P.; validation, C.N. and P.E.; formal analysis, A.M., G.P., A.B. and C.N.; investigation, A.M., G.P., A.B., J.L.S.-S., S.N. and C.N.; resources, P.E. and C.N.; data curation, C.N., A.M., A.B. and C.N.; writing— original draft preparation, A.M., G.P., A.B., J.L.S.-S. and C.N.; writing—review and editing, A.M., G.P., A.B., J.L.S.-S. and C.N.; visualization, A.M., G.P., A.B., J.L.S.-S., C.N. and P.E.; supervision, P.E.; project administration, C.N. and P.E.; funding acquisition, C.N. and P.E. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by the mobility grant received from the Spanish Minister of Universities, ref: PRX21/00600. We also want to acknowledge the funding of the project nr. 20180234 by the Swedish Foundation: Familjen Kamprads Stiftelse. Data Availability Statement: Data available on request. Acknowledgments: The authors want to express their gratitude to SCA R&D Center (Sundsvall) for allowing the use of its facilities for hand sheet preparation and its characterization. Conflicts of Interest: The authors declare no conflict of interest.

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PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY T INTERNATIONAL®

Volume 9, Number 3, 2023

A life cycle and product type based estimator for quantifying the carbon stored in wood products XINYUAN WEI 1,2, JIANHENG ZHAO 2,3, DANIEL J. HAYES 3, ADAM DAIGNEAULT 3 & HE ZHU 4 Background Timber harvesting and industrial wood processing laterally transfer the carbon stored in forest sectors to wood products creating a wood products carbon pool. The carbon stored in wood products is allocated to end-use wood products (e.g., paper, furniture), landfill, and charcoal. Wood products can store substantial amounts of carbon and contribute to the mitigation of greenhouse effects. Therefore, accurate accounts for the size of wood products carbon pools for different regions are essential to estimating the landatmosphere carbon exchange by using the bottom-up approach of carbon stock change. Results To quantify the carbon stored in wood products, we developed a state-of-the-art estimator (Wood Products Carbon Storage Estimator, WPsCS Estimator) that includes the wood products disposal, recycling, and waste wood decomposition processes. The wood products carbon pool in this estimator has three subpools: (1) end-use wood products, (2) landfill, and (3) charcoal carbon. In addition, it has a user-friendly interface, which can be used to easily parameterize and calibrate an estimation. To evaluate its performance, we applied this estimator to account for the carbon stored in wood products made from the timber harvested in Maine, USA, and the carbon storage of wood products consumed in the United States. Conclusion The WPsCS Estimator can efficiently and easily quantify the carbon stored in harvested wood products for a given region over a specific period, which was demonstrated with two illustrative examples. In addition, WPsCS Estimator has a user-friendly interface, and all parameters can be easily modified. Contact information: 1 Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA. 2 Center for Research on Sustainable Forests, University of Maine, Orono, ME 04469, USA. 3 School of Forest Resources, University of Maine, Orono, ME 04469, USA. 4 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. Carbon Balance and Management (2023) 18:1 https://doi.org/10.1186/s13021-022-00220-y Creative Commons Attribution 4.0 International License

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Article 7 – LCA of Wood Products

Wei et al. Carbon Balance and Management (2023) 18:1 https://doi.org/10.1186/s13021-022-00220-y

Carbon Balance and Management

Open Access

METHODOLOGY

A life cycle and product type based estimator for quantifying the carbon stored in wood products Xinyuan Wei1,2* , Jianheng Zhao2,3, Daniel J. Hayes3, Adam Daigneault3 and He Zhu4

Abstract Background Timber harvesting and industrial wood processing laterally transfer the carbon stored in forest sectors to wood products creating a wood products carbon pool. The carbon stored in wood products is allocated to end-use wood products (e.g., paper, furniture), landfill, and charcoal. Wood products can store substantial amounts of carbon and contribute to the mitigation of greenhouse effects. Therefore, accurate accounts for the size of wood products carbon pools for different regions are essential to estimating the land-atmosphere carbon exchange by using the bottom-up approach of carbon stock change. Results To quantify the carbon stored in wood products, we developed a state-of-the-art estimator (Wood Products Carbon Storage Estimator, WPsCS Estimator) that includes the wood products disposal, recycling, and waste wood decomposition processes. The wood products carbon pool in this estimator has three subpools: (1) end-use wood products, (2) landfill, and (3) charcoal carbon. In addition, it has a user-friendly interface, which can be used to easily parameterize and calibrate an estimation. To evaluate its performance, we applied this estimator to account for the carbon stored in wood products made from the timber harvested in Maine, USA, and the carbon storage of wood products consumed in the United States. Conclusion The WPsCS Estimator can efficiently and easily quantify the carbon stored in harvested wood products for a given region over a specific period, which was demonstrated with two illustrative examples. In addition, WPsCS Estimator has a user-friendly interface, and all parameters can be easily modified. Keywords Carbon pool, Carbon storage, Estimator, Life cycle, Recycle, Wood products

*Correspondence: Xinyuan Wei xwei4@buﬀalo.edu 1 Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA 2 Center for Research on Sustainable Forests, University of Maine, Orono, ME 04469, USA 3 School of Forest Resources, University of Maine, Orono, ME 04469, USA 4 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China

Background Accounting for the carbon stored in harvested wood products is necessary to analyze the full function of forest ecosystems in sequestering atmospheric carbon and mitigating the greenhouse effect [1, 2]. In general, the carbon budget of end-use wood products pools is calculated as the difference between inputs from harvest and losses to decay or trade over a given period. Where inputs exceed losses over this period, carbon accumulates in wood products pools and represents a net sink of atmospheric carbon. Johnston and Radeloff [3] found that the carbon sequestered in end-use wood products served as a net sink of 90 Tg C globally in 2015. Zhang et al. [4] reported

© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativeco mmons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

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a larger carbon sink in global end-use wood products, with an average of 122 Tg C per year during the period of 1992–2015. This annual sink of harvested carbon is heavily influenced by demand and supply in the products market, which is impacted by various social-economic factors such as population and household income, technological advancement in the wood industry, climate and other environmental factors, and forest management strategies [5–8]. Therefore, an accurate accounting for the carbon stored in wood products is essential to assessing land-atmosphere carbon exchange by developing carbon budgets at regional, continental, and global scales. The Intergovernmental Panel on Climate Change (IPCC) provides calculation guidance for estimating the size of harvested wood products carbon pools and their annual stock changes in three tiers of approach that can be used based on the availability of wood products data and the level of aggregation in the pool category definitions [9]. This guidance has been widely used to develop a considerable number of harvested wood products carbon accounting models and frameworks, which have been widely applied to various system boundaries [e.g., 101112]. Brunet-Navarro et al. [13] reviewed 41 wood product carbon accounting models and summarized their characteristics. These models are different in their system boundary, spin-up, bucking allocation method, number of carbon pools, treatment of wood product disposal and recycling processes, as well as technological advancement in the wood industry. The 2006 IPCC guidelines describe four approaches to define system boundaries for wood products carbon storage estimation [13, 14]. The stock-change approach estimates the carbon in wood products consumed and physically stored in the study area. The atmospheric flow approach estimates the carbon stored in wood products made from the harvested timber from local forests along with the emissions from wood products consumed in the study area, but the carbon emissions from the products exported to and consumed in other regions are not counted. The production approach estimates the carbon stored in wood products made from timber harvested in the study area. The carbon stock and emission from exported products are counted, but the carbon stock in imported wood products is not included in the calculation. Finally, the simple decay approach estimates carbon stored in wood products consumed in the study area. Meanwhile, the carbon stock and emission made from local forests but exported and consumed in other regions are also counted in this approach. Wood products estimation models often use a “spinup” process to account for the initial size of the carbon pool at the start of the period for reporting. The initialization is not always included in the accounting [e.g., 15],

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but the study or reporting time period should be well documented. Another strategy is to run the spin-up for a long enough period using historical wood production data to reach the equilibrium stage [16]. If the harvested timber is not adequately categorized into intermediate and end-use wood products, a bucking allocation process is required, which refers to the allocation of harvested timber to different wood products pools [17]. A carbon pool is typically defined as a group of wood products that have a similar life cycle [18]. Wood product disposal is the time point when products are retired from use and disposed [13]. The recycling process includes the waste wood material reused to make new products or to generate energy at the end of its service life [19]. Technological advancement in the wood industry may result in more carbon from the forest sector ending up in the wood products by reduce processing residuals, extended service life of each end-use wood product, and an increase in the recycling rate, which can significantly expand the wood products carbon pool size [20]. To estimate the size of a wood products carbon pool and its interannual stock changes, monitoring carbon inflow and outflow rates is the most popular approach [21]. Carbon in harvested timber initially flows into the overall wood products pool, and then allocated among the different products such as construction material, furniture, paper, and biofuel [22]. The end-use wood product is disposed of when it reaches the end of its service life. A part of the disposed wood products will be recycled to make new products or directly burned as biofuel to generate energy, and the remainder will be disposed to landfills. Waste wood materials in landfills will be slowly decomposed and the carbon released to the atmosphere. Therefore, using the life cycle of each wood product is an efficient method to realize the estimation of wood products carbon pool size over time. In this study, we developed a life cycle and product type based estimator for quantifying the amount and interannual change in wood products carbon storage using the annual production of each product type, a service life based disposal method, a time-dependent recycling process, and a time-dependent decomposition approach for waste wood materials in landfills. To evaluate the performance of this estimator, we applied it to (1) account for the carbon storage in wood products produced by timber harvested in Maine, USA from 1961 to 2019 (system boundary: production approach) and (2) estimate the carbon storage in wood products consumed in the United States over the period of 1961–2020 (system boundary: stock-change approach).

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Fig. 1 The structure, carbon pools, and carbon ﬂux processes in the Wood Products Carbon Storage Estimator (WPsCS Estimator). Note that the biochar is non-energy use biochar

Methods Wood products carbon storage estimator

To account for the carbon stored in wood products including end-use products (e.g., building, furniture, and paper), charcoal, and waste wood materials in landfills, we developed the Wood Products Carbon Storage Estimator (WPsCS Estimator). WPsCS Estimator is operated at an annual time scale. The input data to run the Estimator consists of the annual consumption or production of wood product types within the user-defined system boundary including bioenergy, biochar, paper products (i.e., newspaper, graphic paper, packing paper, and household paper), building, exterior use, and home application. These wood product types are aggregated in three carbon pools: charcoal, end-use products, and landfill carbon (Fig. 1). According to the similarity of service life for different end-use wood products, the end-use wood products carbon pool is categorized to four subpools

(i.e., paper, building, exterior-use, and home application), and the paper carbon subpool is further classified into newspaper, graphic paper, packing paper, and household paper. Finally, the landfill carbon pool is accounted for using four subpools: waste paper, building, exterior use, and home application materials carbon pools. In WPsCS Estimator, the annual carbon input to the charcoal carbon pool consists of the production of nonenergy use biochar and the charcoal formed by biofuel combustion (Fig. 1). Biofuel combustion directly releases most of the carbon to the atmosphere while, at the same time, a small portion of biomass is thermochemically converted to recalcitrant charcoal. To estimate the charcoal created by biofuel burning, a combustion efficiency is employed in the estimator. The combustion efficiency represents the portion of biofuel that is completely burned, and the remainder is converted to charcoal. Because the four paper products in the paper carbon pool are significantly different in their service lives, they

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are accounted for separately in the estimator. The building subpool stores carbon in wood products used in construction. The exterior-use carbon pool represents the wood products that are employed out-of-doors such as wood dock and railway tie. The home application carbon pool includes wood products used inside such as furniture and wood floor. Each of these subpools is assigned a service life in the estimator, and when the end-use wood product reaches the end of its service life, it will be disposed (Fig. 1). The disposed wood product can be recycled to create new products, used as biomass fuel, or directly disposed to landfills. Waste wood products in landfills will be decomposed and the carbon is eventually released to the atmosphere after a decaying period.

Wood products carbon flux

Because charcoal is chemically and biologically stable, it has a relatively long residence time in the environment [23]. Therefore, although the annual production of nonenergy use biochar and charcoal formed by biofuel burning is relatively small, the magnitude of charcoal carbon pool represents a potentially signiﬁcant long-term sink of atmospheric CO2 [24]. The carbon stored in the charcoal pool can be released to the atmosphere by recombustion and decomposition. To model the annual loss from the charcoal carbon pool, a pool-size based approach is employed in WPsCS Estimator (Eq. 1) [24].

ρcha = τ + σ × ln(Ccha )

√ ×e e 2π

−β×(tw −γ )2 γ

j−i 0

√ ×e e 2π

(1)

(2)

−β×(tw −δ)2 δ

d tw

(3)

where ρwp is the annual disposal rate for a type of wood products (fraction of the pool), α and β are fitted coefficients (unitless), γ is the service half-life (year) of the product type, and tw is the time since production (year). In year j, Cr (kg) represents the remaining carbon in the wood products pool that was produced in year i, and Cw (kg) is the total carbon in these wood products produced in year i. A portion of the end-of-life wood materials will be recycled to make new wood products or reused as biofuel, with the remainder disposed to landfills. In WPsCS Estimator, most paper products can be recycled or used as biofuel to generate energy, but wood products for exterior use and household paper are not considered for recycling. Instead, exterior use and household paper wood products are directly disposed to landfills. The recycling rates for wood products are highly dependent on the technology advancement of the wood industry [26]; therefore, to represent the technological advancement in the wood industry influence on recycling rates of disposed wood products, a time-dependent approach is employed in the estimator (Eq. 4) [20]. This recycling rate includes both the carbon reused to make new wood products and as biofuel.

r = + μ × ln(k)

where ρcha is the annual charcoal loss rate (fraction of the pool), τ is the basic loss rate, σ is the pool-size related loss rate, and Ccha is the carbon pool size of charcoal (kg). The carbon storage lifetimes vary significantly among the different end-use wood products, from short-term directly disposed wood products such as household paper to long-lasting building materials [25]. To model the annual disposal rate for different wood products, a service-life based approach is used in WPsCS Estimator. This method incorporates the time since production and average service half-life, along with a Chi-squared regression model to estimate the annual disposal rate (Eq. 2) [4, 20]. Therefore, for a given type of end-use wood product made in year i, the carbon remaining in in year j is accounted for in the product pool that has not reached its service life (Eq. 3) (Integration of Eq.2).

ρwp =

Cr = Cw −

(4)

where r is the recycling rate for a type of recyclable wood products, is the recycling rate in the first year (initial year), μ represents the effect of industrial advancement on wood products recycling, and k is the order of year or the year since the initial year (i.e., 0, 1, 2 … k). The decay rate for each type of waste wood product in the landfill is primarily determined by its physical and chemical characteristics [27]. For example, waste paper has a shorter turnover time than does waste building materials and so are tracked as four separate subpools in WPsCS Estimator. The annual decay rate for each type of waste wood product is modeled by the time since disposition (year) and turnover time (years), along with a lognormal regression model (Eq. 5) [27, 28]. The turnover time is the entire period (number of years) required for the waste wood product in the landfill to be completely decomposed and emitted to the atmosphere.

ρlf = ξ ×

ln(tl ) √ ω × 2π

(5)

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Fig. 2 Interface of the Wood Products Carbon Storage Estimator (WPsCS Estimator). The default parameters are used in the two case studies of Maine, USA, and the United States (see "Estimator application" Section). To perform an estimation, see Additional ﬁle 1

where ρlf is the annual decay rate (fraction of pool) for a type of waste wood products in the landﬁll, tl is the time (year) since disposition (i.e., 0, 1, 2 … ω ), ξ is basic decay rate, and ω is the turnover time (year).

The estimator interface

The WPsCS Estimator is developed using Python programming, and it has a user-friendly interface for its operation (Fig. 2). The data containing the wood product carbon input consists of a comma-separated value (CSV) ﬁle including the annual production, consumption, or user-deﬁned system boundary of each wood

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product (in kg C per year) including non-energy use biochar, building, exterior use, home application, and paper carbon pools. The input wood product data includes products made from harvested timber and recyclable waste wood materials when the system boundary includes the products made from recycled waste wood materials. Parameters including the combustion efficiency of biofuel, charcoal decay rate, disposal rate for each end-use wood product, recycling rate for each recyclable wood product, and decay rate for each type of waste wood material in landfills can be manually calibrated by users (To perform an estimation, see Additional file 1). Estimator application

The WPsCS Estimator was applied to estimate the carbon stored in wood products produced by timber harvested in Maine, USA, over the period of 1961–2019. For this estimation, the production system boundary was employed, meaning that all carbon in wood products harvested in Maine was accounted for regardless of whether it was used in Maine or elsewhere. The timber harvesting data were obtained from the Maine Department of Agriculture Conservation and Forestry (Fig. 3a). To obtain the production of each type of wood products, the allocation method proposed by Li et al. [20] was used. Because this allocation method does not categorize the paper products, the annual fraction of newspaper, graphic paper, packing paper, and household paper of the entire United States provided by the FAOSTAT database [29] was used to allocate paper products. For a second demonstrative application, the estimator was applied to calculate the carbon storage in wood products consumed in the United States. For this estimation, we used the stock-change system boundary, which estimates the carbon stock in wood products consumed and physically located in the United States, while the wood products exported internationally are not counted. The annual domestic product, as well as the import and export of biofuel, non-energy use biochar, sawlog, structured panel, non-structural panel, paperboard, and paper products in the United States during the period of 1961 to 2020 were obtained from the FAOSTAT database [29]. Therefore, the consumption of each wood product in the United States was calculated as the total of the commercial balance (the diﬀerence between import and export) and domestic product (Eq. 6). To allocate these second wood products including sawlog, structured panel, nonstructured panel, and paperboard to end-used wood products (Fig. 3b), we applied the consumed solid wood timber products in major end-use markets data in the United States provided by McKeever and Howard [30] and Alderman [31].

Fig. 3 The annual production of wood products made from the timber harvested in Maine, USA during the period of 1961–2019 (a), and the annual consumption of wood products in the United States from 1961 to 2020 (b)

Wc = (Wi − We ) + Wproduct

(6)

where Wc is the annual consumption of a wood product in the United States, Wi is the imported wood product, We is the exported wood product, and Wp is the domestic wood product produced in the United States. Estimator parameterization

Parameters for the WPsCS Estimator can be obtained from expert knowledge and industry surveys or life cycle inventories, but the use of parameters from previous studies is a common practice [32, 33]. To realize the two estimations demonstrated here, we developed a set of parameters including the combustion efficiency, charcoal decay rate, disposal rates for end-use wood products, recycling rates for recyclable disposed wood materials, and decay rates for waste wood products in landfills. The combustion efficiency was obtained from published studies [34–37] and it is an average value for both industrial fuel and residential fuel (Table 1). The charcoal loss rate

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Table 1 Parameters including the combustion eﬃciency, charcoal decay rates, disposal rates for end-use wood products, recycling rates for recyclable disposed wood materials, and decay rates for waste wood products used to estimate the carbon stored in wood products made from the timber harvested in Maine, USA, and the carbon stored in the wood products consumed in the United States Biofuel Biochar

Biofuel and charcoal Combustion eﬃciency

96%

Charcoal decay(τ )

0.007

Charcoal decay(σ ) Disposal rate

Recycle rate

End-use wood product

0.0003 α

Building

0.133

0.028

Exterior use

0.326

0.041

Home application

0.265

0.031

Newspaper

3.062

0.0

Graphic paper

1.006

0.0

Packing paper

6.036

0.0

Household paper

12.036 0.0

Disposed wood product

0.5

Building

0.085

0.015

Home application

0.085

0.016

Newspaper

0.225

0.027

Graphic paper

0.225

0.027

Packing paper

0.225

0.027

Landﬁll decay rate Waste wood material ξ

Building

0.997

Exterior use

1.178

Home application

1.329

Paper

0.821

including decay and reburn rates and related parameters were obtained from global studies conducted by Wei et al. [24] and Landry and Matthews [38] (Table 1). The service half-life for each type of end-use wood product was reviewed from published studies that were conducted in the United States [e.g., 39, 40] (Table 1; Fig. 4a). In the United States, the recycling rate of waste wood materials was obtained from the solid wood products recycling data provided by the United States Environmental Protection Agency (EPA). We suggested that the recycling rate of waste wood materials started from 1961 at a rate of 8.5% and increased to be 14.8% in 2020. The data were used to parameterize the recycling rate regression model (Eq. 4). We employed the same recycling regression model for building and home application wood products (Table 1; Fig. 4b). According to the EPA paper recycling information, the paper recycling rate was estimated as 22.5% in 1961 and signiﬁcantly increased to a rate of 33.5% in 2020. These rates were used to parametrize the

Fig. 4 Disposal rates for building, exterior use, and home application wood products (a), the recycling rates for solid waste wood materials (building and home application wood products) and paper products (newspaper, graphic paper, and packing paper) (b), and decay rates for waste building, exterior use, home application, and paper wood products in landﬁlls (c)

paper recycling regression model, and the parameterized model was then employed for all recyclable paper products including newspaper, graphic paper, and packing paper (Table 1; Fig. 4b). To parameterize the decay regression model for waste wood products in landﬁlls, we drew from the results of several prior studies [i.e., 27, 28] [41–43] (Table 1; Fig. 4c).

Results The carbon stored in wood products made from the timber harvested in Maine, USA, accumulated to 35.89 Tg C from 1961 to 2019, equivalent to an average annual net sink of 0.61 Tg C (Fig. 5a). In 2019, the paper wood products carbon pool had the smallest accumulated size (1.28 Tg C), and the building pool was the largest (16.29 Tg C). Although the average annual production of paper products was 33.31% of the total wood products, due to the fast turnover rate they formed the smallest end-use wood products carbon pool. The home application carbon pool had the second largest size of 9.03 Tg C. Charcoal had the least annual production at an average rate of 0.05 Tg C; however, due to its resistant property charcoal was accumulated to a relatively signiﬁcant stock representing 6.84% (2.45 Tg C) of the estimated total accumulated carbon storage in Maine-harvested wood products over the period of

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Fig. 5 The accumulated carbon storage in wood products made from the timber harvested in Maine, USA, during the period of 1961– 2019 (a), and the accumulated carbon storage in wood products consumed in the United States during the period of 1961–2020 (b)

analysis. In addition, landﬁll carbon pool stored 4.58 Tg C (12.76%). The carbon stored in wood products consumed in the United State during the period of 1961–2020 was calculated as 2607 Tg C with an average annual accumulation rate of 43.4 Tg C (Fig. 5b). In 2020, 73.1% (1905.2 Tg C) of the carbon was stored in the building wood products pool, representing the largest end-use pool. Charcoal had the least amount of carbon storage (32.7 Tg C) while paper products had a larger size of 42.4 Tg C. Home application wood products and landﬁll carbon pool had similar sizes at 252.7 and 256.5 Tg C, respectively, accumulated in the United States over the period of this analysis.

Discussion Li et al. [20] reported a carbon storage of 40.3 Tg C in wood products made from the harvested timber in Maine, USA, in the same period, which is higher than

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our estimates. This is mainly due to the longer service life (15 years) for all paper products employed in their estimation. Skog [44] applied the stock change approach and found that the carbon stock in wood products in the United States increased to 44 Tg C in 2005, while our estimate suggested an increase of 56 Tg C from 1961 to 2019. This is because Skog [44] employed a shorter service life (2 years) for all paper products, did not include the charcoal carbon pool, and applied a faster turnover approach to model the decomposition of waste wood materials in landfills. Zhang et al. [4] reported that the carbon accumulated in end-use wood products in the United States was estimated to be 818 Tg C from 1992 to 2015, which is similar to our result (797 Tg C). Overall, the WPsCS Estimator can successfully account for the carbon stored in wood products. As a part of the lateral carbon export from forest ecosystems [45], accounting for the carbon storage in wood products is required to reconcile the discrepancy between bottom-up estimates of carbon stock change with top-down estimates of landatmosphere carbon exchange [46, 47]. This estimator can be widely applied to quantify carbon stock changes. The bucking allocation processes that transfers carbon from primary to secondary and ultimately to end-use wood products are omitted in the estimator. Because the production of each type of end-use wood products has significant interannual dynamics, it is a challenge to use a single regression model or a fraction to represent the allocation process over a longer time period [21, 48]. Therefore, the off-the-shelf allocated wood products data is required for the estimator. The service life for each type of wood product is a critical parameter needed for quantifying the carbon stored in end-use wood products. In this study, parameters obtained from studies conducted in the United States are used to quantify the wood products carbon storage for both Maine and the United States. The service life of each type of wood product varies by region. For example, the service life of wood products used for home application is highly correlated with household income [4, 49], and they have longer service lives in developed countries than developing countries. Therefore, region-specific parameters are essential to obtaining reliable estimates. Ignoring the recycling process may overestimate the carbon inflow rate for the landfill carbon pool; therefore, is essential to include the recycling process in wood products carbon budget estimations. The WPsCS Estimator uses a timedependent approach to represent the effect of the Industrial Revolution on the waste wood materials recycling. But the processes that use recycled wood products to make new wood products or used as biofuel to generate energy are not modeled in WPsCS Estimator. Thus, the input data should include the wood products made with

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recycled wood materials or the system boundary should be clariﬁed before organizing the input data.

Conclusion The goal for developing the WPsCS Estimator is to efficiently and easily quantify the carbon stored in harvested wood products for a given region over a specific period, which was demonstrated with two illustrative examples. WPsCS Estimator has a user-friendly interface, and all parameters can be easily modified. Because the bucking allocation process is excluded in the estimator, the allocated end-use wood products data is required. This exclusion increases the work to prepare the input data, but it can make the results more reliable. We employed time-dependent methods for the recycling process, which can partially incorporate the influence of technological advancement in the wood industry on waste wood materials recycling. Meanwhile, technological advancement also can extend the service life of wood products used for building and home application [50]. The current simulator uses a constant service life for the entire simulation; therefore, it is weak in representing this effect. Despite these noted limitations, the WPsCS Estimator has broad utility and application for policymakers and practitioners to quantify the impact of wood product processing, consumption, and recycling on local, regional, and global carbon stocks. Abbreviation WPsCS Estimator

Wood products carbon storage estimator

Supplementary Information The online version contains supplementary material available at https://doi. org/10.1186/s13021-022-00220-y. Additional file 1: Text 1. Description of the WPsCS Estimator. Table S1. Parameters include the combustion eﬃciency, charcoal decay rates, disposal rates for end-use wood products, recycling rates for recyclable disposed wood materials, and decay rates for waste wood products. (These parameters are used for the United States. See the main article to obtain the details for each parameter.)

Acknowledgements This work was supported by the NASA Carbon Monitoring System grant 80NSSC21K0966. In addition, this work was supported in part by a grant from the USDA Forest Service, Northeastern States Research Cooperative, under University of Vermont subcontract AWD00051. We thank Dr. Ling Li for helpful comments on this article. Author contribution XW conceptualized, designed, developed, and tested the simulator. DJH supervised this project. JZ collected the data. XW interpreted the results and wrote the original manuscript. XW, JZ, DJH, AD, and HZ edited the manuscript. All authors read and approved the ﬁnal manuscript. Availability of data and materials The harvesting data of Maine, USA is obtained from Maine Forest Service and Department of Agriculture, Conservation and Forestry (https://digitalmaine.

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com/for_docs/index.html). The consumed primary wood products of the United Stated is obtained from the Food and Agriculture Organization of the United Nations (https://www.fao.org/faostat/en/#data/FO). The data used to fit recycling rate regression models were obtained from the United States Environmental Protection Agency (EPA) (https://www.epa.gov/facts-and-figur es-about-materials-waste-and-recycling/national-overview-facts-and-figur es-materials#recycling). Code and Software Availability The Wood Products Carbon Storage Estimator (WPsCS Estimator) was developed by Python programming and the estimator can be accessed in GitHub (https://github.com/xinyuanwylb19/WPsCS-Estimator).

Declarations Competing interests The authors declare no competing interests.

Received: 31 October 2022 Accepted: 8 December 2022

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15. Fortin M, Ningre F, Robert N, Mothe F. Quantifying the impact of forest management on the carbon balance of the forest-wood product chain: a case study applied to even-aged oak stands in France. For Ecol Manag. 2012;279:176–88. 16. Richards GP, Borough C, Evans D, Reddin A, Ximenes F, Gardner D. Developing a carbon stocks and flows model for australian wood products. Australian Forestry. 2007;70(2):108–19. 17. Uusitalo J. A framework for CTL method-based wood procurement logistics. Int J For Eng. 2005;16(2):37–46. 18. Donlan J, Skog K, Byrne KA. Carbon storage in harvested wood products for Ireland 1961–2009. Biomass Bioenergy. 2012;46:731–8. 19. Smith RL, Shiau R-J. An industry evaluation of the reuse, recycling, and reduction of spent CCA wood products. For Prod J. 1998;48(2):44. 20. Li L, Wei X, Zhao J, Hayes D, Daigneault A, Weiskittel A, Kizha AR, ONeill SR. Technological advancement expands carbon storage in harvested wood products in Maine, USA. Biomass Bioenergy. 2022;161:106457. 21. Dymond CC. Forest carbon in North America: annual storage and emissions from British Columbia’s harvest, 1965–2065. Carbon Balance Manag. 2012;7(1):1–20. 22. Zhao J, Wei X, Li L. The potential for storing carbon by harvested wood products. Front Forests Global Change. 2022. https://doi.org/10.3389/ffgc. 2022.1055410. 23. Bird MI, Wynn JG, Saiz G, Wurster CM, McBeath A. The pyrogenic carbon cycle. Annu Rev Earth Planet Sci. 2015;43:273–98. 24. Wei X, Hayes DJ, Fraver S, Chen G. Global pyrogenic carbon production during recent decades has created the potential for a large, long-term sink of atmospheric CO2. J Geophys Res Biogeosci. 2018;123(12):3682–96. 25. Profft I, Mund M, Weber G-E, Weller E, Schulze E-D. Forest management and carbon sequestration in wood products. Eur J For Res. 2009;128(4):399–413. 26. Trochu J, Chaabane A, Ouhimmou M. Reverse logistics network redesign under uncertainty for wood waste in the CRD industry. Resour Conserv Recycl. 2018;128:32–47. 27. Cruz FBDl, Barlaz MA. Estimation of waste component-specific landfill decay rates using laboratory-scale decomposition data. Environ Sci Technol. 2010;44(12):4722–8. 28. Barlaz MA. Carbon storage during biodegradation of municipal solid waste components in laboratory-scale landfills. Glob Biogeochem Cycles. 1998;12(2):373–80. 29. FAOSTAT. Food and agriculture organization of the United Nations, FAOSTAT forestry database. 2020. https://www.fao.org/forestry/statistics/ 84922/en/. Accessed 30 Sep 2022. 30. McKeever DB, Howard JL. Solid wood timber products consumption in major end uses in the United States, 1950–2009: a technical document supporting the Forest Service 2010 RPA Assessment. Madison (WI); Gen Tech Rep FPL–199; 2011. 31. Alderman D. US forest products annual market review and prospects 2015–2021. FPL-GTR-289. 2022;289:1–31. 32. Eriksson E, Gillespie AR, Gustavsson L, Langvall O, Olsson M, Sathre R, Stendahl J. Integrated carbon analysis of forest management practices and wood substitution. Can J For Res. 2007;37(3):671–81. 33. Seidl R, Rammer W, Jäger D, Currie WS, Lexer MJ. Assessing tradeoffs between carbon sequestration and timber production within a framework of multi-purpose forestry in Austria. For Ecol Manag. 2007;248(1–2):64–79. 34. Czimczik CI, Preston CM, Schmidt MWI, Schulze ED. How surface fire in siberian scots pine forests affects soil organic carbon in the forest floor: stocks, molecular structure, and conversion to black carbon (charcoal). Glob Biogeochem Cycles. 2003. https://doi.org/10.1029/2002GB001956. 35. Pingree MR, Homann PS, Morrissette B, Darbyshire R. Long and shortterm effects of fire on soil charcoal of a conifer forest in southwest Oregon. Forests. 2012;3(2):353–69. 36. Kauffman JB, Cummings D, Ward D, Babbitt R. Fire in the brazilian amazon: 1. biomass, nutrient pools, and losses in slashed primary forests. Oecologia. 1995;104(4):397–408. 37. Kuhlbusch TAJ, Crutzen PJ. Black carbon, the global carbon cycle, and atmospheric carbon dioxide. Biomass Burning and Global Change. 1996;1:160–9. 38. Landry JS, Matthews HD. The global pyrogenic carbon cycle and its impacton the level of atmospheric CO2 over past and future centuries. Glob Chang Biol. 2017. https://doi.org/10.1111/gcb.13603.

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39. Skog KE, Nicholson GA. Carbon sequestration in wood and paper products. In: Joyce, L.A., Birdsey R. (eds). The impact of climate change on America’s forests: a technical document supporting the 2000 USDA Forest Service RPA assessment. USDA For. Serv., Gen. Tech. Rep. RMRSGTR-59, Rocky Mountain Research Station, Fort Collins, CO, USA. 2006;133:79 – 88. 40. Smith JE, Heath LS, Skog KE, Birdsey RA. Methods for calculating forest ecosystem and harvested carbon with standard estimates for forest types of the United States. Newtown Square: US Department of Agriculture, Forest Service, Northeastern Research Station; 2006. 41. Micales JA, Skog KE. The decomposition of forest products in landfills. Int Biodeterior Biodegrad. 1997;39(2–3):145–58. 42. Jambeck J, Weitz K, Solo-Gabriele H, Townsend T, Thorneloe S. CCAtreated wood disposed in landfills and life-cycle trade-offs with waste-toenergy and MSW landfill disposal. Waste Manag. 2007;27(8):21–8. 43. Duan H, Song G, Qu S, Dong X, Xu M. Post-consumer packaging waste from express delivery in China. Resour Conserv Recycl. 2019;144:137–43. 44. Skog KE. Sequestration of carbon in harvested wood products for the United States. For Prod J. 2008;6(2):56–72. 45. Ciais P, Borges A, Abril G, Meybeck M, Folberth G, Hauglustaine D, Janssens I. The impact of lateral carbon fluxes on the european carbon balance. Biogeosciences. 2008;5(5):1259–71. 46. Wei X, Hayes DJ, Fernandez I. Fire reduces riverine DOC concentration draining a watershed and alters post-fire DOC recovery patterns. Environ Res Lett. 2021;16(2):024022. 47. Wei X, Hayes DJ, Fernandez I, Fraver S, Zhao J, Weiskittel A. Climate and atmospheric deposition drive the inter-annual variability and long-term trend of dissolved organic carbon flux in the conterminous United States. Sci Total Environ. 2021;771:145448. 48. Rüter S. Projection of net-emissions from harvested wood products in european countries. in work report of the institute of wood technology and wood biology, report no: 2011/1 Vti, editors, Hamburg: Germany. 2011. p. 63 49. Brack D. Sustainable consumption and productionof forest products. in proceedings of the thirteenth session of the UnitedNations Forum on Forests, New York; NY, USA. 2018. p. 7-11. 50. McKinley DC, Ryan MG, Birdsey RA, Giardina CP, Harmon ME, Heath LS, Houghton RA, Jackson RB, Morrison JF, Murray BC. A synthesis of current knowledge on forests and carbon storage in the United States. Ecol Appl. 2011;21(6):1902–24.

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Volume 9, Number 3, 2023

Paper Meets Plastic: The Perceived Environmental Friendliness of Product Packaging TATIANA SOKOLOVA, ARADHNA KRISHNA & TIM DÖRING Packaging waste makes up more than 10% of the landfilled waste in the United States. While consumers often want to make environmentally friendly product choices, we find that their perceptions of the environmental friendliness of product packaging may systematically deviate from its objective environmental friendliness. Eight studies (N ¼ 4,103) document the perceived environmental friendliness (PEF) bias whereby consumers judge plastic packaging with additional paper to be more environmentally friendly than identical plastic packaging without the paper. The PEF bias is driven by consumers’ “paper ¼ good, plastic ¼ bad” beliefs and by proportional reasoning, wherein packaging with a greater paper-to-plastic proportion is judged as more environmentally friendly. We further show that the PEF bias impacts consumers’ willingness to pay and product choice. Importantly, this bias can be mitigated by a “minimal packaging sticker” intervention, which increases the environmental friendliness perceptions of plastic-only packaging, rendering plastic-packaged products to be preferable to their plastic-plus-paper-packaged counterparts. This research contributes to the packaging literature in marketing and to research on sustainability while offering practical implications for managers and public policy officials. Baruch College, Drexel University, Florida State University, Northeastern University, University of Miami, Marketing in Israel conference, and from discussions at the Tilburg School of Economics and Management Consumer Club. Supplementary materials are included in the web appendix accompanying the online version of this article. Journal of Consumer Research, Inc., Vol.50, 2023 https://doi.org/10.1093/jcr/ucad00 This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/),

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Article 8 – Packaging

Paper Meets Plastic: The Perceived Environmental Friendliness of Product Packaging

Packaging waste makes up more than 10% of the landfilled waste in the United States. While consumers often want to make environmentally friendly product choices, we find that their perceptions of the environmental friendliness of product packaging may systematically deviate from its objective environmental friendliness. Eight studies (N ¼ 4,103) document the perceived environmental friendliness (PEF) bias whereby consumers judge plastic packaging with additional paper to be more environmentally friendly than identical plastic packaging without the paper. The PEF bias is driven by consumers’ “paper ¼ good, plastic ¼ bad” beliefs and by proportional reasoning, wherein packaging with a greater paper-to-plastic proportion is judged as more environmentally friendly. We further show that the PEF bias impacts consumers’ willingness to pay and product choice. Importantly, this bias can be mitigated by a “minimal packaging sticker” intervention, which increases the environmental friendliness perceptions of plastic-only packaging, rendering plastic-packaged products to be preferable to their plastic-plus-paper-packaged counterparts. This research contributes to the packaging literature in marketing and to research on sustainability while offering practical implications for managers and public policy officials. Keywords: sustainability, packaging, cognitive biases, heuristics

aste from packaging poses a serious environmental problem. The US Environmental Protection Agency reports that there were more than 80 million tons of packaging produced in 2018, with two-thirds of this packaging made of plastic or paper. Once the packaging is no longer in use, some of it is recycled, but much of it ends up in

landfills. In 2018 alone, landfilled plastic and paper packaging waste amounted to 10.09 and 6.44 million tons, respectively, accounting for 11% of the total landfilled waste in the United States (United States Environmental Protection Agency 2020). Despite the potential environmental and financial benefits of reducing excessive packaging (Deutsch 2007; Elgaaı̈ed-Gambier 2016), many products remain

Tatiana Sokolova (t.sokolova@tilburguniversity.edu) is an assistant professor of marketing at the Tilburg School of Economics and Management, 5037 AB Tilburg, Netherlands. Aradhna Krishna (aradhna@umich.edu) is the Dwight F. Benton Professor of Marketing at the Ross School of Business, University of Michigan, Ann Arbor, MI 48109, USA. Tim Döring (tim.doring@maastrichtuniversity.nl) is an assistant professor of marketing at the School of Business and Economics, Maastricht University, 6211 LM Maastricht, Netherlands. Please address correspondence to Tatiana Sokolova or Aradhna Krishna. The authors thank the editor, the associate editor, and three reviewers for their guidance. The authors also thank Yesim Orhun and Max Pachali for their feedback and advice on statistical analyses; Maura Scott for suggesting the intervention manipulation; and Tetiana Bychkova for gathering the packaging images from the Spanish market. This research has benefited from feedback at various seminars and conferences, including seminars at

Baruch College, Drexel University, Florida State University, Northeastern University, University of Miami, Marketing in Israel conference, and from discussions at the Tilburg School of Economics and Management Consumer Club. Supplementary materials are included in the web appendix accompanying the online version of this article.

Editor: Markus Giesler Associate Editor: Oleg Urminsky Advance Access publication January 28, 2023

C The Author(s) 2023. Published by Oxford University Press on behalf of Journal of Consumer Research, Inc. V This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com Vol. 50 2023 https://doi.org/10.1093/jcr/ucad008

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with additional paper packaging (i.e., plastic-plus-paper packaging). We argue and show empirically that consumers tend to perceive overpackaged products, wrapped in plastic plus paper, as having more environmentally friendly packaging than their plastic-only-wrapped counterparts. We refer to this effect as the perceived environmental friendliness (PEF) bias. We demonstrate that the PEF bias is driven by consumers’ “paper ¼ good, plastic ¼ bad” beliefs and by proportional reasoning, wherein packaging with a greater paper-to-plastic proportion is judged as more environmentally friendly. As a result of this evaluation process, holding the amount of plastic in product packaging fixed, adding more paper to it leads to higher perceived environmental friendliness, even though objective environmental friendliness decreases. Importantly, the PEF bias has downstream consequences for consumers’ willingness to pay and product choice, such that consumers are willing to pay more for products packaged with additional layers of paper and are more likely to choose them compared to their

TABLE 1 EXAMPLES OF PLASTIC-PLUS-PAPER- AND PLASTIC-PACKAGED PRODUCTS

NOTES.—Packaging examples from different grocery stores and pharmacies. Each row features four different pairs of products where the left product is packaged in plastic plus paper and the right product is packaged in plastic only.

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overpackaged, with layers of superfluous packaging added to the more necessary ones. Examples of overpackaged products can be found across product categories and geographic markets (table 1). For example, Nivea sells body lotion packaged in plastic and cardboard boxes, even though a similar product from the same brand is available in plastic tubes only. By the same token, Sensodyne toothpaste is commonly sold in plastic tubes with additional paper packaging, while the same brand already sells toothpaste without paper boxes. We present a more extensive list of examples of overpackaging in web appendix A. Besides specific brands engaging in overpackaging, there are entire product categories where addition of layers of superfluous packaging is common. Breakfast cereal is often packaged first in plastic bags and then in cardboard boxes; plastic yogurt multipacks are covered with additional cardboard sleeves; and skincare products are placed within paper boxes. In this article, we examine consumer responses to product overpackaging, focusing on consumer perceptions of plastic packaging versus plastic packaging

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paper cartons for their products. Similarly, Procter & Gamble eliminated cardboard box packaging for their Crest toothpaste; and Nestle Waters, North America, switched to narrower paper labels on their bottles, an initiative saving the company over 20 million pounds of paper over a 5-year period (Deutsch 2007). However, our findings across multiple product categories suggest that when companies eliminate paper packaging in plastic-packaged products, they may be penalized by consumers who will perceive plastic-only packaging as less, and not more, environmentally friendly. Critically, we find that explicitly stating that a given product uses minimal packaging via, for example, on-package stickers, attenuates the perceived environmental friendliness bias in packaging evaluations and choice. As such, our work underscores the importance of combining companies’ packaging waste reduction initiatives with marketing communications that draw consumer attention to the amount of packaging used in minimally packaged products. Finally, our work has implications for policymakers and non-governmental organizations (NGOs). Elimination of superfluous packaging will reduce the amount of greenhouse gas emissions from both the production and disposal of product packaging. One of the proposed ways to reduce environmental waste is through a pre-cycling strategy, wherein consumers consciously reduce waste by not buying overpackaged products (Elgaaı̈ed-Gambier 2016). Our work suggests that shifting responsibility toward consumers may not be a very successful strategy of packaging waste reduction, since consumers’ perception of the environmental friendliness of packaging may not align with its objective environmental friendliness. Asking managers to eliminate superfluous packaging may not work either. As noted earlier, managers may be disincentivized to eliminate unnecessary paper packaging, because the addition of paper packaging can boost their customers’ environmental friendliness evaluations, willingness to pay, and choice. Our intervention study, however, suggests that a “minimal packaging” sticker can correct consumer perceptions of environmental friendliness of product packaging and boost demand. Thus, governments and NGOs may consider introducing minimal packaging certifications and onpackage labels that would motivate consumers to buy and, consequently, incentivize companies to offer minimally packaged products. In the next sections, we build our predictions and report eight experiments testing our theorizing. We conclude by discussing the theoretical and practical implications of this research.

CONCEPTUAL FRAMEWORK We propose that consumers will perceive the objectively less environmentally friendly plastic-plus-paper packaging

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plastic-packaged alternatives. Finally, we introduce an actionable “minimal packaging sticker” intervention, which increases the environmental friendliness perceptions of plastic-only packaging and makes consumers more likely to choose plastic-packaged products over their plastic-plus-paper overpackaged counterparts. We note that our findings can be generalized beyond the context of overpackaging: driven by “paper ¼ good, plastic ¼ bad” beliefs and proportional reasoning, people will likely perceive mixed packaging, where paper partially replaces plastic (e.g., paper packaging with a small plastic window), to be more environmentally friendly than plasticonly packaging. However, while mixed packaging can increase the objective environmental friendliness of packaging overall, overpackaging, where paper is added to fixed amounts of plastic, does not. As such, it is particularly important to examine consumers’ responses to overpackaged goods to understand whether and when their perceptions of packaging environmental friendliness will diverge from objective reality. Our research contributes to the packaging literature in marketing. Several studies show that packaging design characteristics, such as packaging size (Argo and White 2012; Coelho do Vale, Pieters, and Zeelenberg 2008), shape (Chandon and Ordabayeva 2009), color (Mai, Symmank, and Seeberg-Elverfeldt 2016), and front-ofpack labeling (Dubois et al. 2021), affect consumers’ purchase decisions and consumption. We add to the above line of work by showing how packaging composition—plastic only versus plastic plus paper—affects consumers’ evaluations of product packaging and shapes their willingness to pay and choice. Moreover, our work adds to the emerging literature on consumer behavior and sustainability. Research suggests that perceived environmental friendliness of products and product packaging influences consumer judgments and choice. It can increase food quality perceptions (Magnier, Schoormans, and Mugge 2016), improve overall brand attitudes (Olsen, Slotegraaf, and Chandukala 2014), and increase product usage rates (Lin and Chang 2012). At the same time, perceived environmental friendliness can reduce preference for products with strength-related attributes (Luchs et al. 2010) and reduce perceived product efficacy (Lin and Chang 2012). Critically, much less is known about how consumers come to perceive a product or product packaging as environmentally friendly in the first place (for exceptions, see Gershoff and Frels 2015; Reid, Gonzalez, and Papalambros 2010). We add to this work by outlining the psychological underpinnings of environmental friendliness judgments of product packaging. This research also has important practical implications. A few companies, such as premium skincare brand Kiehl’s, Procter & Gamble, and Nestle, are taking action to eliminate unnecessary packaging and reduce packaging waste. For instance, Kiehl’s avoids using unnecessary

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Objective and Perceived Environmental Friendliness Marketing and social psychology research outlines several ways to make consumer behaviors more sustainable— from making environmentally friendly product choices more socially desirable, to rewarding these choices with monetary incentives, to discouraging environmentally unfriendly ones by anticipated guilt (White, Habib, and Hardisty 2019). Importantly, the research also indicates that often consumers cannot objectively assess the environmental footprint of different products, meaning that their understanding of what constitutes a sustainable or environmentally friendly product choice may be limited or incorrect. For instance, Gershoff and Frels (2015) demonstrate that products with identical environmental benefits are judged differently, depending on whether the green benefits stem from more versus less central product attributes. As such, holding the overall amount of recycled materials in a product constant, consumers are more likely to view a waffle maker (that can also make paninis) as more environmentally friendly when its waffle plates are made of 90% recycled aluminum, compared to when its panini plates are. In another study attesting to the subjective nature of consumers’ environmental friendliness perceptions, Reid et al. (2010) show that product designs that have fewer abrupt line changes are perceived as inspired by nature and, consequently, are erroneously seen as more environmentally friendly. While this prior research focuses on the products’ environmental friendliness, it has bearing on the products’ packaging as well. Similar to judgments of product environmental friendliness, objective evaluations of packaging environmental friendliness require that consumers gather and integrate large amounts of information about the relative environmental footprint of different packaging materials. To illustrate, the Environment Agency of England and Whales conducted a life-cycle assessment of different supermarket carrier bags. The assessment across nine environmental impact categories, such as the global warming potential and contribution to depletion of environmental

resources, revealed that conventional plastic bags had the lowest impact in eight of the nine studied categories and that this impact largely depended on the number of times a bag was reused (Edwards and Fry 2011). Given the complexity of objective assessment of environmental friendliness, we propose that consumers will rely on simplified decision-making and use heuristics in their judgments of environmental friendliness of packaging. These heuristics could be based on consumers’ beliefs about packaging materials, which we discuss next.

Paper and Plastic Packaging Beliefs We propose that consumers’ personal experience and beliefs, as well as exposure to external cues, will facilitate a belief that paper is relatively good for the environment, while plastic is relatively bad, what we refer to as “paper ¼ good, plastic ¼ bad” belief. Personal Experience and Beliefs. First, people form the “paper ¼ good, plastic ¼ bad” belief through repeated sensory experience with paper and plastic. Blind-test data suggest that people find the touch of paper to be more pleasant than that of plastic (Klöcker et al. 2012). Similar to the formation of implicit brand attitudes based on past preferences, repeated sensory experiences may result in more positive associations for paper and more negative associations for plastic (Maison, Greenwald, and Bruin 2004). Second, “paper ¼ good, plastic ¼ bad” belief may be formed based on an intuition that paper is more natural and derived from trees, while plastic is more artificial. Driven by the “natural is better” heuristic (Hagen 2021; Meier, Dillard, and Lappas 2019), consumers can come to perceive “natural” paper as good and “unnatural” plastic as bad. At the same time, plastic packaging, a material causing less environmental harm at the production stage and arguably more harm during disposal (Edwards and Fry 2011), may be seen as substantially worse for the environment because of people’s innate tendency to perceive later-timed events as more consequential. For example, a basketball player scoring a 2-point basket at the 40th minute of a 40 minute game is seen as contributing more to the outcome of the game compared to a player scoring a basket at the 7th minute (Ziano and Pandelaere 2022). Similarly, products causing environmental harm first and benefits later (e.g., electric car made in a conventional way, but producing no emissions while driven) are seen as having more positive environmental impact than products producing environmental benefits first and causing harm later (e.g., gasoline car made with recycled materials that emits gas while driven; Hur et al. 2021). Further attesting to the idea that plastic may be seen as more environmentally harmful than paper because of its environmental footprint during disposal, in-depth interview

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as more environmentally friendly than plastic-only packaging. Our theorizing relies on three core propositions. First, we propose that objective and subjective evaluations of the environmental friendliness of product packaging may diverge. Second, we propose that in their subjective evaluations of the environmental friendliness of product packaging, consumers will rely on a “paper ¼ good, plastic ¼ bad” belief. Finally, we propose that consumers will use the “good paper-to-bad plastic” proportion, as opposed to the total amount of product packaging, to judge packaging environmental friendliness. Next, we discuss the research pertinent to these three propositions and build our specific predictions.

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data from a panel of Dutch consumers indicate that consumers largely ignore production, transportation, and storage considerations when forming their environmental friendliness evaluations and mainly focus on the postconsumption treatment of packaging waste. Consequently, they come to perceive non-returnable plastic as more environmentally harmful compared to non-returnable cardboard but perceive returnable plastic as less harmful (van Dam 1996).

Packaging Amount versus Packaging Proportions Even though consumers often lack the information needed to accurately judge packaging environmental friendliness (Gifford 2011), in most cases, they can easily see the amount of product packaging, by, for example,

examining the size of the packaging; or the number of layers used to pack a given item. Thus, packaging amount may be a likely driver of environmental friendliness perceptions, with packaging using additional layers or larger amounts of materials being deemed less environmentally friendly. Following this logic, toothpaste that comes in a plastic tube plus a paper box ought to be considered worse for the environment than toothpaste that comes in a plastic tube only. Running counter to the above “less is better” logic, the general evaluability theory suggests that people may not rely on packaging amount in their evaluations because they will have difficulty assessing whether a given amount of packaging is large or small (Hsee and Zhang 2010). For example, Hsee (1998) reports that people do not rely on the absolute size of a product in their willingness to pay judgments, because absolute size is difficult to evaluate. As a result, people become willing to pay more for a dinnerware set with 24 intact pieces compared to a set with 31 intact and 9 broken pieces and for a cup overfilled with 7 oz of ice cream compared to a cup partially filled with 8 oz of ice cream. Given that consumers may be unable to evaluate the absolute amount of product packaging when evaluating its environmental friendliness, we propose that they will rely on the paper-to-plastic proportion, a salient and easily evaluable cue, when assessing packaging environmental friendliness. In line with this logic, extant research suggests that proportional reasoning guides consumer judgments in a range of domains, from sensory perception (Garner 1953; Krishna and Hagen 2019), to gamble assessments (De Langhe and Puntoni 2015), to product evaluations (Hsee 1998). In sum, we argue that, guided by the “paper ¼ good, plastic ¼ bad” belief, people should judge packaging that consists of 100% plastic as low in perceived environmental friendliness. Critically, once a layer of “good” paper is added to a layer of “bad” plastic, the proportion of paper to plastic will increase, leading consumers to judge an objectively larger amount of packaging to be more environmentally friendly compared to a smaller amount of packaging consisting of plastic alone. We refer to this effect as the PEF bias in packaging evaluations.

OVERVIEW OF STUDIES We report eight studies supporting our theorizing (N ¼ 4,103; see table 2 for an overview). Studies 1a and 1b provide evidence of the PEF bias. They show that adding paper to a layer of plastic increases the perceived environmental friendliness of product packaging. Studies 2a and 2b test the underlying process. Study 2a shows that the effect of adding paper to plastic is stronger when the proportion of paper in product packaging increases. Study 2b

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External Cues. In addition to consumers’ sensory experiences and beliefs, several external sources facilitate the “paper ¼ good, plastic ¼ bad” belief. First, the belief is fostered by the availability of paper bags and unavailability of plastic bags in grocery stores purporting to be more environmentally friendly, such as Whole Foods and Trader Joe’s (Dapcevich 2019; Martin 2008). By the same token, the belief is strengthened by paper packaging of foods positioned in terms of their “all natural ingredients.” To illustrate, several small organic coffee brands (e.g., Real Good Coffee Co., Fresh Roasted Coffee) and organic chocolate brands (e.g., Dagoba, Green, and Black’s) use paper and the distinct color of cardboard boxes for outer packaging of their products. Similarly, content analysis of product packaging across four product categories in Austria, Denmark, Sweden, and Switzerland indicates that products positioned as organic are more likely to feature paper and less likely to feature plastic in their packaging (Chrysochou and Festila 2019). Second, media present consumers with messages consistent with the “paper ¼ good, plastic ¼ bad” belief. Plastic waste has received much negative media attention in recent years, with coverage of plastic pollution and plastic waste appearing in outlets such as The Guardian, The New York Times, and The Washington Post. Consumers receive news about national and municipal governments instituting plastic bag bans (Nielsen, Holmberg, and Stripple 2019) and plastic straw bans (Smith 2020), while allowing single-use paper bags and straws. People are also presented with visceral images of animals dying from plastic waste in documentaries like Planet Blue II (Dunn, Mills, and Ver ıssimo 2020). In sum, we propose that repeated sensory experiences, naturalness/unnaturalness beliefs, combined with unequal weighing of environmental impact from production versus disposal, and interactions with companies and mass media foster the “paper ¼ good, plastic ¼ bad” belief in consumers’ minds.

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A: Study 1a: product packaging and PEF (N ¼ 205, Mage ¼ 21.04, 64% female, Lab) Plastic þ paper condition

Plastic condition PEF score (a ¼ 0.89) Study design Main ﬁnding

2.67 (1.30) 1.87 (0.90)a Two-cell between-subjects design; participants rated a granola bar packaging on the four-item PEF scale Plastic þ paper packaging is perceived as more environmentally friendly than plastic-only packaging. B: Study 1b: visible versus hidden plastic (N ¼ 301, Mage ¼ 44.60, 42% female, MTurk) Visible plastic þ paper condition

Plastic condition

2.23 (1.36) 3.36 (1.58) 2.69 (1.40) Three-cell between-subjects design; participants rated a chocolate bar packaging on the PEF scale. Plastic þ paper packaging is perceived as more environmentally friendly than plastic-only packaging even when plastic is initially hidden under paper and revealed later as a surprise. C: Study 2a: PEF bias and proportion of paper (N ¼ 801, Mage ¼ 41.37, 51% female, MTurk) Plastic condition

PEF score (a ¼ 0.93) Study design Main ﬁnding

Plastic þ paper 1:0.5 proportion condition

Plastic þ paper 1:1 proportion condition

Plastic þ paper 1:2 proportion condition

2.16 (1.14) 2.91 (1.20) 3.06 (1.34) Four-cell between-subjects design; participants rated tomato packaging on the PEF scale. PEF bias is stronger when the paper-to-plastic proportion in packaging is large.

3.34 (1.48)

D: Study 2b: PEF bias and paper–plastic beliefs (N ¼ 602, Mage ¼ 35.13, 54% female, ProlificCo) Plastic condition

Plastic þ paper condition

PEF score (a ¼ 0.95) 3.28 (1.44) 4.37 (1.49) PEF score: participants with strong “paper 3.01 4.42 ¼ good, plastic ¼ bad” beliefs (þ1 SD) PEF score: participants with weak “paper 3.51 4.30 ¼ good, plastic ¼ bad” beliefs ( 1 SD) Study design Packaging type was manipulated between subjects, “paper ¼ good, plastic ¼ bad” beliefs were measured on multi-item scales, and participants rated honeycomb packaging on the PEF scale. Main ﬁnding PEF bias is stronger among people with stronger “paper ¼ good, plastic ¼ bad” beliefs (packaging type and beliefs interaction: F(1, 598) ¼ 6.73, p ¼ .010). E: Study 3: implications for willingness to pay (N ¼ 802, Mage ¼ 41.16, 54% female, ProlificCo) Plastic condition

Plastic þ paper condition

PEF score (a ¼ 0.95) 2.77 (1.47) 3.81 (1.42) WTP $0.94 (0.48) $1.09 (0.53) Indirect effect of packaging type on WTP via PEF: b ¼ 0.05, SE ¼ 0.01, 95% CI: (0.02; 0.08) Study design Two-cell between-subjects design; participants reported WTP for a granola bar. Next, on a separate screen, they rated the granola packaging on the PEF scale. Main ﬁnding Addition of paper to plastic in granola packaging increased WTP by 16% and increased packaging PEF scores. The effect of packaging type on WTP was partially driven by PEF. F: Study 4a: implications for choice (N ¼ 400, Mage ¼ 34.80, 67% female, ProlificCo) Plastic condition

Plastic þ paper condition

PEF score (a ¼ 0.96) 2.37 (1.40) 2.82 (1.57) Packaging utility 37.54 (67.07) 15.38 (46.57) Indirect effect of packaging type on packaging utility via PEF: b ¼ 3.81, SE ¼ 1.47, 95% CI: (1.42; 7.36) Study design Two-cell between-subjects design. In a choice-based conjoint experiment, participants made 12 choices between chocolate bars that varied in their packaging, price, and ﬂavor. For half the participants, the bars were either packaged in paper or in plastic. For the remaining participants, the bars were either packaged in paper or in plastic þ paper. We estimated the utilities of plastic (plastic þ paper) packaging from individual choices. At the end of the study, participants rated the plastic (plastic þ paper) chocolate packaging on the PEF scale. Main ﬁnding Addition of a layer of paper to plastic packaging made people more likely to select a chocolate over a chocolate packaged in paper. This effect was partially driven by PEF. (continued)

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PEF score (a ¼ 0.95) Study design Main ﬁnding

Hidden plastic þ paper condition

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JOURNAL OF CONSUMER RESEARCH TABLE 2 (CONTINUED) G: Study 4b: implications for choice of existing brands (N ¼ 402, Mage ¼ 35.67, 60% female, ProlificCo) Plastic þ paper condition

Plastic condition

H: Study 5: on-package intervention (N ¼ 590, Mage ¼ 19.93, 51% female, Lab) Plastic-control condition

Plastic-sticker condition

PEF score (a ¼ 0.95) 3.08 (1.47) 4.58 (1.47) Plastic packaging utility 10.98 (43.49) 35.05 (61.48) Indirect effect of packaging type on packaging utility via PEF: b ¼ 9.89, SE ¼ 2.58, 95% CI: (5.14; 15.22) Study design Two-cell between-subjects design; participants made 12 choices between granola bars that varied in their packaging, price, and ﬂavor. Half the participants chose between bars packaged in plastic or in plastic þ paper. The remaining participants chose between bars packaged in plastic with a “minimal packaging” sticker or in plastic þ paper. We estimated the utilities of plastic packaging from individual choices. At the end of the study, participants rated the plastic (control vs. sticker) packaging on the PEF scale. Main ﬁnding In the control condition, people were less likely to choose plastic-only packaged granola bars. By contrast, they were more likely to choose plastic-only packaged bars in the “minimal packaging” sticker intervention condition. This effect was partially driven by changes in the PEF of plastic packaging. a

We report standard deviations of group means in parentheses.

demonstrates that the effect is stronger among people with stronger “paper ¼ good, plastic ¼ bad” beliefs. Studies 3– 5 establish the downstream consequences of the PEF bias. Study 3 shows that consumers are willing to pay more for plastic-plus-paper-packaged products and this effect is driven by changes in PEF. Choice-based conjoint studies 4a and 4b demonstrate the implications of the PEF bias for consumer choice for hypothetical and real brands. Finally, choice-based conjoint study 5 shows that adding a “minimal packaging” sticker to plastic packaging attenuates the PEF bias and makes consumers more likely to choose plastic-packaged products over plastic-plus-paper (hereafter, plastic þ paper)-packaged products. The study stimuli, anonymized data, and syntax files are available at https://researchbox.org/712.

STUDY 1A: PRODUCT PACKAGING AND PERCEIVED ENVIRONMENTAL FRIENDLINESS Study 1a tests the effect of product packaging type— plastic versus plastic with an added layer of paper—in a laboratory setting using a real product—a granola bar.

Method Two hundred five students at a public university completed the study (Mage ¼ 21.04, 64% female). They were randomly assigned to one of two conditions in a two-cell (packaging type: plastic vs. plastic þ paper) betweensubjects design. Participants, sitting in individual cubicles, saw a real product—a granola bar—packaged either in plastic or in plastic þ paper (table 3). They were asked to rate the environmental friendliness of the granola bar packaging on a four-item 7-point scale (e.g., “This packaging is friendly to the environment”; 1 ¼ strongly disagree; 7 ¼ strongly agree; table 4) adapted from Gershoff and Frels (2015) and Haws, Winterich, and Naylor (2014). After rating the environmental friendliness of product packaging, participants completed the manipulation checks (see web appendix B for details). Finally, they reported their age and gender.

Results The four PEF scale items (a ¼ 0.89) were averaged to compute a PEF score. A one-way ANOVA showed that perceived environmental friendliness was lower in the “plastic” condition than in the “plastic þ paper” condition

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PEF score (a ¼ 0.96) 2.72 (1.35) 4.44 (1.52) Montperal brand utility 47.33 (83.06) 29.51 (86.45) Indirect effect of packaging type on packaging utility via PEF: b ¼ 10.54, SE ¼ 5.71, 90% CI: (1.50; 20.33) Study design Two-cell between-subjects design; participants made 12 choices among chips packs that varied in their brand, price, and weight. Half the participants chose between Lays, Tyrrells, and Montperal, all packaged in plastic. The remaining participants chose between the same brands, but the focal Montperal brand was packaged in plastic þ paper. We estimated the utilities of the Montperal brand from individual choices. At the end of the study, participants rated the plastic (plastic þ paper) Montperal packaging on the PEF scale. Main Finding Addition of a layer of paper to plastic packaging made people more likely to select the Montperal brand over the other brands. This effect was partially driven by PEF.

€ SOKOLOVA, KRISHNA, AND DORING TABLE 3 STUDY 1A: PACKAGING STIMULI

Plastic condition

Plastic+paper condition

475

the four-item PEF scale. Critically, participants in the “plastic” and “visible plastic þ paper” conditions saw the same image on the first and second pages. Participants in the “hidden plastic þ paper” condition saw the chocolate packaged in paper on the first page and then saw the chocolate packaged in plastic þ paper on the second page. They also read that they “<found> the chocolate to be covered in a second layer made of translucent plastic wrap.” Finally, participants reported their age and gender.

Results PERCEIVED ENVIRONMENTAL FRIENDLINESS (PEF) SCALE Item 1 Item 2 Item 3 Item 4

This packaging is friendly to the environment. The manufacturing and disposal of this packaging causes less harm to the environment. This packaging is relatively more eco-friendly than other packaging. This packaging deserves to be labeled “environmentally friendly.”

(Mplastic ¼ 1.87, SD ¼ 0.90, vs. Mplasticþpaper ¼ 2.67, SD ¼ 1.30, F(1, 203) ¼ 25.69, p < .001, gp2 ¼ 0.112).

Discussion Study 1a provides initial evidence of the PEF bias. It shows that adding a layer of paper to a layer of plastic increases the perceived environmental friendliness of product packaging.

STUDY 1B: VISIBLE VERSUS HIDDEN PLASTIC In study 1a, participants evaluated the environmental friendliness of packaging with both plastic and paper packaging visible at the same time. However, consumers often encounter products whose plastic packaging is fully covered by outer paper packaging (web appendix A), meaning that plastic packaging could be uncovered as a surprise after consumers purchase the product. Study 1b tests whether the PEF bias will emerge in these settings.

Method Three hundred one Amazon Mechanical Turk panelists (Mage ¼ 44.60, 42% female) were randomly assigned to one of three conditions in a three-cell (packaging type: plastic vs. visible plastic þ paper vs. hidden plastic þ paper) between-subjects design. On the first page, participants saw a picture of a packaged chocolate bar (top row in table 5). They then moved to a second page with the packaged chocolate image and

The four PEF scale items (a ¼ 0.95) were averaged to compute a PEF score. A one-way ANOVA revealed a significant effect of packaging type on the PEF scores (F(2, 298) ¼ 15.35, p < .001, gp2 ¼ 0.093). Follow-up contrasts showed that the PEF was significantly lower in the “plastic” condition than in the “visible plastic þ paper” condition (Mplastic ¼ 2.23, SD ¼ 1.36, vs. Mvisible plasitcþ 2 paper ¼ 3.36, SD ¼ 1.58, F(1, 298) ¼ 30.34, p < .001, gp ¼ 0.092) and the “hidden plastic þ paper” condition (Mplastic ¼ 2.23, SD ¼ 1.36, vs. Mhidden plasticþpaper ¼ 2.69, SD ¼ 1.40, F(1, 298) ¼ 5.11, p ¼ .025, gp2 ¼ 0.017). The PEF was also significantly lower in the “hidden plastic þ paper” condition than in the “visible plastic þ paper” condition (Mhidden plasticþpaper ¼ 2.69, SD ¼ 1.40, vs. Mvisible plasticþpaper ¼ 3.36, SD ¼ 1.58, F(1, 298) ¼ 10.66, p ¼ .001, gp2 ¼ 0.035).

Discussion Study 1b suggests that the PEF bias emerges when plastic is visible upfront or hidden under paper and discovered later as a surprise, attesting to the generalizability of our results. The next two studies probe two theoretically relevant boundary conditions of the PEF bias, to test for its underlying mechanism.

STUDY 2A: PEF BIAS AND PROPORTION OF PAPER Study 2a tests proportional reasoning as the underlying mechanism of the PEF bias. In this study, we manipulated the proportion of paper-to-plastic packaging by changing the size of paper packaging added to a layer of plastic, while keeping the size of plastic packaging constant. Per our theorizing, when the paper-to-plastic proportion in product packaging increases, the PEF should increase. By manipulating the size of paper packaging, study 2a also aimed to probe an alternative averaging account of the PEF bias (Chernev and Gal 2010). If paper is perceived as more environmentally friendly than plastic, averaging of the perceived environmental friendliness of plastic and paper packaging layers would lead to lower PEF evaluations for plastic than for plastic þ paper. Critically, when it

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TABLE 4

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JOURNAL OF CONSUMER RESEARCH TABLE 5 STUDY 1B: PACKAGING STIMULI

Visible plastic+paper condition

Hidden plastic+paper condition

Screen 2

comes to adding layers of paper of varying sizes, the averaging and the proportional reasoning accounts’ predictions diverge. A small-sized layer of paper should be perceived as more environmentally friendly than a large-sized layer of paper. Thus, per the averaging account, adding a smallsized layer of paper to plastic should lead to greater perceived environmental friendliness than adding a largesized layer of paper to plastic. By contrast, per the proportional reasoning account, adding a small-sized layer of paper to plastic should lead to lower perceived environmental friendliness than adding a large-sized layer of paper, because in the former case the paper-to-plastic proportion will be smaller. Study 2a tests these competing predictions.

Method Eight hundred two MTurk panelists completed this study. One participant was removed because of a duplicate IP, resulting in a final sample of 801 participants (Mage ¼ 41.37, 51% female).1 1

The results for this and the remaining studies with duplicate IP exclusions do not change if we include all completed surveys in the analysis. Web appendix C reports the result summaries with and without duplicate IP exclusions.

Participants were randomly assigned to one of four conditions (packaging type: plastic vs. plastic þ paper in three different proportions—1 plastic þ 1=2 paper, 1 plastic þ 1 paper, 1 plastic þ 2 paper). While the amount of plastic packaging remained the same across conditions, the amount of paper increased, and consequently, so did the proportion of paper in product packaging (table 6). Packaging layers were presented on the same screen, one above the other. The presentation order of plastic and paper layers (paper on top vs. plastic on top) was counterbalanced. Participants were asked to imagine that they bought tomatoes at a farmers’ market. They saw an image of tomatoes and an image of their packaging side by side. Presenting the tomatoes next to their packaging allowed us to make the amount of plastic and paper used in product packaging clear for the participants. In line with the paperto-plastic proportion account, we expected that increasing the amount of added paper would increase the perceived environmental friendliness of product packaging. Participants saw the tomato packaging and evaluated it on the four-item PEF scale. Next, participants completed a manipulation check (web appendix B) and reported their age and gender.

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Screen 1

Plastic condition

€ SOKOLOVA, KRISHNA, AND DORING

477 TABLE 6 STUDY 2A: PACKAGING STIMULI

Plastic+paper in 1:0.5 proportion condition

Plastic+paper in 1:1 proportion condition

Plastic+paper in 1:2 proportion condition

Results

Discussion

A one-way ANOVA on participants’ PEF scores (a ¼ 0.93) revealed a significant main effect of packaging type on PEF (F(3, 797) ¼ 30.15, p < .001, g2p ¼ 0.102). Simple contrasts showed that plastic-only packaging was perceived as less environmentally friendly compared to each of the other three plastic þ paper packaging types (all ps < .001). Importantly, consistent with the proportional reasoning account, the effect of adding paper to plastic was weaker when the paper-to-plastic proportion was small (Mplastic ¼ 2.16, SD ¼ 1.14, vs. M1 plasticþ1=2 paper ¼ 2.91, SD ¼ 1.20, F(1, 797) ¼ 32.62, p < .001, g2p ¼ 0.039) than when it was medium (Mplastic ¼ 2.16, SD ¼ 1.14, vs. M1 plasticþ1 paper ¼ 3.06, SD ¼ 1.34, F(1, 797) ¼ 47.50, p < .001, g2p ¼ 0.056), or large (Mplastic ¼ 2.16, SD ¼ 1.14, vs. M1 plasticþ2 paper ¼ 3.34, SD ¼ 1.48, F(1, 797) ¼ 83.58, p ¼ .001, g2p ¼ 0.095). A separate regression on the subsample of the three “plastic þ paper” conditions with the paper-toplastic proportion as a continuous independent variable confirmed that as the proportion of paper in product packaging increased, the PEF scores increased (b ¼ 0.28, SE ¼ 0.09, t ¼ 3.26, p ¼ .001).

By demonstrating that the PEF bias is stronger (weaker) when the paper-to-plastic proportion in packaging is large (small), study 2a provides evidence for the proportional reasoning account of the PEF bias and against its averaging account. One may argue that it is the absolute, not the relative amount of paper in product packaging, that drives the PEF bias. That is, the more paper there is in product packaging, the greater its perceived environmental friendliness. Data from studies 1a to 2a are indeed consistent with both the proportional and absolute amount of paper accounts of the PEF bias. To probe the absolute amount of paper account, we ran a follow-up study, where we compared the effect of adding paper to plastic and the effect of adding paper to paper (study A, web appendix D). Under the absolute amount of paper account, packaging comprised of one layer of paper should have lower PEF compared to packaging comprised of two layers of paper. By contrast, under the proportional reasoning account, one-layer and twolayer paper packaging should have similar PEF, since in both these cases, the packaging is composed of 100% paper. The results were consistent with the proportional

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Plastic condition

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JOURNAL OF CONSUMER RESEARCH

reasoning account and ran counter to the absolute amount of paper account: when a layer of paper was added to plastic packaging, consumers perceived the packaging as more environmentally friendly. The addition of a layer of paper to paper packaging had no effect on its perceived environmental friendliness.

bad for the environment on two separate three-item 7-point scales (web appendix E). The order of scales capturing the beliefs related to plastic and paper was counterbalanced. Finally, participants reported their age and gender.

STUDY 2B: PEF BIAS AND PAPER– PLASTIC BELIEFS

To test our predictions, we ran an ANCOVA with packaging type, participants’ standardized explicit belief scores, and their two-way interaction as the independent variables and with the packaging PEF score (a ¼ 0.95) as the dependent variable. The explicit belief scores were computed as the difference between participants’ beliefs about the environmental harm of plastic (a ¼ 0.94, M ¼ 6.10, SD ¼ 1.10) and their beliefs about the environmental harm of paper (a ¼ 0.87, M ¼ 3.54, SD ¼ 1.33). Higher explicit belief scores indicated that participants perceived greater differences between the environmental harm of plastic and paper, hereafter referred to as higher “paper ¼ good, plastic ¼ bad” belief scores. The analysis revealed a main effect of packaging type (F(1, 598) ¼ 85.46, p < .001, gp2 ¼ 0.125) and a significant interaction between packaging type and explicit beliefs (F(1, 598) ¼ 6.73, p ¼ .010, gp2 ¼ 0.011). The main effect of explicit beliefs was not significant (F(1, 598) ¼ 2.51, p ¼ .114, gp2 ¼ 0.004). Follow-up contrasts revealed that at the mean value of explicit beliefs, plastic packaging was perceived as less environmentally friendly than plastic þ paper packaging (Mplastic ¼ 3.28, SD ¼ 1.44 vs. Mplasticþpaper ¼ 4.37, SD ¼ 1.49, F(1, 598) ¼ 85.46, p < .001, gp2 ¼ 0.125), replicating previous results. Importantly, this effect was stronger among participants with higher “paper ¼ good, plastic

Method Six hundred three ProlificCo panelists completed this study. One survey was removed because of a duplicate IP, resulting in a final sample of 602 participants (Mage ¼ 35.13, 54% female). Participants were randomly assigned to one of two conditions (packaging type: plastic vs. plastic þ paper). In the main task, participants saw a honeycomb packaged in plastic or in plastic þ paper (table 7) and rated the perceived environmental friendliness of the honeycomb packaging on the four-item PEF scale. Next, to capture participants’ beliefs about plastic and paper, we asked them to indicate to what extent they believed that plastic and paper were

TABLE 7 STUDY 2B: PACKAGING STIMULI

Plastic condition

Plastic+paper condition

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Study 2b tests the effect of consumers’ beliefs about the environmental impact of paper and plastic on the PEF bias. Our theorizing implies that consumers hold “paper ¼ good, plastic ¼ bad” beliefs. As a result of these beliefs, consumers judge plastic þ paper packaging as more environmentally friendly than plastic packaging. As such, we can expect that the PEF bias will be stronger among consumers with stronger “paper ¼ good, plastic ¼ bad” beliefs.

Results

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¼ bad” belief scores (þ1 SD; Mplastic ¼ 3.01 vs. Mplasticþpaper ¼ 4.42, F(1, 598) ¼ 69.71, p < .001, gp2 ¼ 0.104) than among participants with lower “paper ¼ good, plastic ¼ bad” belief scores ( 1 SD; Mplastic ¼ 3.51 vs. Mplasticþpaper ¼ 4.30, F(1, 598) ¼ 22.16, p < .001, gp2 ¼ 0.036). Floodlight analysis (Spiller et al. 2013) revealed that the Johnson-Neyman point at which packaging type has a significant effect on PEF scores at p ¼ .05 lies at Mbeliefs ¼ 1.92. In the sample, 99% of the explicit belief scores were above the Johnson-Neyman threshold of 1.92.

Discussion The study tested the effect of explicit beliefs about plastic and paper on the PEF bias. The results suggest that the PEF bias is stronger among participants who believe that the difference between the environmental harm of plastic and paper is relatively large and weaker among those who believe that the difference between the environmental harm of plastic and paper is smaller. Together, studies 1a–2b provide robust evidence of the PEF bias, attesting to its generalizability across different product categories and decision contexts. They also provide evidence of the underlying process of the PEF bias. The next four studies examine the downstream consequences of the PEF bias for consumer decision-making.

STUDY 3: IMPLICATIONS FOR WILLINGNESS TO PAY Study 3 examines the implications of the PEF bias for consumers’ willingness to pay.

Method Eight hundred five ProlificCo panelists completed the study. Three surveys were removed due to duplicate IPs,

Results Willingness to Pay. A one-way ANOVA indicated that participants were willing to pay less for the plasticpackaged granola bar compared to the plastic þ paperpackaged one (Mplastic ¼ $0.94, SD ¼ 0.48, vs. Mplasticþpaper ¼ $1.09, SD ¼ 0.53, F(1, 800) ¼ 18.12, p < .001, gp2 ¼ 0.022). Perceived Environmental Friendliness. Next, we analyzed participants’ PEF scores (a ¼ 0.95) across the two packaging type conditions. Replicating prior results, a oneway ANOVA revealed that people perceived plastic packaging to be less environmentally friendly than plastic þ paper packaging (Mplastic ¼ 2.77, SD ¼ 1.47, vs. Mplasticþpaper ¼ 3.81, SD ¼ 1.42, F(1, 800) ¼ 103.84, p < .001, gp2 ¼ 0.115). Mediation Analysis. A mediation analysis with 10,000 bootstrap samples revealed a significant indirect effect of packaging type on willingness to pay via PEF [b ¼ 0.05, SE ¼ 0.01, 95% CI: (0.02; 0.08); figure 1], suggesting that packaging type affected participants’ willingness to pay for the granola bar by affecting the environmental friendliness perceptions of the bar’s packaging.

TABLE 8 STUDY 3: PACKAGING STIMULI

Plastic condition

Plastic+paper condition

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resulting in a final sample of 802 participants (Mage ¼ 41.16, 54% female). Participants were randomly assigned to one of two conditions (packaging type: plastic vs. plastic þ paper). In the main task, participants saw a granola bar packaged either in plastic or in plastic þ paper (table 8) and indicated how much they would be willing to pay for the bar on an unmarked slider scale anchored on $0 on the left and on $4 on the right. Next, on a separate screen, participants rated the perceived environmental friendliness of the granola packaging on the four-item PEF scale. Finally, participants reported their age and gender.

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JOURNAL OF CONSUMER RESEARCH FIGURE 1 STUDY 3: PERCEIVED ENVIRONMENTAL FRIENDLINESS OF PACKAGING MEDIATES THE EFFECT OF PACKAGING TYPE ON WILLINGNESS TO PAY

a*** b = 1.04 (0.10)

b*** b = 0.04 (0.01)

c*** b = 0.15 (0.04) c’ ** b = 0.11 (0.04)

Willingness to pay

ab path: b = 0.05, SE = 0.01, CI 95%: (0.02; 0.08)

Coefficient standard errors are marked in parentheses. * p < .05, ** p < .01, *** p < .001

Discussion

While consumers may feel that they should pay more for products with additional packaging, they may be less likely to choose these products. Thus, study 4a tests the effect of packaging type on choice, using a choice-based conjoint experiment.

to one of two conditions (packaging type: plastic vs. plastic þ paper). At the beginning of the study, participants read that they would be making a series of choices between chocolate bars. The bars were described on three attributes—price ($3.00 vs. $3.50 vs. $4.00), packaging (“paper vs. plastic” vs. “paper vs. plastic þ paper”), and flavor (dark chocolate vs. dark chocolate with strawberries). To rule out the possibility that our packaging manipulation led to additional interferences about product quality, participants were also explicitly informed that the evaluated chocolate bars varied only on price, packaging, and flavor. Participants then made 12 choices between pairs of chocolate bars. The choice sets were created in Sawtooth software using the balanced overlap method (see table 9 for screenshots of sample choice tasks). In the “plastic” condition, the choice pairs included two types of packaging—paper (only) and plastic (only). In the “plastic þ paper” condition, the choice pairs also included two types of packaging—paper (only) and plastic þ paper. The inclusion of paper packaging in both conditions allowed us to compare participants’ choice propensities for plastic packaging relative to plastic þ paper packaging in a between-subjects setting. After making 12 choices between pairs of chocolate bars, participants in the “plastic” (“plastic þ paper”) condition saw a chocolate bar packaged in plastic (plastic þ paper) and rated the environmental friendliness of its packaging on the four-item PEF scale. Finally, they reported their age and gender.

Method

Results

Four hundred ProlificCo panelists completed the study (Mage ¼ 34.80, 67% female). They were randomly assigned

Conjoint Analysis. We obtained individual-specific utilities of each attribute—price, packaging, flavor—using

This study provides further evidence of the PEF bias in packaging evaluations and demonstrates its implications for consumers’ willingness to pay. We observe that addition of a layer of paper to plastic packaging increased consumers’ willingness to pay by 15 cents, or by 16%, a difference by no means trivial for the fast-moving consumer goods sector. We also observe that the effect of packaging type on WTP was mediated by packaging environmental friendliness perceptions. However, packaging type may have affected willingness to pay via multiple mechanisms, for example, by changing the inferred product quality. Critically, if product quality is correlated with perceived environmental friendliness of packaging, study 3 would run the risk of overestimating the role of PEF in driving consumers’ willingness to pay. As such, in our next study, we aimed to minimize the possibility that packaging type prompted additional inferences about product quality. Moreover, we aimed to explore whether PEF has implications for product choice, and not just willingness to pay.

STUDY 4A: IMPLICATIONS FOR CHOICE

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Packaging type (0 = plastic; 1 = plastic+paper)

Perceived environmental friendliness

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481 TABLE 9

STUDY 4A: SAMPLE CHOICE TASK IN THE TWO PACKAGING CONDITIONS

Plastic condition

the hierarchical Bayes procedure in Sawtooth separately for the “plastic” and “plastic þ paper” conditions (table 10). Packaging and flavor attributes were dummy coded with paper packaging and dark chocolate flavor serving as the baseline. Price was coded linearly ($3.00 ¼ 0; $3.50 ¼ 1; $4.00 ¼ 2). Next, we ran one-way ANOVAs to compare individual-specific attribute utilities across packaging conditions.

Table 10 shows that, as one would expect, price had a negative utility, suggesting that people were significantly more likely to choose low-priced compared to high-priced chocolate bars across conditions. There was no significant difference in the utility of price across the “plastic” and “plastic þ paper” conditions (F(1, 398) ¼ 0.02, p ¼ .901, gp2 < 0.001). Flavor had a negative utility, which was not significantly different from zero, suggesting that people

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Plastic+paper condition

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JOURNAL OF CONSUMER RESEARCH TABLE 10 STUDY 4A: ATTRIBUTE UTILITIESa Plastic þ paper condition

Plastic condition M (SD) Zero-centered utility scoresb Price Packagingc Flavor

56.11 (26.09) 37.54 (67.07) 8.42 (140.48)

t-Stat. (Test value ¼ 0)

p-Value

M (SD)

30.42 7.92 0.85

<.001 <.001 .398

55.75 (31.99) 15.38 (46.57) 21.39 (167.38)

t-Stat. (Test value ¼ 0)

p-Value

24.64 4.67 1.81

<.001 <.001 .072

were not more likely to choose the dark chocolate flavor over the dark chocolate with strawberries flavor. There was no significant difference in the utility of flavor across the two packaging conditions (F(1, 398) ¼ 0.71, p ¼ .402, gp2 ¼ 0.002). Next, we analyzed the utility of packaging across the “plastic” and “plastic þ paper” conditions. In the “plastic” condition, the average utility of plastic packaging was negative and significantly different from zero, suggesting that, on average, people were more likely to choose chocolate in paper packaging compared to chocolate in plastic packaging (Mplastic ¼ 37.54, SD ¼ 67.07, t (199) ¼ 7.92, p < .001). Similarly, in the “plastic þ paper” condition, the average utility of plastic þ paper packaging was negative and significantly different from zero, suggesting that people on average were more likely to choose chocolate in paper than chocolate in plastic þ paper packaging (Mplasticþpaper ¼ 15.38, SD ¼ 46.57, t (199) ¼ 4.67, p < .001). Importantly, plastic packaging had a greater disutility compared to plastic þ paper packaging (F(1, 398) ¼ 14.72, p < .001, gp2 ¼ 0.036), meaning that participants’ propensity to choose chocolate in plastic packaging was lower than their propensity to choose chocolate in plastic þ paper packaging. Perceived Environmental Friendliness. Next, we analyzed participants’ PEF scores (a ¼ 0.96) of plastic (plastic þ paper) packaging. A one-way ANOVA revealed that people perceived plastic packaging to be less environmentally friendly than plastic þ paper packaging (Mplastic ¼ 2.37, SD ¼ 1.40, vs. Mplasticþpaper ¼ 2.82, SD ¼ 1.57, F(1, 398) ¼ 9.29, p ¼ .002, gp2 ¼ 0.023). Mediation Analysis. For mediation analysis, we used our estimated individual-specific utilities as the dependent variable and participants’ PEF scores as the mediator. Mediation with 10,000 bootstrap samples revealed that packaging type had a significant indirect effect on packaging utilities via PEF [b ¼ 3.81, SE ¼ 1.47, 95% CI: (1.42; 7.36); see web appendix G for a full summary of mediation

results for studies 4a–5]. Thus, consumers were more likely to choose chocolate in plastic þ paper (vs. plastic) packaging, because they viewed plastic þ paper packaging as more environmentally friendly than plastic-only packaging.

Discussion This study replicates the effect of packaging type on the environmental friendliness perceptions and demonstrates the implications of this effect for consumers’ choice. In this study, we used a choice-based conjoint setup to compare the impact of product packaging on product choice. We observed that addition of a layer of paper to plastic packaging made people more likely to select a chocolate over a chocolate packaged in paper. In addition, this study addresses the possible limitation of study 3 wherein consumers could have made additional inferences about product quality across the two packaging conditions. In this study, we informed consumers upfront that the evaluated products only differed in terms of their price, flavor, and packaging to minimize possible inferences regarding product quality. As our effect was replicated, we would suggest that our results are not likely driven by quality inferences.

STUDY 4B: IMPLICATIONS FOR CHOICE OF EXISTING BRANDS Study 4a showed that consumers are less prone to choose a chocolate bar packaged in plastic than to choose a chocolate bar packaged in plastic þ paper. It also demonstrated that this effect is mediated by PEF. One possible limitation of study 4a is that the two chocolate bar images only varied in terms of their packaging. While this manipulation allowed us to control for possible confounding effects of brand name and minimized possible additional inferences regarding product quality, it may have prompted our participants to pay more attention to product packaging than

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a As a robustness check, we also estimated attribute utilities across packaging conditions using an aggregate logit approach for this study and the remaining choice-based conjoint studies 4b and 5. The effect of packaging type on packaging utility was replicated. The results of the analysis are reported in web appendix F. Since logit estimation does not produce individual-level utility estimates, we could not test mediation through PEF scores with the logit approach. b $3.00 price, paper packaging, and dark chocolate ﬂavor served as the baseline attribute levels for utility estimates. c On average, plastic is 37.54 utils worse than paper, whereas plastic þ paper is 15.38 utils worse than paper. As such, plastic is 22.16 utils worse than plastic þ paper.

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Method Four hundred two ProlificCo panelists (Mage ¼ 35.67, 60% female) were randomly assigned to one of two conditions (packaging type: plastic vs. plastic þ paper). The method was similar to that used in study 4a. Participants in the “plastic” condition saw Lays, Tyrrells, and Montperal brands, all packaged in plastic. Participants in the “plastic þ paper” condition saw Lays and Tyrrells brands packaged in plastic and the Montperal brand packaged in plastic þ paper (see table 11 for screenshots of sample choice tasks). In addition to brand, the chips bags varied in terms of price ($2.00, $3.00, $4.00) and weight (3 oz, 5 oz). Participants made 12 choices among three bags of chips. Then, they saw the Montperal chips and rated the environmental friendliness of their plastic (plastic þ paper) packaging on the four-item PEF scale. Finally, they reported their age and gender.

Results Conjoint Analysis. We obtained individual-specific utilities of each attribute—price, brand, and weight—using the hierarchical Bayes procedure in Sawtooth separately

for the “plastic” and the “plastic þ paper” conditions (table 12). Because our focus was on the changes in the relative choice propensities of Montperal over the other brands, brand attribute was dummy coded, such that the Montperal brand was coded as 1 and the other two brands were coded as 0. Weight was dummy coded (3 oz ¼ 0, 5 oz ¼ 1). Price was coded linearly ($2.00 ¼ 0; $3.00 ¼ 1; $4.00 ¼ 2). Next, we ran one-way ANOVAs to compare attribute utilities across packaging conditions. As expected, the analysis revealed that price had a significant negative utility, whereas weight had a significant positive utility (table 12). There was no significant difference in the utility of price or of weight across the “plastic” and “plastic þ paper” conditions (Fprice(1,400) ¼ 0.85, p ¼ .356, gp2 ¼ 0.002; Fweight(1,400) ¼ 1.57, p ¼ .211, gp2 ¼ 0.004). Next, we analyzed the utility of brand across the two packaging conditions. In the “plastic” condition, the average utility of the Montperal brand was negative and significantly different from zero, suggesting that people on average were less prone to choose it over Lays and Tyrrells (Mplastic ¼ 47.33, SD ¼ 83.06, t (200) ¼ 8.08, p < .001). In the “plastic þ paper” condition, the average utility of the Montperal brand was also negative and significantly different from zero (Mplasticþpaper ¼ 29.51, SD ¼ 86.45, t (200) ¼ 4.84, p < .001). Importantly, there was a significant difference in brand utilities across the two packaging conditions (F(1, 400) ¼ 4.44, p ¼ .036, gp2 ¼ 0.011), suggesting that the disutility of the Montperal brand was greater when this brand came in plastic packaging than when it came in plastic þ paper packaging. Put differently, participants were less likely to choose Montperal brand over Lays and Tyrrells when it came in plastic packaging than when it came in plastic þ paper packaging. Perceived Environmental Friendliness. Next, we analyzed the PEF scores (a ¼ 0.96) of plastic (plastic þ paper) packaging. A one-way ANOVA revealed that people perceived plastic packaging to be less environmentally friendly than plastic þ paper packaging (Mplastic ¼ 2.72, SD ¼ 1.35, vs. Mplasticþpaper ¼ 4.44, SD ¼ 1.52; F(1, 400) ¼ 144.79, p < .001, gp2 ¼ 0.266). Mediation Analysis. Finally, a mediation analysis with 10,000 bootstrap samples revealed that packaging type had a marginally significant indirect effect on choice via PEF [b ¼ 10.54, SE ¼ 5.71, 90% CI: (1.50; 20.33)]. This result indicates that consumers were more likely to choose the Montperal brand when it came in plastic þ paper packaging than when it came in plastic packaging, in part, because they viewed the plastic þ paper packaging as more environmentally friendly than plastic packaging.

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they would have otherwise. To address this concern, study 4b used three real-life brands (Lays, Tyrrells, and Montperal). We then varied the Montperal packaging between-subjects, such that half the participants saw the Montperal brand in plastic packaging and half the participants saw it in plastic þ paper packaging. Critically, instead of informing the participants that the evaluated products varied in terms of price, packaging, and flavor, in this study, we informed them that the evaluated products varied in terms of price, brand, and weight. Thus, in contrast to study 4a, study 4b drew participants’ attention to differences across products in terms of brands, rather than in terms of packaging, to ensure greater ecological validity of our results. In addition, to ensure greater ecological validity, the study used two versions of Montperal packaging that are in fact marketed by the brand. While study 4a presented an “all else equal” comparison, where the only difference between plastic and plastic þ paper packaging was the added layer of paper, study 4b used plastic and plastic þ paper packaging that varied on more than one dimension but represented real packaging of the focal brand. As such, this manipulation allowed us to test how changes in product packaging that may be implemented by a real company affect consumer choice and environmental friendliness perceptions. As in study 4a, we expected that consumers’ propensity to choose the focal brand (i.e., Montperal) would be lower when it came in plastic-only packaging than when it came in plastic þ paper packaging.

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JOURNAL OF CONSUMER RESEARCH TABLE 11 STUDY 4B: SAMPLE CHOICE TASK IN THE TWO PACKAGING CONDITIONS

Plastic condition

Discussion Replicating study 4a results, study 4b shows that consumers become more prone to choose a product when it comes in plastic þ paper packaging compared to when it comes in plastic-only packaging. This study used real brands of chips and did not draw participants’ attention to variation in product packaging, ensuring greater ecological validity of our findings.

STUDY 5: ON-PACKAGE INTERVENTION Studies 4a and 4b used between-subjects conjoint experiments to demonstrate that people perceive plastic packaging as less environmentally friendly than plastic þ paper packaging. The studies also showed that differences in perceived environmental friendliness of plastic versus plastic þ paper translate into a relative disutility and lower

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Plastic+paper condition

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485 TABLE 12 STUDY 4B: ATTRIBUTE UTILITIES Plastic þ paper condition

Plastic condition M (SD) Zero-centered utility scoresa Price Montperal brandb Weight

68.98 (25.74) 47.33 (83.06) 84.13 (49.50)

t-Stat. (Test value ¼ 0)

p-Value

M (SD)

38.00 8.08 24.10

<.001 <.001 <.001

66.66 (24.60) 29.51 (86.45) 90.20 (47.55)

t-Stat. (Test value ¼ 0)

p-Value

38.42 4.84 26.89

<.001 <.001 <.001

$2.00 price, Lays and Tyrrells brands, and 3 oz weight served as the baseline attribute levels for utility estimates. On average, Montperal is 47.33 utils worse than the other two brands when it comes in plastic packaging; it is 29.51 utils worse when it comes in plastic þ paper packaging. b

Method Students at a public university (N ¼ 590, Mage ¼ 19.93, 51% female) were randomly assigned to one of two conditions (intervention: plastic control vs. plastic sticker). The method was similar to that adopted in studies 4a and 4b. Participants made 12 choices between two granola bars. Half the participants saw granola bars packaged in plastic þ paper or in plastic only (plastic-control condition). The remaining participants saw the bars packaged in plastic þ paper or in plastic with a sticker “USDA certified minimal packaging” (plastic-sticker condition; see table 13 for screenshots of sample choice tasks). In addition to packaging, the bars were described on price ($3.00 vs. $3.50 vs. $4.00) and flavor (chocolate chips vs. nuts). After making 12 choices between granola bars, participants saw the plastic-packaged granola bar (without or with a sticker) and rated its packaging on the four-item PEF scale. Finally, they reported their age and gender.

Results Conjoint Analysis. We obtained individual-specific utilities of each attribute—price, packaging, and flavor— using the hierarchical Bayes procedure in Sawtooth separately for the “plastic-control” and “plastic-sticker” conditions (table 14). Packaging and flavor attributes were dummy coded with plastic þ paper packaging and nuts flavor serving as the baseline. Price was coded linearly ($3.00 ¼ 0; $3.50 ¼ 1; $4.00 ¼ 2). We then ran one-way

ANOVAs to compare attribute utilities across the “plasticcontrol” and “plastic-sticker” conditions. The analysis revealed that price had a significant negative utility, and the disutility of price was greater in the “plastic-control” condition (Mplastic-control ¼ 62.74, SD ¼ 28.33, vs. Mplastic-sticker ¼ 56.87, SD ¼ 27.46, F(1, 588) ¼ 6.54, p ¼ .011, gp2 ¼ 0.011). Flavor had a significant positive utility, meaning that chocolate chips were preferred, on average, to nuts. There was no significant difference in the utility of flavor across the “plastic-control” and “plastic-sticker” conditions (F(1, 588) ¼ 0.57, p ¼ .449, gp2 ¼ 0.001). Next, we analyzed the effect of the sticker intervention on the utility of packaging. In the “plastic-control” condition, the average utility of plastic packaging was negative and significantly different from zero (Mplastic-control ¼ 10.98, SD ¼ 43.49, t (294) ¼ 4.33, p < .001), suggesting that, on average, people were less prone to choose the bar in plastic than the bar in plastic þ paper. Thus, the lower choice propensity for plastic compared to plastic þ paper packaging, observed in the between-subjects studies 4a and 4b, manifested in a within-subjects design as well. Critically, in the “plastic-sticker” condition, the utility of plastic became positive and significantly different from zero (Mplastic-sticker ¼ 35.05; SD ¼ 61.48, t (294) ¼ 9.79, p < .001), suggesting that when the sticker intervention was introduced, on average, people were more prone to select the product in plastic packaging over the product in plastic þ paper packaging. Thus, with the sticker intervention, there was a reversal in preference for plastic over plastic þ paper. Finally, the difference in packaging utilities was significant across the two intervention conditions (F(1, 588) ¼ 110.22, p < .001, gp2 ¼ 0.158), suggesting that the bar in plastic packaging was significantly less likely to be chosen in the “plastic-control” condition compared to the “plasticsticker” condition. Perceived Environmental Friendliness. Next, we analyzed the PEF scores (a ¼ 0.95) of plastic packaging across the “plastic-control” and “plastic-sticker” conditions. A

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choice propensity for products packaged in plastic compared to products packaged in plastic þ paper. Study 5 introduces a managerially relevant intervention that aims to alleviate this bias in environmental friendliness perceptions, making consumers value plastic packaging more than plastic þ paper packaging. In addition, the study tests whether, holding everything else equal, we will also observe the relative advantage of plastic þ paper packaging when people choose between plastic- and plastic þ paper-packaged products.

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JOURNAL OF CONSUMER RESEARCH TABLE 13 STUDY 5: SAMPLE CHOICE TASK IN THE TWO INTERVENTION CONDITIONS

Plastic-control condition

one-way ANOVA revealed that people perceived plastic packaging to be less environmentally friendly in the “plastic-control” condition than in the “plastic-sticker” condition (Mplastic-control ¼ 3.08, SD ¼ 1.47, vs. Mplasticsticker ¼ 4.58, SD ¼ 1.47, F(1, 588) ¼ 152.10, p < .001, gp2 ¼ 0.206). Mediation Analysis. A mediation analysis with 10,000 bootstrap samples showed that packaging intervention had a significant indirect effect on choice via PEF [b ¼ 9.89,

SE ¼ 2.58, 95% CI: (5.14; 15.22)]. This result indicates that our “minimal packaging sticker” intervention affected the choice propensities for plastic packaging by making consumers view plastic packaging as more environmentally friendly.

Discussion Study 5 introduced a managerially relevant on-package intervention to attenuate the PEF bias. The results show

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Plastic-sticker condition

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487 TABLE 14 STUDY 5: ATTRIBUTE UTILITIES Plastic-control condition

M (SD) Zero-centered utility scoresa Price (Plastic) packagingb Flavor

62.74 (28.33) 10.98 (43.49) 118.47 (99.43)

Plastic-sticker condition

t-Stat. (Test value ¼ 0)

p-Value

M (SD)

38.04 4.33 20.46

<.001 <.001 <.001

56.87 (27.46) 35.05 (61.48) 112.45 (93.36)

t-Stat. (Test value ¼ 0)

p-Value

35.57 9.79 20.69

<.001 <.001 <.001

$3.00 price, plastic þ paper packaging, and nuts ﬂavor served as the baseline attribute levels for utility estimates. On average, plastic is worse than plastic þ paper packaging by 10.98 utils in the plastic-control condition. Plastic is better than plastic þ paper packaging by 35.05 utils in the plastic-sticker condition. a b

GENERAL DISCUSSION Across eight studies, we show that objectively less environmentally friendly plastic þ paper packaging is systematically perceived as more environmentally friendly compared to plastic-only packaging. We refer to this effect as the PEF bias in packaging evaluations. Studies 1a and 1b provide evidence of the PEF bias and show that the effect manifests in lab and online settings when plastic is visible upfront or revealed later.2 Next, studies 2a and 2b test two theoretically relevant boundary conditions of the PEF bias. Study 2a shows that the effect is stronger when the proportion of paper in product packaging increases; and study 2b shows that the effect is stronger among people with stronger “paper ¼ good, plastic ¼ bad” beliefs. Studies 3–4b establish the downstream consequences of the PEF bias for consumer willingness to pay (study 3) and choice (studies 4a and 4b). Study 5 introduces a managerially relevant intervention, wherein addition of a “minimal packaging” sticker to plastic packaging increases the environmental friendliness perceptions of plastic-only 2

Studies B and C (web appendices H and I) further attest to the generalizability of the PEF bias and show that the bias emerges for both food and non-food categories and that it holds in stimulus- and memory-based evaluations. Only when additional paper packaging is conspicuously superfluous (e.g., when paper packaging is four times larger than the product), do we find that consumers perceive plasticonly packaging as more environmentally friendly than the plastic þ paper option (study D, web appendix J).

packaging, making people more likely to choose plasticpackaged products over their plastic-plus-paper overpackaged counterparts. To assess the evidential value of the studies reported in the paper, we used the p-curve method (Simonsohn, Nelson, and Simmons 2014). To conduct the p-curve analysis, we used the seven studies for which the PEF scores for both the “plastic” and “plastic þ paper” conditions were available (web appendix K). The analysis indicated that the reported studies have evidential value, with the power of tests included in the p-curve estimated at 99%, after correcting for selective reporting.

Theoretical Implications Product Packaging and Consumer Decisions. Our research contributes to the packaging literature in marketing. Extant research has examined several dimensions of product packaging design, attesting to its important role in consumer judgments and decisions. For instance, packaging size (e.g., small vs. large; single serve vs. multi-serve) is known to affect consumers’ perceptions of product efficacy (Ilyuk and Block 2016) and consumption amounts (Argo and White 2012; Coelho do Vale et al. 2008). Graphic design of product packaging (e.g., pale vs. bright coloring; high vs. low image placement) has been shown to influence consumers’ purchase intentions and willingness to pay (Mai et al. 2016; Sundar and Noseworthy 2014). Finally, the presence of on-package labeling (e.g., low-fat; Nutri-score food labels) is suggested to affect products’ purchase and consumption rates (Dubois et al. 2021; Wansink and Chandon 2006). We add to the above line of work by examining how packaging composition—plastic versus plastic þ paper—shifts consumers’ packaging evaluations and how these evaluations affect product valuation and purchase decisions. Sustainable Consumer Behavior. This research also contributes to the growing stream of literature in marketing and sustainability by revealing perceptual barriers to sustainable consumption. Extant research highlights the challenge to increase sustainable consumer behavior (White

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that addition of a “minimal packaging” sticker not only attenuates but also reverses the effect of adding paper to plastic packaging on choice. In the “plastic-control” condition, plastic packaging had a negative utility compared to the plastic þ paper baseline, meaning that people were less likely to choose plastic-packaged granola bars than plastic þ paper-packaged granola bars. Importantly, in the “plastic-sticker” condition, plastic had a positive utility, meaning that people became more prone to choose plasticpackaged granola bars than plastic þ paper-packaged granola bars.

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Alternative Accounts of the Perceived Environmental Friendliness Bias While our studies provide evidence of the underlying mechanism of the PEF bias and probe several alternative explanations, there are at least three additional plausible alternative accounts of our results. Packaging Quality Inferences. One may argue that the addition of paper packaging to plastic packaging prompts inferences about the quality of plastic used in the “plastic þ paper” condition. For example, one may assume that products in plastic þ paper packaging are wrapped in thinner layers of plastic compared to products packaged in plastic alone. Alternatively, people may infer that the product manufacturer is generally more committed to use ecofriendly packaging materials in the “plastic þ paper” condition. As a result, they may assume that the plastic used in the “plastic þ paper” condition is more environmentally friendly than that used in the “plastic” condition. To probe this additional alternative account, we ran a follow-up study (study D, web appendix J). In this study, we measured the perceived environmental friendliness of product packaging (plastic vs. plastic þ paper). Then, on a separate screen, we reminded the participants that the product in the preceding task used plastic packaging and asked them to estimate the number of months it would take that plastic packaging to disintegrate in a landfill. The analysis did not reveal significant differences across the “plastic” and “plastic þ paper” conditions in terms of disintegration time for the plastic. As such, even though it is possible that additional paper packaging sometimes makes plastic packaging seem more environmentally friendly, we do not think that this process can account for the PEF bias. Changes in (Inferred) Objective Environmental Friendliness. One may also argue that additional paper packaging increases perceived environmental friendliness not because consumers fail to factor in the increased amount of packaging in their PEF evaluations, but because they think that the additional packaging increases the

objective environmental friendliness of packaging overall. For example, one could think that plastic þ paper packaging is objectively more environmentally friendly because it preserves the packaged products better and, thus, reduces possible waste. To probe this account, we ran a follow-up study where three groups of participants rated granola bar packaging from study 1a (study E, web appendix L). One group rated plastic packaging, and one group rated plastic þ paper packaging. Critically, a third group rated both the plastic and plastic þ paper packaging, with the two packaging types presented on the same screen in a random order. We replicated the PEF bias in the between-subjects evaluation. In the within-subjects evaluation, where people saw and evaluated plastic and plastic þ paper packaging side by side on the same screen, the PEF of the two packaging types was not significantly different. Had the effect of product type been driven by preservation-related concerns or by other beliefs about objectively greater environmental friendliness of packaging with additional layers of paper, we would expect the effect of packaging type to emerge in within-subjects evaluations. This, however, was not the case. Counterfactual Thinking. Finally, one could argue that the PEF bias emerges because plastic and plastic þ paper packaging types evoke different counterfactual thoughts. When seeing plastic packaging, people may think that the alternative to packaging a product in a layer of plastic is packaging it in a layer of paper. By contrast, when seeing plastic þ paper packaging, people may be more prone to consider the alternative where the product is packaged in two layers of plastic. This means that in our studies, in the “plastic” condition, the participants may have been comparing the focal packaging to a subjectively environmentally friendly “paper” alternative. In the “plastic þ paper” condition, the participants may have been comparing the focal packaging to a subjectively environmentally harmful “plastic þ plastic” alternative. As a result of this difference in the evoked comparison standards, plastic packaging would be perceived as less environmentally friendly than plastic þ paper packaging. While counterfactual thinking could have affected the results in studies 1a–3, where participants evaluated a given packaging in isolation, we think it is less likely to have affected our results in studies 4a and 4b. For example, in study 4a, the participants were making choices between chocolate bars packaged in paper or plastic in the “plastic” condition and between bars packaged in paper or plastic þ paper in the “plastic þ paper” condition. After that, the participants rated the environmental friendliness of plastic or of plastic þ paper packaging. We think that participants in both the “plastic” and “plastic þ paper” conditions were likely to use paper packaging as a comparison standard for their PEF evaluation, because this was the packaging they saw alongside the focal plastic (plastic þ paper) packaging

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et al. 2019). While consumer inaction is one of the barriers to sustainable behavior, we show that consumers’ systematically biased perceptions of environmental friendliness can also mitigate pro-environmental outcomes. We find that environmental friendliness judgments of packaging are based on “paper ¼ good, plastic ¼ bad” beliefs. We further demonstrate that these beliefs can bias environmental friendliness judgments and influence consumers’ willingness to pay and choice. As such, in addition to shedding light onto processing of environmental information in the marketplace, our research underscores the importance of studying differences between consumer perceptions of environmental friendliness and objective reality.

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Practical Implications From a managerial perspective, our research provides important insights for companies aiming to boost the perceived environmental friendliness of their products. In their responses to a 2022 Deloitte consumer survey on sustainability beliefs, over half the respondents said they would consider a product sustainable if it used minimal or recyclable packaging (Deloitte 2022). Our results reveal a different pattern: we find that overpackaged products can be perceived as more sustainable compared to minimally packaged ones when excessive packaging is made of paper. We show that that additional paper packaging increases perceived environmental friendliness across multiple contexts: for food and non-food products, when both paper and plastic are visible and when plastic is initially hidden and revealed later. As such, our results alert companies to the potential disparities between consumers’ self-reported attitudes to overpackaging in general and their evaluations and choices of specific overpackaged products. Relatedly, our findings are of relevance for companies working to increase the objective environmental friendliness of their products by reducing overpackaging. As noted earlier, companies such as Kiehl’s and Nestle already eliminate unnecessary paper packaging in some of their products. Other examples include Amazon that recently required its vendors to make their paper box packaging more compact and environmentally friendly (Gasparro 2019) and British supermarket chain Tesco, which launched a trial to eliminate needless toothpaste packaging for private label and national brands (Tesco 2022). These initiatives can curtail the environmental harm from singleuse paper production and disposal and reduce the ecological footprint from product transportation. Yet, our research suggests that these initiatives need to come in conjunction with front-of-pack labeling to boost consumers’ environmental friendliness perceptions and choice. More generally, companies should not assume that consumers will readily incorporate reduced amounts of packaging into

their judgments. Rather, consumers need additional communications about companies’ minimal packaging initiatives to make more sustainable product choices. Next, our results have implications for companies aiming to boost the objective environmental friendliness of their packaging by eliminating plastic packaging and switching to paper-only packaging. Our choice-based conjoint study 4a shows that when consumers choose between an ostensibly more environmentally friendly paperpackaged option and a less environmentally friendly plastic-only- or plastic þ paper-packaged option, they see greater disutility in plastic-only packaging. By extension, they are also willing to pay a greater premium for paperonly packaging when it is presented alongside plastic-only packaging than when it is presented next to plastic þ paper packaging. Taken together, these results suggest that paper-only brands may be able to attract more consumers and command higher premiums if they position themselves against plastic-only alternatives, as opposed to overpackaged plastic þ paper options. Relatedly, we show that minimal packaging can benefit companies using paper-only packaging. For them, superfluous paper packaging creates additional costs without improving consumers’ environmental friendliness perceptions (study A, web appendix D), rendering minimal packaging more attractive. Finally, our findings have implications for package-free retailers, such as Precycle in the United States and Pieter Pot in the Netherlands. Objectively, these stores are more accurately characterized as package free, as they do not feature any single-use packaging, with consumers getting their produce in reusable containers. However, these retailers can also be described as plastic free because they avoid single-use plastics. Our results suggest that the “package-free” positioning, one currently adopted by Precycle, for example, may not be as effective as “plasticfree” positioning, because consumers may not consider additional packaging as problematic and instead focus on minimizing the proportion of plastic in their purchases. To conclude, superfluous packaging, where unnecessary paper is added to plastic packaging, is common across product categories and geographic markets. Companies may use additional paper packaging to communicate greater environmental friendliness and naturalness of their products or to avoid the potential costs of packaging adaptations under minimal packaging. Critically, our research shows that, driven by the PEF bias, consumers may reward companies packaging products with unnecessary paper, showing higher willingness to pay and greater choice propensities for overpackaged items. Thus, it is important to develop interventions that can correct consumer perceptions of environmental friendliness and make them more likely to choose objectively environmentally friendly products. This article attempts to bring attention to consumer perceptions of environmental friendliness, to biases in these

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in the preceding choice tasks. Similarly, in study 4b, the participants likely considered plastic packaging as a comparison standard across the “plastic” and “plastic þ paper” conditions, because they repeatedly saw plastic-packaged Lays and Tyrrells chips alongside the focal Montperal chips package in the choice tasks. Because the PEF bias emerged when participants were likely relying on the same, explicitly provided, comparison standards, it is unlikely that counterfactual thinking is a key driver of our results. In sum, we find initial evidence against several alternative accounts of our results. However, it is possible that the PEF bias is multiply determined, and we hope that future research will further probe the above and other accounts of the PEF bias.

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perceptions, and underscores the need for interventions correcting such biases. We hope that our research will inspire more work in this area.

DATA COLLECTION INFORMATION

REFERENCES Argo, Jennifer and Katherine White (2012), “When Do Consumers Eat More? The Role of Appearance Self-Esteem and Food Packaging Cues,” Journal of Marketing, 76 (2), 67–80. Chandon, Pierre and Nailya Ordabayeva (2009), “Supersize in One Dimension, Downsize in Three Dimensions: Effects of Spatial Dimensionality on Size Perceptions and Preferences,” Journal of Marketing Research, 46 (6), 739–53. Chernev, Alexander and David Gal (2010), “Categorization Effects in Value Judgments: Averaging Bias in Evaluating Combinations of Vices and Virtues,” Journal of Marketing Research, 47 (4), 738–47. Chrysochou, Polymeros and Alexandra Festila (2019), “A Content Analysis of Organic Product Package Designs,” Journal of Consumer Marketing, 36 (4), 441–8. Coelho do Vale, Rita, Rik Pieters, and Marcel Zeelenberg (2008), “Flying under the Radar: Perverse Package Size Effects on Consumption Self-Regulation,” Journal of Consumer Research, 35 (3), 380–90. Dapcevich, Madison (2019), “Trader Joe’s Phasing Out SingleUse Plastics Nationwide Following Customer Petition,” EcoWatch, May 6. Last Accessed August 22, 2022. https:// www.ecowatch.com/trader-joes-plastic-waste-2630818452. html. Deloitte (2022), “How Consumers Are Embracing Sustainability.” Last Accessed December 20, 2022. https://www2.deloitte. com/uk/en/pages/consumer-business/articles/sustainable-con sumer.html. De Langhe, Bart and Stefano Puntoni (2015), “Bang for the Buck: Gain-Loss Ratio as a Driver of Judgment and Choice,” Management Science, 61 (5), 1137–63. Deutsch, Claudia H. (2007), “Incredible Shrinking Packages,” The New York Times, May 12. Last Accessed August 8, 2022. https://www.nytimes.com/2007/05/12/business/12package. html. Dubois, Pierre, Paulo Albuquerque, Olivier Allais, C eline Bonnet, Patrice Bertail, Pierre Combris, Saadi Lahlou, Natalie Rigal, Bernard Rufﬁeux, and Pierre Chandon (2021), “Effects of

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Data for study 1a were collected at the Tilburg University lab in February 2020. Data for studies 1b and 2a were collected via Mechanical Turk in July 2022 and November 2020, respectively. Data for studies 2b, 3, 4a, and 4b were collected via ProlificCo between February and May 2022. Data for study 5 were collected at the University of Michigan lab in February 2022. The first author supervised the data collection and analyzed the data for studies 1a, 2b, 3, 4a, 4b, and 5. The third author supervised the data collection and analyzed the data for studies 1b and 2a. The anonymized data files, syntax files, and study stimuli are stored at https://researchbox.org/712.

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Friendliness for Vehicle Silhouette Design,” Journal of Mechanical Design, 132 (10), 101010. Simonsohn, Uri, Leif D. Nelson, and Joseph P. Simmons (2014), “P-Curve: A Key to the File-Drawer,” Journal of Experimental Psychology: General, 143 (2), 534–47. Smith, Dayna (2020), “The Final Straw?: Evaluating Possible Challenges to Single-Use Plastic Straw Bans Notes,” Texas Environmental Law Journal, 50 (2), 331–52. Spiller, Stephen A., Gavan J. Fitzsimons, John G. Lynch, and Gary H. Mcclelland (2013), “Spotlights, Floodlights, and the Magic Number Zero: Simple Effects Tests in Moderated Regression,” Journal of Marketing Research, 50 (2), 277–88. Sundar, Aparna and Theodore J. Noseworthy (2014), “Place the Logo High or Low? Using Conceptual Metaphors of Power in Packaging Design,” Journal of Marketing, 78 (5), 138–51. Tesco (2022), “Tesco Working with Major Brands to Remove Unneeded Toothpaste Packaging.” Last Accessed December 20, 2022. https://www.tescoplc.com/news/2022/tesco-workingwith-major-brands-to-remove-un-needed-toothpaste-packaging/. United States Environmental Protection Agency (2020), “Containers and Packaging: Product-Specific Data.” Last Accessed February 9, 2023. https://www.epa.gov/facts-andfigures-about-materials-waste-and-recycling/containers-andpackaging-product-specific. van Dam, Ynte K. (1996), “Environmental Assessment of Packaging: The Consumer Point of View,” Environmental Management, 20 (5), 607–14. Wansink, Brian and Pierre Chandon (2006), “Can ‘Low Fat’ Nutrition Labels Lead to Obesity?,” Journal of Marketing Research, 43 (4), 605–17. White, Katherine, Rishad Habib, and David J. Hardisty (2019), “How to SHIFT Consumer Behaviors to Be More Sustainable: A Literature Review and Guiding Framework,” Journal of Marketing, 83 (3), 22–49. Ziano, Ignazio and Mario Pandelaere (2022), “Late-Action Effect: Heightened Counterfactual Potency and Perceived Outcome Reversibility Make Actions Closer to a Definitive Outcome Seem More Causally Impactful,” Journal of Experimental Social Psychology, 100, 104290.

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Behavior,” Journal of Experimental Social Psychology, 81, 15–26. Lin, Ying-Ching and Chiu-Chi Angela Chang (2012), “Double Standard: The Role of Environmental Consciousness in Green Product Usage,” Journal of Marketing, 76 (5), 125–34. Luchs, Michael G., Rebecca Walker Naylor, Julie R. Irwin, and Rajagopal Raghunathan (2010), “The Sustainability Liability: Potential Negative Effects of Ethicality on Product Preference,” Journal of Marketing, 74 (5), 18–31. Magnier, Lise, Jan Schoormans, and Ruth Mugge (2016), “Judging a Product by Its Cover: Packaging Sustainability and Perceptions of Quality in Food Products,” Food Quality and Preference, 53, 132–42. Mai, Robert, Claudia Symmank, and Berenike Seeberg-Elverfeldt (2016), “Light and Pale Colors in Food Packaging: When Does This Package Cue Signal Superior Healthiness or Inferior Tastiness?,” Journal of Retailing, 92 (4), 426–44. Maison, Dominika, Anthony G. Greenwald, and Ralph H. Bruin (2004), “Predictive Validity of the Implicit Association Test in Studies of Brands, Consumer Attitudes, and Behavior,” Journal of Consumer Psychology, 14 (4), 405–15. Martin, Andrew (2008), “Whole Foods Chain to Stop Use of Plastic Bags,” The New York Times, January 23. Last Accessed August 22, 2022. https://www.nytimes.com/2008/ 01/23/business/23bags.html. Meier, Brian P., Amanda J. Dillard, and Courtney M. Lappas (2019), “Naturally Better? A Review of the Natural-Is-Better Bias,” Social and Personality Psychology Compass, 13 (8), e12494. Nielsen, Tobias Dan, Karl Holmberg, and Johannes Stripple (2019), “Need a Bag? A Review of Public Policies on Plastic Carrier Bags—Where, How and to What Effect?,” Waste Management (New York, N.Y.), 87, 428–40. Olsen, Mitchell C., Rebecca J. Slotegraaf, and Sandeep R. Chandukala (2014), “Green Claims and Message Frames: How Green New Products Change Brand Attitude,” Journal of Marketing, 78 (5), 119–37. Reid, Tahira N., Richard D. Gonzalez, and Panos Y. Papalambros (2010), “Quantiﬁcation of Perceived Environmental

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Volume 9, Number 3, 2023

Winter Driving: How to demist your windscreen in double-quick time Demisting your windscreen is a necessity before setting off; not doing so can impede your vision while driving which means you will be driving illegally. The cause of your car windscreen misting up is actually down to water vapour in the atmosphere that occurs when your body heats the air inside the cabin – as does your breath – increasing the amount of moisture it can hold. This means when it comes into contact with your windscreen it cools and condenses, forming a 'mist'. Here's how to clear your windscreen in double-quick time (with a helpful 'life hack' thrown in at the bottom, to help stop your windscreen misting up in the first place). 20th Nov 2022 https://www.rac.co.uk/drive/advice/winter-driving/how-to-demist-your-windscreen-in-double-quick-time/

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Article 9 – Winter Driving - Demisting

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Use the heater correctly Start the heater off cold, then slowly increase the temperature as the air dries out, rather than overloading the cabin with hot, ‘wet’ air. Try to find a temperature and humidity that’s comfortable but doesn’t mist up the cabin. Make sure your heater's blast is directed at the windscreen and the windows - the warmer air (even on cold the air will be warmer than the ice cold windscreen) will dry the glass a little through evaporation and begin to heat up the glass to stop the water vapour condensing on it again. Of course, if you're not in a rush and your frozen bones need warmth then use the hot air to warm both you and the windscreen. It may take a little longer to clear fully but you will at least be a little more comfortable - just don’t move off until all glass surfaces on your car are clear. It’s dangerous and illegal if visibility is impeded. Use the air-con if your car has it If your car has air conditioning make sure it is switched on. Use the air-con in conjunction with the heater. Hot air will dry the glass a little through evaporation, but the air will then cool down and condense on the glass once more, so make sure the air-con is on to keep the atmosphere inside dry. If your windscreen is iced over, then the heat is obviously more necessary. But in this instance you might want to scrape the outside of your windscreen clear first. It is important to keep your windscreen clear in winter. Use your windows If you don’t have a clever climate control system, having the windows down could actually help clear the screen faster. This helps because the dry, cold air from outside can help reduce the amount of water vapour inside the car, stopping the screen misting up. Then you can begin to warm the car up gradually to a temperature that suits you after you have cleared the windscreen. Of course, you should never pull away with your vision impaired, but if your windows start to mist up during driving this is also a worthwhile tactic, for those without air-con. If the misting clouds too much of your vision you should pull over where safe to do so and wait for your windows to clear. Make sure you know the law around fog lights and safe driving in foggy conditions before hitting the roads. Use your climate control system If you do have a clever climate control system, utilise it. There’ll most likely be a setting for demisting the windscreen, which will automatically adjust the ventilation system’s parameters to achieve the best results. Windscreen life hack Keeping your windscreen clean will go a long way to stopping it misting up in the first place. A handy tip to go the extra mile is to actually clean your windscreen with shaving foam. This protective barrier won't last forever and may need to be repeated regularly, but a windscreen cleaned with shaving foam will be less likely to mist up. It's a little trick ice hockey players use to stop their face masks from steaming up when they're on the ice.

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How to clean your windscreen with shaving foam Take a clean towel and place a dollop of shaving foam onto it. Wipe the windscreen with the towel, spreading the shaving foam over the entire surface. Then take another clean towel and wipe off the shaving foam completely. This protective barrier should help stop your windscreen from misting up, but it will need to be regularly reapplied to continue to work.

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Article 9 – Winter Driving - Demisting

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Volume 9, Number 3 2023

10 Top Tips to Improve Your Office’s Productivity Being productive, focused and hardworking can be a key differentiate for an individual, team or business in being successful. So how do you improve people’s productivity? The ability for a CEO or Managing Director to not only maximise his or hers performance but also each individual in the business, can allow them to gain a competitive advantage over their competitors which is why the topic of office productivity and performance is so hot. Here are our top 10 tips to improve your office’s productivity? By Will Vickery Published 28th Aug 2019 https://www.thirstywork.com/articles/10-top-tips-to-improve-your-offices-productivity

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Article 10 – Office Productivity

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Volume 9, Number 3, 2023

1. Tackle the Harder Tasks First Being productive isn’t about working fast. It’s working on what matters and delivers the most value, and ensuring that work is done to a high standard. One of Jeff Bezos’ the founder and CEO of Amazon, top tips for how he remains so productive is always scheduling the toughest meetings and tasks first thing in the morning. Studies have shown that people have the most willpower in the morning, so being able to identify your most important task for the day, and schedule it in for first thing in the morning will give you the best chance of completing that work to a high quality and being able to remain productive throughout the day. 2. Take Breaks Through Out The Day Taking regular breaks throughout the day can be a great method to help you remain focused throughout the day. Focus can often be a factor that affects peoples productivity, so being able to remain focused throughout the day should help improve your offices productivity. Making a coffee, getting a drink of water, having a chat with another colleague on a break or going for a short walk can be great ways to take shorts breaks throughout the day to help you remain being focused. 3. Block Out Distractions Getting distracted by your phone, having a chat with your colleague or surfing the internet can be a serious time waster for people and businesses costing them hours in a day. Each time we lose focus and then switch back to a task it takes a few minutes to get back on track. We can even lose up to 40% efficiency by task switching which has a negative impact on office productivity. Here are some great tips to remove office distractions and improve productivity. Another great method is having certain KPI’s and targets for people which are tracked for example using call tracking software for your telesales team. This creates accountability in the office which should help improve focus and office productivity. 4. Organise Your Day Being prepared and organising your working day when you come into work can be a great way to improve your productivity. Setting your tasks out for each day and prioritising your work will allow you to focus during the day, rather than thinking about what work to do next and when you are going to be able to complete a certain task. Being organised and having a structure to your work will allow you to be consistently productive throughout the week. 5. Avoid Meetings Where Needed Meetings can often be the biggest time waster in a business and have a negative effect on productivity. Especially when a meeting can take hours when same result could have been achieved in a 20 minute meeting. Work with your colleagues to be able to identify when a meeting is needed or when something can be resolved in a quick conversation. Being more selective, to whether you have meetings will allow you to improve your office productivity. 6. Plan For Meetings When you have identified that a meeting is necessary, it is important to be able to achieve the set out result in a timely manner for it to not effect productivity negatively. Some of the best ways to achieve this is by having a set out agenda for the meeting and setting a time scale of when the meeting needs to be achieved by. This will ensure people in the meeting remain focused and allow it to be a productive meeting. 7. Manage Your Emails Effectively Emails can often be a time consuming task for people in the office. So blocking out times in the day to reply to emails can be a great way to ensure your emails don’t build up and effect productivity negatively. Another great way is to respond to urgent emails immediately and then catch up with the non-urgent emails after work. 8. Use Appropriate Team Communication Channels Using appropriate work communication platforms such as WhatsApp, Slack or an internal communications app can be a great way for people to communicate effectively and not effect productivity. Rather than people walking over and chatting to colleagues, they can send a message or email via a communication channel which can then be picked up and responded to without causing a distraction in the office.

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Article 10 – Office Productivity

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9. Dare to Say No Do you often agree to help out a colleague despite having a pressing deadline? If you answered “yes” to this question, the word “no” needs to feature more in your vocabulary. Some of the strategies I’ve already mentioned will help you reinforce boundaries around your time and what you focus on. Inevitably, however, you’ll sometimes be asked to help a colleague out with their work, which you didn’t factor in time for. It’s important to offer support to your colleagues and help them out where possible, but don’t let doing this effect your performance. Question the urgency or priority of a request. But don’t be scared to say no to someone if it’s going to negatively affect your performance. 10. Track & Measure Performance Tracking people’s performance and creating KPI’s that are visible in the office is a great way to create accountability and ensure people remained focused in the office. Having competitions and league tables with your targets are not only a great way to create fun aspects to the working day, but also creates some competiveness which can be great for productivity. These are just some tips to help improve your office’s productivity, which could give you and your business the competitive advantage it needs to continue being successful.

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Article 10 – Office Productivity

PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY TE INTERNATIONAL®

Volume 9, Number 3, 2023

Windows 10 tips and tricks that help you get stuff done faster Time may not necessarily be money, but it still matters. Every second you spend wading through context menus or clunkily navigating Windows is a second you could be doing something you love instead. And with so much of modern life tied up in technology, those wasted seconds can add up fast. Now it’s time to reclaim those lost seconds, minutes, and hours. These simple Windows 10 tips and tricks aren’t glamorous and most aren’t even new, to be honest, but when deployed together they can seriously streamline your workflow. By Brad Chacos, PCWorld, May 30, 2022 3:30 am PDT https://www.pcworld.com/article/397396/windows-tips-optimizations-save-time.html

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Article 11 – Windows Hacks

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Volume 9, Number 3 2023

Adjust your startup programs Let’s start where it all begins: When your computer boots up. Seemingly every program you install worms its way into activating alongside your PC. Some software, such as your keyboard’s management app or your antivirus, deserves that lofty status. Others don’t. (I’m looking at you, game launchers.) And every program that leaps to life when Windows does delays your ability to use your system, especially if you haven’t upgraded to an SSD yet. Fortunately, it’s easy to seize control over which programs launch with Windows. Simply press Ctrl + Shift + Esc or search for “Task Manager” to open the Windows 10 Task Manager, then click on the Startup tab at the top. There, you’ll see all the programs clamoring for a spot in the startup limelight, complete with an estimated impact rating from Low to High. If you want to turn any off, simply click its listing and select Disable. Obviously, doing so means you’ll need to open the program manually to activate it from now on. Customize your task bar Now let’s start organizing things a bit better. Launching a program that’s pinned to your Windows 10 taskbar is always faster than hunting it down in the Start menu or on your desktop. So you’ll want to populate yours with the software and files you use the most. To pin a program to your taskbar, simply right-click it and select the Pin to taskbar option in the context menu that appears. You can also do this to a program’s icon when it appears in your taskbar after opening it. You can pin frequently visited webpages to your taskbar by saving it as a shortcut via your browser’s setting menu, then right-clicking that shortcut on your desktop and selecting Pin to taskbar. Folders can only be pinned to the Start menu, alas. You can pin specific files to your taskbar, kinda-sorta, but the process is slightly different, and brings us to our next tip… Embrace jump lists Now that you’ve pinned your most-used programs to the taskbar, you’re ready to take advantage of the awesomeness known as jump lists. When you right-click a program icon in your taskbar, most will reveal a pop-up list of your most recent open files for that program, or shortcuts to common tasks. It’s a great way to jump right back into a project without needing to slog through folder after subfolder in the Windows File Explorer. Better yet, if you know you’ll constantly return to a particular file or shortcut, you can pin it to the top of the jump list by mousing over its entry, then clicking the pin icon that appears all the way on the right. Any files you do it for will appear under a new “Pinned items” section at the top of the jump list. Simply click the pin icon for an entry again to remove it. Launch taskbar shortcuts with keyboard shortcuts But we’re looking for speed. Unless you’re summoning a jump list to leap back quickly into a specific file, even clicking those icons in your taskbar can be sped up—by not clicking on them. Power users swear by the speed of keyboard shortcuts, and you can open a program on your taskbar without having to lift your hand to your mouse. You used to be able to open specific programs pinned to your taskbar by pressing the Windows key simultaneously with a number associated with where the program is located to the right of the Start Menu— pressing Win + 1 to open your first pinned option, Win + 2 to open the second option, and so on. That seems to have disappeared in Windows 10, though it still works in older versions of the operating system. If you want to use your keyboard to open programs pinned to your taskbar in Windows 10, press Win + T. You’ll see a box appear around the first pinned item to the right of the Start Menu. Press Enter to open it, or keep pressing T to cycle through all your pinned programs from left to right.

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Volume 9, Number 3, 2023

Keyboard shortcuts! Continuing with that theme, keyboard shortcuts are wonderful for performing tasks much quicker than you can by clicking around menus with a mouse. If you’re a keyboard shortcut novice, here’s a sampling of some of the more useful ones: x x x x x x x x x x x x

Crtl + C: Copy Ctrl + X: Cut Crtl + V: Paste Crtl + Z: Undo last action (these Crtl tips work with most software) Alt + Tab: Cycle through open programs Win + Tab: See all open program on a per-monitor basis, summon Windows Timeline Windows key: Open search Windows + E: Open File Explorer Windows + Print Screen: Takes a screenshot and saves it to your Pictures folder Windows + I: Open Windows Settings Crtl + Shift + Esc: Open Task Manager F5: Refresh the active window

If you want to see a full list of all Windows 10 keyboard shortcuts, check out this cheat sheet on Microsoft’s support site. Most—but not all—of them should work with older versions of Windows, too. DIY keyboard shortcuts You don’t have to stop with Windows 10’s native keyboard shortcuts. You can create custom keyboard shortcuts to open programs quickly, too. To do so, right-click the app and select Create shortcut. You’ll see a new icon appear with the same name as the program, but with “shortcut” at the end. Right-click the shortcut for the program and select Properties. In the pop-up menu that appears, select the Shortcut tab, click the Shortcut Key field, and press the alphanumerical key you’d like to associate with the program. Click OK to save the change. Windows will assign Crtl + Alt + <key of your choice> as the keyboard shortcut to open that program. This trick can be seriously useful for wrangling programs that you use often, but not often enough to pin to your taskbar. I like using it for the myriad game launchers installed on my PC, associating the keyboard shortcut’s letter with the first letter of the game launcher’s name. Shut it all down If you’re opening programs and files willy-nilly, you may find yourself drowning in open windows. Fear not: Windows provides several ways to clear the deck near-instantly, returning your focus to the task at hand. My favorite? Click and hold the title bar at the top of the program you’re working in, then give it a vigorous shake. All other windows will be minimized to the taskbar. Pressing Windows + Home accomplishes the same thing. Alternatively, if you want to minimize everything and reveal your desktop, simply press Windows + D on your keyboard, or click the barely-visible sliver all the way to the very right of your taskbar, beyond the system tray and notification center. Poof. Supercharge the Send To menu Staying organized is key to working efficiently. You can use the right-click context menu’s Send To option to keep your virtual house clean, though doing so will require altering the menu to fit your particular needs. Doing so is fast, and well worth the trouble. Start by creating shortcuts to your most-used folders. (I like creating a shortcut for my PCWorld work folder, for instance.) Once that’s done, open File Explorer and type shell:sendto into the location bar at the top. File Explorer will reveal a list of the options that appear in the Send To menu. Simply drag your previously created shortcuts into this folder. Next time you right-click an item and summon the Send To menu, those folders will be listed as options. Happy sorting!

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Article 11 – Windows Hacks

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Volume 9, Number 3 2023

Quick Access or This PC? While you’re in File Explorer, you might want to change the location it opens to. Windows 10 changed things up by having File Explorer default to Quick Access, a view of your most recently used files and frequently used folders. Sounds handy, right? Not so much if you’re already taking advantage of jump lists in your taskbar. If you’ve set up your system as outlined in this guide, you’re much more likely to wade into File Explorer to hunt down infrequently used items—the opposite of what Quick Access provides. Fortunately, you can change how File Explorer behaves and have it open to the “This PC” interface instead, where you can start drilling down into the subfolders on your hard drives. To do so, open File Explorer, click on the View tab, and then click Options. A single option, Change folders and search options, will appear; select it. In the pop-up it summons, open the General tab, click the “Open File Explorer to” drop-down at the top, and select either Quick Access or This PC. Power up Finally, once you’ve mastered these simple yet secret tricks, you could find even more time savings by delving into the exotic world of Windows power tools. Secretive enthusiast-class tools like Timeline, Nearby Sharing, Cloud Clipboard, Storage Sense, and God Mode can help you streamline your workflow even more.

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Article 11 – Windows Hacks

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Volume 9, Number 3, 2023

How to Think Clearly: 7 Tips for Success Have you ever had moments when thinking clearly was just impossible? Times when, no matter how hard you struggled or tried to concentrate, your mind just kept tying itself in knots? If your answer to this question is “yes,” you’re not alone. Everybody thinks they know how to think. But few people have given any real attention to the topic of clear-headed, critical reasoning. It’s difficult to understate the value of clear thinking, both in personal and professional contexts. Individuals who choose to develop this useful skill immediately give themselves an advantage, whether dealing with corporate clients, navigating the tricky parts of a romantic relationship, or so much more. With that in mind, let’s take a look at seven practical ways of developing clear and incisive thinking habits and skills. EU Business School, June 2, 2021 https://www.euruni.edu/blog/how-to-think-clearly-7-tips-for-success/

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Article 12 – Thinking Skills

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What Does “Clear Thinking” Actually Mean? The term “clear thinking” is bandied about a lot. But what does it actually mean? Clear thinking comprises a collection of related skills. Clear thinkers can articulate ideas in an understandable fashion, work logically through problems, infer valid conclusions, and reflect on and account for small details. Fundamentally, clear thinking is about understanding which external conditions encourage lucidity, awareness and concentration and applying the rules of logic and reason to thought-based tasks. Knowing how to structure a sound and valid argument is a big part of the story. But developing consistent habits is equally, if not more, important. 1. Cultivate Mindfulness Mindfulness is a potent tool when it comes to clear thinking. Mindfulness creates “distance” between thoughts, allowing you to evaluate them from an impartial, unemotional position. What’s more, by having greater awareness about your thoughts, you are more likely to notice flaws in your thinking processes and fallacious lines of reasoning. Research into mindfulness is growing rapidly, and studies have demonstrated that mindfulness-based therapies are at least as effective as more established alternatives in some contexts. One easy way of getting started is to set yourself “mindfulness reminders,” which will prompt you to maintain awareness and focus throughout the day. As you might have guessed, there are lots of apps to help with this. 2. Eliminate Distractions Clear thinking requires a certain degree of attentional focus and stability. You need to be able to keep your mind on one thing. If your attention is dispersed because you’re checking WhatsApp messages one moment and reading news stories another, then it’s impossible to fully apply yourself to the kind of in-depth discursive reasoning required to work through arguments, process new information, and form valid conclusions. Organizing your room or going on a social media “fast” may be beneficial over the short term. But to really deal with distractions on an ongoing basis, you need to develop positive long-term habits. Think about ways you can eliminate distractions from your life. Examples might include not using social media during work periods, leaving your mobile phone outside of your office, or blocking news sites during the day. 3. Fuel Your Brain Certain foods, especially refined carbs and those high in added sugar, can cause a state called “brain fog,” in which it becomes difficult to think clearly. What’s more, many healthy foods, including berries, leafy green vegetables, nuts, seeds and even dark chocolate, have been linked to increased brain and memory performance. Making healthy diet choices and opting for non-sugary snacks are among the most practical and immediate things you can do to foster clear thinking. Certain vitamins such as B12, iron, and zinc are also directly linked to cognitive health, so it’s also a good idea to check that you’re getting the right amounts of these essential nutrients.

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FROM THE PUBLISHERS OF PA APER TECHNOLOGY®

Volume 9, Number 3, 2023

4. Start a Daily Meditation Practice Meditation has a wide range of research-backed benefits. When it comes to clear thinking, one positive outcome is particularly notable: relaxation. When you’re stressed and anxious, it becomes difficult to work steadily and thoroughly through a problem. Stress leads to racing thoughts and catastrophizing, neither of which is conducive to clear, effective thinking. Meditating for as little as ten minutes per day can have long-lasting and tangible effects. Setting up a regular daily practice, possibly with the help of an app like Headspace, will increase your overall level of calm throughout the whole day. 5. Organize Your Workspace Ever heard the adage “Tidy room, tidy mind”? Well, it’s not just a throwaway piece of advice that’s uttered by beleaguered parents attempting to get their children to clean their rooms. Studies have shown that organized spaces are good for us. Working in an orderly environment boosts concentration and cultivates calm, both of which contribute to clear thinking. One study also demonstrated a link between reduced clutter and increased academic performance. Cleaning guru Marie Kondo has become a household name in recent years for her revolutionary stance on tidying and streamlining one’s possessions. Her fame and success are likely a result of the real psychological benefits that come from decluttering. 6. Take Regular Breaks (Preferably Outdoors) Breaks have an array of benefits, from eradicating decision fatigue to restoring concentration and motivation. Thinking clearly requires mental resources, and taking breaks allows you to replenish these resources. Human beings have limited attention spans. While omitting breaks to work longer hours may seem like a good idea on the surface, it’s an approach that’s almost certain to diminish productivity. You can also give your breaks an added boost by going outside. Research shows that undertaking activities in nature leads to short and long-term improvements in mental health, including reduced stress and anger, improved mood, and greater self-esteem. 7. Don’t Underestimate the Importance of Sleep Over the last several years, a retinue of scientists, business leaders, celebrities and other public figures have come out to promote the benefits of sleep and dispel the myth that working longer means working better. Good sleep habits are irrefutably linked with mental clarity and better judgment. If you want to think more clearly, ensure that you are getting between seven and eight hours of sleep every night, which seems to be the sweet spot for most people. And if you’re the kind of person that struggles to drift off, try removing artificial sources of light, which are known to inhibit sleep, from your room.

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Article 12 – Thinking Skills

PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY T INTERNATIONAL®

Volume 9, Number 3 2023

Products & Services & News PITA CORPORATE SUPPLIER MEMBERS Page 2 Archroma Compostable range of paper dyes Page 4 ABB Upgraded L&W bursting tester Page 6 ABB advert Page 7 Pilz Configurable PNOZ m C0 base unit Page 9 Pilz PSENmlock mini safety locking device Page 10 Valmet Bearing lubrication monitoring application Page 11 Valmet Rotating consistency sensor

PITA NON-CORPORATE SUPPLIER MEMBERS Page 12 Voith OnCare.Health predictive monitoring solution NON-PITA SUPPLIER MEMBERS Page 14 PCF Maintenance advert Page 15 GTEC Air compressor Page 17 INVENT HYPERCLASSIC® wastewater treatment

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

ARCHROMA ANNOUNCES CERTIFICATION OF COMPOSTABILITY FOR RANGE OF PAPER DYES Archroma, a leading global provider of specialty chemicals and sustainable solutions, announces the certification of a color range of dyes for compostable paper. Colorants from our Carta®, Cartasol® F and Cartafix® range have been meticulously selected to meet the growing demand for environmentally friendlier coloration in the paper industry. As the paper industry strives to adopt more sustainable practices and minimize its environmental impact, compostable materials have gained considerable attention. Compostability plays a crucial role in the circular economy, enabling waste reduction and the generation of valuable organic matter. To ensure the safe and efficient composting of paper products, stringent evaluation criteria have been established, encompassing heavy metals and fluorine content, biodegradation, ecotoxicity and plant growth test assessments. Recognizing the importance of meeting these criteria, Archroma has introduced a range of compostable dyes and fixatives for paper applications that fully satisfy these standards set forth. Archroma's compostable dyes and fixatives for colored paper not only provide exceptional color performance but also meet the most rigorous compostability standards. When applied to compostable materials in a specified concentration of dry weight, our dyes fulfill the evaluation criteria for heavy metals and fluorine, biodegradation, ecotoxicity and plant growth test, as outlined in EN 13432 (2000), NF-T51-800 (2015), ASTM D6400 (2012, 2021), and ISO 17088 (2012). Key features and benefits of Archroma's compostable dyes of the Carta®, Cartasol® F and Cartafix® range for paper include: •

•

• •

Uncompromised color brilliance: Our dyes deliver vibrant, eye-catching colors that meet the demands of the most discerning brands and consumers, ensuring that sustainable papers and products are visually appealing. A complete shade gamut is achievable including deep shades using liquid and powder dyes with fixatives ensuring clear backwater and excellent bleed-fastness. Compliance with international standards: Archroma's dyes are in accordance with globally recognized compostability standards, enabling their adherence to strict requirements regarding heavy metal and fluorine content, biodegradation, and ecotoxicity. The product range is compostability compliant and adheres to food contact regulations specified in BfRXXXVI, ensuring its suitability for food contact paper applications. More sustainable coloration: By utilizing Archroma's range of compostable dyes, manufacturers can significantly enhance the sustainability profile of their products, contributing to a circular economy and reducing the environmental footprint. Reliable performance: These dyes are carefully formulated to offer excellent colorfastness, durability, and stability, ensuring that the colors remain vibrant and consistent throughout the product's lifecycle. The fixatives ensure excellent bleedfastness and clear backwater

To enable customers to unlock the full performance and sustainable potential of our range for compostable colored paper, Archroma has developed a dedicated system that supports industrial compostability for all types of paper, tissues, and packaging applications.

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3 2023

Our system, named DOWN TO EARTH, can be accessed through the online Archroma System Selector: https://www.archroma.com/systems. "At Archroma, we are committed to driving sustainable innovation across industries, and the certification of our compostable dyes represents a significant leap forward in the pursuit of eco-friendly coloration solutions," said Gilles Le Moigne, Packaging & Coating Marketing Manager at Archroma. "By providing paper manufacturers with a range of dyes that meet the strict compostability standards, we empower them to create beautiful, more sustainable products that resonate with today's environmentally conscious consumers." The full range of our compostable dyes https://www.archroma.com/solutions/compostable-dyes.

can

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Products & Services

viewed

here:

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

ABB UPGRADES L&W BURSTING STRENGTH TESTER FOR ACCURATE AND REPEATABLE OPERATOR-INDEPENDENT RESULTS x x x

Latest electronics, touch-screen graphical display and ethernet interface improve usability, automation and digitalization Unique features include an integrated strip feeder and embedded graphical display of the pressure curve within the instrument Upgraded version offers fast testing sequence, safe and ergonomic operation, and digital lab connectivity for automated reporting

ABB has enhanced its L&W Bursting Strength Tester with new features to deliver quicker, easier and more reliable operator-independent testing. Unlike previous generations and competitive models, which require more time and manual effort, the upgraded tester delivers faster results for maximum value and return on investment – all at a competitive total cost of ownership across the lifetime of the product. Bursting strength is an important material property that impacts product performance in paper making, converting and end-use operations. Packaging producers use bursting strength testers to measure a material’s resistance to rupture, optimizing costs and ensuring that the quality and behavior of packaging products meet customer requirements. ABB’s reliable and easy-to-use L&W Bursting Strength Tester includes a large touchscreen, user-friendly interface and increased digitalization to deliver accurate, reliable and repeatable bursting strength results. The new-generation upgrade also features a fast-testing sequence, safe and ergonomic operation, and operator-independent results. ABB’s upgraded L&W Bursting Strength Tester is the only solution on the market to offer: x x x

An integrated strip feeder and diaphragm stiffness compensated results An embedded graphical presentation of the pressure curve within the instrument displaying the elastic tendency of the sample Modern digital and safety features in one instrument

The latest model can also be integrated with other ABB offerings such as the L&W Lab Management System (LMS), which provides connectivity to the full Quality Data Management and Manufacturing Execution System (MES), enabling greater visibility of quality data across the mill and enterprise. “Pulp and paper mill customers that transition to ABB’s new-generation L&W Bursting Strength Tester can look forward to the same long lifecycle as other instruments from the L&W portfolio as well as the benefits with the new technology and digital opportunities,” said Ghazal Amar, Global Product Manager, Paper Testing Equipment at ABB. “Connectivity to digital lab management systems like ABB‘s L&W LMS automates reporting and enables mills to do more in less time.” The L&W Bursting Strength Tester measures a material's resistance to rupture by measuring the maximum pressure of hydraulic fluid needed to rupture a test piece that is tightly clamped between two concentric plates while the pressure is applied by means of a rubber diaphragm expanded by the hydraulic fluid at a controlled rate.

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3 2023

Like other instruments in the product line, critical information and service information can be managed via myABB for L&W.

ABB’s reliable and easy-to-use L&W Bursting Strength Tester includes a large touchscreen, user-friendly interface.

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

Page 6 of 18

Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3 2023

PNOZ M C0 - AS NARROW AS A SAFETY RELAY, BUT AS POWERFUL AS A SAFETY CONTROLLER In the range of safe configurable small controllers PNOZmulti 2 from Pilz, the new standalone base unit PNOZ m C0 is now available. The extremely compact base unit is just 22.5 mm wide and monitors up to four safety functions on machines. Depending on the application, it can be used to implement safety requirements up to the highest category PL (performance level) e or SIL CL 3. As such, the new base unit enables high productivity on smaller machines. As a result, PNOZ m C0 is a safe, high-performance and highly economical solution for small machines in different industries and application areas, such as packaging, on robot cells or in the food and beverage sector, for instance. The extremely narrow PNOZ m C0 has the structural properties of a safety relay, but is as powerful as a configurable safety controller. It provides eight safe inputs and four safe semiconductor outputs on a width of just 22.5 mm. So up to four safety functions can be reliably monitored. These include E-STOP, safety gate monitoring, safety light curtains and two-hand control. Function range and space-saving width ensure that costs are minimised. Digitally supported engineering Also on this standalone base unit, all safety circuits are created via the intuitive software tool PNOZmulti Configurator, the basic version of which is free of licence costs. From Version 11.1, individual safety requirements can be implemented simply and flexibly: for this purpose, the tool provides a large number of approved software blocks for monitoring safety functions up to PL e/SIL CL 3. All created safety architectures can be used independently of a PLC controller. So the safety circuit can be downloaded to the device directly via a USB cable and either saved directly or, alternatively, on the chip card. Digitally supported engineering minimises configuration time and therefore costs for this step in the life cycle. What's more, functions can be expanded or modified at any time. This is particularly beneficial where machines are produced in series, as they can easily be adapted to current requirements. Simply expand if necessary If the number of safety functions on small machines increases, the "small" project can simply be migrated via the software tool. Future expansions of the plant or machine are possible at any time: if more safety functions are required, modular and expandable base units are available, with sufficient performance for machines with a greater function range. Depending on the requirement, the base unit is chosen to match the respective application. Modular, expandable base units also offer high connectivity thanks to connection to all common fieldbus systems, user-friendly diagnostics and web-based visualisation. Users benefit from high flexibility. Solution-oriented, wide-ranging basis In conjunction with for example safety light curtains PSENopt II, the modular safety gate system PSENmlock or the E-STOP pushbuttons PITestop from Pilz, users from the widest range of industries and application areas have a safe, complete, one-stop solution. This provides support in the packaging industry – when palletising or feeding cardboard for example – as well as in the food & beverage industry, on filling machines for instance. And in robotics or special purpose machinery manufacturing, solutions using the new, standalone base unit enable greater productivity and economy on machines. For further information, visit www.pilz.co.uk and search web 225351.

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

New base unit PNOZ m C0 is as narrow as a safety relay, but as powerful as a safety controller.

Page 8 of 18

Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3 2023

NEW SAFETY LOCKING DEVICE PSENMLOCK MINI Strong guard locking. Small and simple to install. The new safety locking device PSENmlock mini for personnel protection expands Pilz’s portfolio of safety switches with guard locking. With its compact design of just 30x30x159 mm, PSENmlock mini is ideal for space-critical applications, such as flaps or covers for example. This small safety locking device has a holding force FZH of 1950 N (F1max: 3900 N), providing safe guard locking for personnel protection applications up to PL d, Category 3 (EN ISO 13849-1). Fast and flexible attachment It can be installed inside or outside the safeguard – to suit your application. Also, the actuator offers a high level of flexibility, as it can be attached from the right, left and front. So swing gates and sliding gates can also be easily safeguarded. High level of safety The dual-channel operation of the solenoid and the bistable guard locking principle provide a guarantee in the event of a power failure: The last state is maintained and the gate is closed. You also benefit from reduced energy consumption. The self-monitoring OSSD outputs enable faults in the wiring to be detected and immediately switch the machine to a safe state in the event of a fault. High degree of manipulation protection The coding is freely selectable – coded, fully coded or uniquely coded. An auxiliary release is integrated on two sides. What’s more, PSENmlock mini can also be connected in series up to PL d, Cat. 3, minimising wiring and simplifying commissioning. In combination with the control unit PITgatebox with integrated access permission system PITreader, the intelligent diagnostic system SDD and the safe small controller PNOZmulti 2, the result is a complete, economical and reliable solution for safeguarding your safety gates. Your benefits at a glance: x x x x x x x x x x

Significant space-saving: 60% smaller than the PSENmlock Strong holding force FZH up to 1950 N (F1max: 3900 N) Simple installation with just two screws Flexible actuator can be installed inside and outside the safeguard and can be attached from the right, left and front High level of safety due to dual-channel operation of the solenoid Bistable guard locking principle ensures safe operation even in the event of a power failure and reduces energy consumption High degree of manipulation protection in accordance with EN ISO 14119; coding freely selectable Safe series connection up to PL d, Cat. 3 can be implemented quickly and simply Optimum economy of the RFID safety switch with protection type IP67 Ideal for use in the packaging, pharmaceutical and food and beverage sector, as well as the machine tool industry

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

VALMET LAUNCHES A NEW MONITORING APPLICATION TO SECURE BEARING LUBRICATION IN FIBER PROCESSING EQUIPMENT Valmet launches a new application, Valmet Oil Monitoring, to remotely monitor oil lubrication in fiber processing equipment. As various rotating machinery throughout the fiberline perform under extremely harsh and demanding environments, it is often difficult to manually retrieve oil samples. Maintaining an adequate surveillance of lubrication properties against harmful effects can prove very challenging. “Valmet’s oil monitoring system provides constant remote lube oil condition monitoring visibility through its novel sensoring and data acquisition technology,” says Heikki Kettunen, Senior Manager, R&D, Rolls and Workshop Services, Valmet. The damages in rotating equipment bearing are mostly related to insufficient bearing lubrication. Typical failure modes such as bearing vibration and elevated temperature are normally only observed when the failure has already progressed. With Valmet Oil Monitoring, upcoming failures can be foreseen through changes in lubrication oil quality. The solution enables corrective actions before the actual failure arises, reducing unplanned shutdowns and the need for subsequent repairs. First application in pulp washing machinery The Valmet Oil Monitoring application was first installed to follow roll bearings’ oil lubrication in a TwinRoll wash press in a European pulp mill. The application detected contamination in the bearing oil circulation unit. This observation was flagged, and the machine operators were able to react quickly with corresponding maintenance actions. Valmet Oil Monitoring, together with the specific applications for chip feeders in continuous cooking and TwinRoll presses in pulp washing, form the offering of Valmet’s modular reliability monitoring platform. The platform is intended for fiber processing equipment and was introduced in 2022. Valmet’s reliability monitoring applications are part of the Valmet Industrial Internet offering and provide powerful tools for fiber producers to secure equipment availability and improve process performance.

Valmet Oil Monitoring system can forecast deterioration before the first signs of bearing failure and, thus, improves process reliability.

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3 2023

VALMET INTRODUCES A NEW ROTATING CONSISTENCY MEASUREMENT FOR PULP AND PAPER PRODUCERS Valmet introduces a redesigned Valmet Rotating Consistency Measurement (Valmet Rotary) for pulp and paper producers. With the latest technology, a new user interface and easier maintenance, the transmitter continues to offer highly accurate fiber consistency measurement for critical applications. “Built on well-known technology and the long experience, the new measurement is robust and built to last. The patented technology ensures rapid measurement response and fast reaction to consistency variations,” says Sami Laaksonen, Product Manager, Automation Systems business line, Valmet. Reliable fiber consistency measurement The redesigned Valmet Rotating Consistency Measurement has a new mechanical design and an electronic solution to improve reliability. Thanks to high sensitivity, the third generation is as accurate as the previous one. The simplified design makes on-site maintenance easier and faster for low overall lifetime costs. Based on shear force measurement technology, Valmet Rotating Consistency Measurement has excellent performance even in challenging environments with high temperature or pressure and abrasive chemicals. A modular design secures a universal use covering consistency range from 1,5 to 16 percent. New user interface for enhanced operation Commissioning, calibration, and operation have been enhanced with a new Valmet Link user interface, a flexible platform with secure remote connection possibilities. With a graphical display and a clear menu structure, set-up and operation are fast and easy. The intuitive user interface and bigger display enable easier calibration and give a better overview of the calibration data. The user interface is prepared for different communication protocols and can be updated for future functionalities.

Valmet Rotating Consistency Measurement and Valmet Link user interface

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

RELIABLE PREDICTIONS FOR AVOIDING UNPLANNED MACHINE DOWNTIME: ONCARE.HEALTH IS COMPLEMENTED WITH ENERGY HARVESTING AND RADIO TECHNOLOGY BASED WIRELESS SOLUTION • OnCare.Health predictive monitoring solution complemented with innovative wireless radio sensors that provide stable measurement quality and robust connectivity • The wireless sensors enable a transmission range of up to 300 m, are temperature resistant up to 120 degrees and self-charging without the need for sensor or battery replacement • Highly efficient system with simple plug & play installation and lowest operating cost Innovative wireless sensors have now been added to the OnCare.Health solution for optimized maintenance efficiency. Based on signals from the new sensors, the predictive monitoring solution automatically detects even minor anomalies and provides early indications of potential defects. OnCare.Health Wireless Solution can be used along the complete papermaking line for all paper grades – from stock preparation to approach flow and along the paper machine on all kind of rotating equipment. In addition, Voith offers access to remote expert service for system care and professional diagnostics support, helping to increase customers overall equipment effectiveness (OEE). Lena Hofmann, Global Product Manager for Condition Monitoring Systems at Voith Paper confirms the benefits of the solution: “Since the new sensors are installed wirelessly, commissioning is much more efficient. For existing plants, we can pinpoint the areas where papermakers benefit from our Wireless Solution. With the help of our proven and intuitive OnCare.Health software, we enable papermakers to easy and reliably monitor the condition of their assets and early identify machine faults. Through provision of information about the related root causes, papermakers reach higher machine availability and maintenance activities can be planned more efficient. The sensor's housing is robust and heat-resistant up to 120°C. Only one gateway is needed to ensure stable transmission quality and extremely stable connections for hundreds of sensors. So far, fewer gateways are needed than with alternative solutions.” Flexible, energy-saving and reliable condition monitoring The wireless sensors use radio technology instead of Bluetooth or WLAN. This allows a transmission range of up to 300 meters within paper mills. Successful customer installations prove the reliability of the new OnCare.Health Wireless Solution. Customers are very satisfied with the solution. Positive comments included the robustness, innovative technology as well as the user-friendliness and handling of the OnCare.Health Wireless System. With just one glance, machine problems become apparent. Views and visualizations can be flexibly adjusted to suit different expert levels. The common interface for online, mobile and wireless measuring points was also positively highlighted. The new wireless sensors are self-charging thanks to an integrated thermal energy recovery unit, making them maintenance-free and requiring no additional energy recovery source. Unlike battery-powered sensors, they do not require regular sensor or battery replacements and have a better environmental footprint. For more information please visit following website: https://voith.com/corp-en/productsservices/automation-digital-solutions/oncare-solutions.html

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3 2023

The innovative wireless sensors enable a transmission range of up to 300 m, are temperature resistant up to 120 degrees and self-charging without the need for battery replacement.

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3 2023

G-TEC AIR COMPRESSOR WORKSTATION IS INDUSTRY GAME-CHANGER Regardless of whether the business is an automotive workshop, a small-to-medium sized manufacturing company or indeed any type of operation that simply needs dry and clean compressed air, the new G-TEC Air Compressor from FPS provides a complete compressed air workstation with ‘game-changing’ capabilities. This 6-in-1 offer comprises a highperformance compressor, refrigerated dryer, dual filtration, 270/500 litre air receiver, oil-water separator and controller, making the G-TEC Air Compressor the optimal and most convenient choice, for a whole host of applications. Avoiding the need for many individual components that typically form part of a complex compressed air system, the G-TEC workstation features an integrated and modular design that saves space, reduces installation and improves efficiency. It delivers outstanding performance, producing a consistent supply of compressed air to power a wide range of pneumatic tools and machinery. With its high-efficiency motor and innovative design, this complete workstation also meets the growing demand for more sustainable and cost-effective compressed air solutions. G-TEC workstations from FPS are available with a range of 7.5 to 22kW with pressure from 8 to 13 bar. The high-efficiency screw compressors ensure optimal productivity and reliability. Importantly, the workstation comes with a 270 or 500 litre receiver and an integrated dryer and filters. The result? Clean, dry air for quality-assured pneumatic operations that lead to reduced downtime and maintenance costs and Indeed, reduced corrosion within pipes that also means fewer product rejects, and fewer costly air leaks, delivering yet more savings. Another integral component of the G-TEC Air Compressor workstation is the condensate oilwater separator, supplied as standard by FPS to reduce environmental pollution. Furthermore, the intuitive built-in control panel makes using the G-TEC workstation easy to use for operators of all skill levels. Among the business that can take advantage are automotive workshops. From tyre centres to body repair shops, the task of paint spraying and when using general garage equipment can benefit from the fixed and variable-speed models of G-TEC Air Compressor line-up. As a particular point of note, noise output is exceptionally low. Further applications include pneumatic tools on production/assembly lines, woodworking tools such as sanders and staplers, and plasma/laser cutting. In all cases the outcome is the same: high-quality, professional compressed air delivery with economy and sustainability in mind. When operating variable-speed models, the remarkable energy-saving capabilities of the G-TEC Air Compressor workstation render it an environmentally responsible choice that also reduces operational costs by as much as 30%. With its fully integrated components, the compact design of the G-TEC Air Compressor makes it ideal for any customer where space is at a premium. This, when combined with straightforward installation and maintenance, allows the G-TEC workstation user the benefit of a hassle-free and highly cost-effective solution for businesses of all sizes. “Users of the G-TEC Air Compressor can achieve the perfect balance between power and efficiency, ensuring that your compressed air needs are met without excessive energy wastage,” states Moiz Palaci, Director of FPS Air Compressors. “At FPS, we are committed to providing innovative solutions that meet the evolving needs of customers. Our G-TEC Air

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

Compressor is no exception, boasting a range of features that make it the ideal choice whenever low noise, energy efficiency, convenience and reliability are primary demands.” Purchase, lease and rental options are available.

The New G-TEC Air Compressor from FPS is a complete workstation with ‘gamechanging’ capabilities.

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3 2023

ENERGY-EFFICIENT AND PROVEN: MIXING AND AERATION SYSTEM FOR AEROBIC TREATMENT IN THE PAPER INDUSTRY INVENT uses the example of a large manufacturer of paper and cardboard products for the pulp and paper industry to show why they are the ideal solution for wastewater treatment in this industry. Some industries are plagued by particularly high energy and water consumption and therefore aim to reduce both sustainably. This is particularly true for the pulp and paper industry. Water treatment plays an essential role here, with INVENT Umwelt- und Verfahrenstechnik AG providing the best suited products. An excellent example of the practical use of INVENT technology in paper wastewater can be found in the north of Germany, more precisely in Varel in the district of Friesland. The Papierund Kartonfabrik Varel (paper mill), located on the outskirts of the small town, employs around 600 people on its site. It is not only a major regional employer but also one of the largest production sites in the German paper industry with a production capacity of around 925,000 tonnes. The mill has a proud history stretching back 84 years. It mainly produces classic raw materials for the packaging industry and has been progressively modernized and expanded over the decades. As early as 1976, the company was one of the first paper mills in Germany to install a biological wastewater treatment plant. As part of the company’s growth, the plant was expanded to a two-step treatment plant in 1994. The next expansions - in which INVENT technology came into action for the first time - took place from 2012 through 2014. HYPERCLASSIC®-Mixing and Aeration Systems were installed in stainless steel cages for aerobic wastewater treatment. One advantage of this cage solution is that it can be removed for installation and maintenance and put back in place, even in a filled tank. The HYPERCLASSIC®-Mixing and Aeration System uniquely combines the characteristics of a mixer with those of an aerator, offering very flexible areas of operation and application. Firstly, it provides sufficient oxygen to the activated sludge during the aerobic process to break down the organic load. Secondly, the aeration tank is mixed homogeneously so that both the heavy activated sludge and small particles are kept in suspension. Due to the energy-efficient operation, high quality and durability of the components the HYPERCLASSIC®-Mixing and Aeration System has made a name for itself as the industry standard in the aerobic treatment of paper wastewater in recent decades. When the operators of the Papier-und Kartonfabrik Varel decided to invest 280 million euros in the production site in 2019, this also entailed a significant expansion of the wastewater treatment plant - and thus an order over another 13 of the trusted HYPERCLASSIC®-Mixing and Aeration Systems with a cage from Erlangen, Germany.

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Products & Services

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

HYPERCLASSIC®-Mixing and Aeration Systems in a cage - mixing and aerating close to the bottom

Page 18 of 18

Products & Services

PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY TEC INTERNATIONAL®

Volume 9, Number 3 2023

CALENDAR OF EVENTS – 2023 / 2024 PITA TRAINING COURSES Mark Smith

Introduction to Wet End Chemistry

7-8 Nov. ‘23

Gernsbach

Fundamentals of Papermaking

5-7 Dec. ‘23

Cristina Lugli

Introduction to Food Contact

20 Feb. ‘24

Peter Luimes

Fundamentals of Wastewater Treatment

12-13 Mar. ‘24

INTERNATIONAL CONFERENCES & EXHIBITIONS DITP

Postojna, Slovenia

15-16 Nov. ‘23

Technologie Kring

Apeldoorn, Netherlands

22-23 Nov. ‘23

Paperex 2023

Delhi, India

6-9 Dec. ‘23

PaperWeek 2024

Montreal, Canada

5-8 Feb. ‘24

Women in Forestry

Online

8 Mar. ‘24

IMPS Symposium

Munich, Germany

19-21 Mar. ‘24

Pulp & Beyond

Helsinki, Finland

10-11 Apr. ‘24

Paper One Show

Sharjah, UAE

16-18 Apr. ‘24

Paper Arabia

Dubai, UAE

14-16 May ‘24

Paper & Biorefinery

Graz, Austria

15-16 May ‘24

Page 1 of 1 Events

PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY TE INTERNATIONAL®

Volume 9, Number 3, 2023

Installations The following pages contain a summary of the various installations and orders from around the world of papermaking, wood panel and saw mills, and bio-power generation, received between the end of June 2023 and the end of October 2023.

Page 1 of 6

Installations

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3, 2023

COMPANY, SITE Alkim Kağıt Kemalpaşa Izmir Türkiye Anon (global packaging and paper manufacturer)

SUPPLIER A.Celli

Asia Symbol Group Guangdong Mill Shandong Mill & Jiangxi Mill China Australian Panels Mount Gambier Australia Billerud Skärblacka Mill Sweden

ABB

Cartiera San Martino S.p.A. Broccostella Paper Mill Italy Drewsen Spezialpapiere Lachendorf Germany

SAEL

Enstra Paper Springs (close to Johannesburg) South Africa

Voith

Göteborg Energi AB Gothenburg Sweden

Valmet

Graphic Packaging Kalamazoo MI USA Graphic Packaging International CRB Mill Waco Texas USA

ProJet

Voith

Siempelkamp

Valmet

Runtech

Voith

Page 2 of 6

ORDER DESCRIPTION to supply a new film size press to apply starch on various paper grades, from 80 gsm copy paper up to 350 gsm Bristol paper. to rebuild its production line into a state-of-the-art production facility for recycled packaging papers to deliver the ABB Ability™ Manufacturing Execution System (MES) and system integration at three tissue mills.

URL Link

Link

to build one of the largest particleboard production lines in Australia. to deliver a complete atmospheric diffuser rebuild, leading to optimised washing and increased capacity. to supply control and automation rebuilding of a laminating machine. to deliver a RunEco vacuum system including Turbo Blower, EcoDrop water separator and EcoFlow dewatering measurement. The Turbo Blower will replace all existing liquid ring pumps on PM2. to rebuild PM6 for packaging paper, including an OCC stock preparation line to improve efficiency, runnability and paper quality. to supply biomass power plant, including a 140MWth Valmet BFB Boiler plant utilizing bubbling fluidized bed technology as well as a flue gas cleaning system and a flue gas condensing system. To supply four ProCleaners for the Forming Wires of their K1Board machine.

Link

to supply complete pulping and wastewater pre-treatment system.

Link

Installations

Link

PAPERmaking! g FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3, 2023

COMPANY, SITE Gulf Paper Manufacturing Mina Abdullah Paper Mill Kuwait Holmen Paper Braviken Mill Sweden

SUPPLIER Toscotec

ORDER DESCRIPTION to supply forming section rebuild for PM2 tissue machine.

URL Link

Andritz

Link

Hubei Xianhe New Materials China

Runtech

Idex Villers-Saint-Paul France ITC Limited Bhadrachalam Sarapaka India JK Paper India

Andritz

to rebuild PM52 for flexible production of book and packaging paper. (Containerboard requires extremely high dewatering capacity and specific strength properties, while book paper needs excellent formation and homogeneous filler retention.) to supply two vacuum systems for PM1 and PM2 (two décor machines). to supply a third waste treatment line to a waste-to-energy centre.

Runtech

to deliver a new vacuum system to upgrade the cartonboard production line.

Link

BTG

Link

Kipas Kagit Turkey Lee & Man Paper Manufacturing Ltd., China Best Eternity Recycle Technology Mill Banting Malaysia Liansheng Pulp & Paper Zhangzhou Fujian Province China

ProJet

to supply Particle Charge Detector PCD-06 for a multilayer board machine. to provide two forming fabric cleaners (PM1). to supply new shoe press to PM26 containerboard machine.

Link

Lucart Aranguren Tissue Mill Spain

Toscotec

to supply a coated board making line (BM2) with related automation systems, bleached chemi-thermo mechanical pulp (BCTMP) technology and two small size tissue machines (TM5 and TM6). In addition, Valmet will supply four tissue machine headboxes for tissue machines TM7, TM8, TM9 and TM10 at the same site. to supply a complete hood system rebuild.

Andritz

Valmet

Page 3 of 6

Installations

Link

Link Link

Link

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3, 2023

COMPANY, SITE Mercer Rosenthal Kraft Pulp Mill Germany

SUPPLIER Valmet

Metsä Tissue Mariestad Sweden

AFRY

Moorim P&P Ulsan Pulp and Paper Mill South Korea

Andritz

Mpact Paper Mkhondo Mill Mpumalanga South Africa Naini Papers Kashipur India

Runtech

Naini Papers Kashipur India

Valmet

National Service Projects Organization Toshka area Egypt The Navigator Company Setúbal Mill Portugal

Andritz

Nordic Paper Bäckhammar Mill Sweden

Andritz

Panda Paper Mills (1997) Netanya Israel

Toscotec

GAW

Andritx

Page 4 of 6

ORDER DESCRIPTION to deliver a Mill-Wide Optimization solution including planning application and change management services to help automate decision-making and optimize the production across the fibre line, recovery line and pulp dryer. to partner in the pre-project and to deliver several services in the construction phase of this Future Mill. to deliver a new HERB recovery boiler, including advanced digitalization solutions, and an ash treatment system. to deliver a vacuum system rebuild.

URL Link

to supply a state-of-the-art coating kitchen with working stations for the new paper machine. to deliver key technologies, automation and services to Naini Papers’ cooking and fiberline rebuild and new specialty paper machine PM3. to supply a complete fiber preparation line for a greenfield plant (HDF/MDF).

Link

to supply a new recovery boiler, new ash leaching system and an upgrade of the non-condensable gases (NCG) collection and incineration system for the pulp mill. to deliver a new wood room with chip and bark handling; the delivery includes a new debarking and chipping line with steam de-icing in the debarking drum, which ensures a high debarking degree with low wood losses and at the same time saves energy to supply a Steel Yankee Dryer, the entire steam and condensate removal system and highefficiency TT Hoods (PM1).

Link

Installations

Link

PAPERmaking! g FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3, 2023

ORDER DESCRIPTION to supply a new tissue line (TM10) capacity 30,000tpy of toilet tissue, kitchen towels and napkins. to supply a press section rebuild.

URL Link

Valmet

to delivery state-of-the art ThruAir drying equipment.

Link

ProJet

to supply four high pressure power cleaners (PM1). to supply a Dynamic Drainage Analyzer 5 (DDA 5).

Link

to provide a three-year service contract with technology for two recovery boilers operating at this dissolving pulp mill. to deliver an electrostatic precipitator (ESP) for the recovery boiler, and automation control equipment for the recovery boiler. supply four Valmet IQ Scanners and two Valmet IQ Moisturizer systems (glassine mill).

Link

to supply machine vision systems for PM6, including a Valmet IQ Web Inspection System, a Valmet IQ Web Monitoring System and winder control with target-stop functionality. to upgrade the current water treatment automation solution with a Valmet DNA Distributed Control System (DCS).

Link

COMPANY, SITE Papel San Francisco Mexicali Mexico

SUPPLIER Valmet

Papeles y Conversiones de Mexico, S.A. de C.V. Guadalupe Mexico Procter & Gamble Box Elder Tissue Mill Utah USA PT. Adiprima Suparinta Indonesia PT Riau Andalan Pulp & Paper Riau Province Indonesia (PT Riau Andalan Pulp & Paper is the operating arm of Asia Pacific Resources International Limited (April) Group). Sappi Saiccor Mill Umkomaas South Africa Shandong Huatai Paper (Pulp project) Shandong province China

Valmet

Shanghai Yongguan Adhesive Products Corp., Ltd. Jiangxi Mill China Shanxi Qiangwei Paper Co., Ltd. China

Valmet

Smurfit Kappa Cartiera di Verzuolo Mill Italy

Valmet

PulpEye

Andritz

Valmet

Page 5 of 6

Installations

Link

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3, 2023

COMPANY, SITE Södra Cell Mörrum Mill Sweden Sofidel Circleville Mill Ohio USA

SUPPLIER Kadant

ORDER DESCRIPTION to supply a Green Liquor System upgrade.

URL Link

Valmet

Link

Softys Altamira Mexico Sonae Arauco Deutschland GmbH Meppen Mill Germany Thai Cane Siam Cement Group Kanchanaburi Thailand Yueyang Forest Paper China

Toscotec

to supply a DCT tissue production line including an extensive automation package, flow control valves and Industrial Internet solutions. to supply a turnkey tissue line including a steel Yankee and shoe press. to supply pressurized refining system (insulation board producer).

ProJet

to provide three power cleaners (dryer fabric cleaners) for PM11.

Link

Andritz

Link

Yueyang Forest Paper China

Valmet

Zain Paper Industry Doha Qatar

Overmade

Zhejiang Jinli Quzhou City Zhejiang Province China

Runtech

to relocate and upgrade a fiberline to produce premium quality fibres for its new paper machine. to supply a high-capacity fine paper making line (PM11) with automation, spare parts and consumables packages. to produce a tissue production facility, the first phase of the project to include the installation of two complete tissue plants (capacity 30ktpy) using softwood and hardwood virgin fibres. to deliver vacuum systems to two new board machines (PM10 and PM11)

Andritz

Page 6 of 6

Installations

Link

PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY TE INTERNATIONAL®

Volume 9, Number 3, 2023

Research Articles Most journals and magazines devoted to the paper industry contain a mixture of news, features and some technical articles. Very few contain research items, and even fewer of these are peer-reviewed. This listing contains the most recent articles from three of the remaining specialist English language journals alongside one Korean journal and one Japanese journal, all of which publish original peer-reviewed research: x x x x x

IPPITA JOURNAL (Peer-reviewed and other) JAPAN TAPPI JOURNAL (English abstract only) JOURNAL OF KOREA TAPPI (English abstract only) NORDIC PULP & PAPER RESEARCH JOURNAL TAPPI JOURNAL

Notes: 1. JAPAN TAPPI JOURNAL is a members-only journal that contains excellent research articles – abstracts are in English but articles are in Japanese. 2. JOURNAL OF KOREA TAPPI is an excellent open-access research journal – abstracts are in English but articles are in Korean.

Page 1 of 6

Research Articles

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

IPPTA JOURNAL, Vol.35(2), 2023 1. A review on the application of biopolymers in food grade packaging. 2. Aptness of paper /paperboard for replacing sups in food packaging. 3. Bamboo as A Solution for Food Packaging. 4. Enhancing Paper’s Barrier Properties for Sustainable Plastic Alternatives. 5. Enhancing Product Quality and Efficiency in Molded Fiber Food Packaging through AI-driven Stiffness Prediction Program. 6. Exploring the Potential of Bacterial Cellulose as a Reinforcing Additive for Enhanced Strength in Food Packaging Papers. 7. From Plastic to Paper: A Sustainable Revolution in Food Packaging. 8. Novel synthesis of Biodegradable Polymer from Cucurbita Peels and Waste Newspaper Sheets. 9. Replacement of single use plastic by paper products in food packaging – An overview. 10. Replacing single use plastic by paper for food packaging applications – developments by wcpm. 11. Sustainable barriers for packaging - opportunities & challenges. 12. Sustainable Fiber Technologies: To Convert Agro-waste into Agro Pulp Suitable for Molded Fiber Packaging. 13. Sustainable Hydrophobic Coating on Paper Based on Natural Rubber Latex and Butyl Stearate. JAPAN TAPPI JOURNAL, VOL.77(7), July 2023 ENERGY SAVING II 1. Case Study of Energy Saving at PM6 after Conversion. 2. Energy Saving by Updating the Instrument Air Supply System. 3. Steam System Optimization and Case Studies in the Paper Industry for Carbon Neutrality. 4. Company-wide Steam Traps Upgrade for Energy Saving. 5. Energy-saving and CO2 Reduction by Means of Fuel Conversion and Other Measures. 6. Energy Savings through the Renewal of the Gas Turbine Cogeneration System. 7. Energy Saving and Work Environment Improvement by Heat Shield Material “Top Heat Barrier”. 8. Development of Ammonia Combustion Technology Development for Coal Fired Power Station. 9. Low-carbon and Decarbonization Approaches for Thermal Energy―Importance of Decarbonizing Across the Continuum from Low-carbon Measures in the Transition Period. Topics & Information 10. Performance Improvement for an ESP, by Replacing T/R sets, Internal Parts and/or by Upgrading to SIR® (Switching Integrated Rectifier). 11. Implementing the Process Optimization Control System㸦Advanced Model Predictive Control) for the Recovery Boiler. 12. Let’s Go Further than Visualization of Product CO2―Introduction of Efforts to Reduce CO2 Emissions. 13. The Improvement of Work Efficiency in Containerboard Warehouse by Using DX and Automatic Devices.

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Research Articles

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

JAPAN TAPPI JOURNAL, VOL.77(8), August 2023 PULP 1. Report on 28th Pulping Seminar. 2. Life Cycle Assessment㸦LCA㸧Basic Method and Recent Trends. 3. Methods for Evaluating the Morphology of Cellulose Fibers at Each Size―From Pulp Fiber to Nanofiber. 4. Pulp Mill without Fossil Fuel―Carbon free Lime Kiln. 5. Basics and Applications Cases of Model Predictive Control in Kraft Pulp Processes. 6. Kraft Pulp Process Inspection Service by Andritz. 7. PulpEye Pulp Analyzer Delivers Mill Cost Savings and Process Performance Improvements―On-line Fiber Properties and Real Time Data Transformation Enabling Process Performance and Product Quality Improvements. 8. Valmet Cooking Process for Low Bulk Density Chips and Energy Savings in the Cooking Process. 9. Pitch Control Agent for the Kraft Pulping Process. 10. Current Situation and Future Prospects of Paper Recycling in Japan. 11. The Latest Detrashing Technology with Intensa Series. 12. Advanced Technology of Handling Recycle Papers with Wet-strength. 13. Initiatives for Carbon Neutral Society in the Use of Ammonia. 14. Development and Evaluation of Cooking Accelerators That Contribute to Building a Carbon-Neutral Industry―Collaboration with the RISE Research Institutes of Sweden AB. Topics & Information 15. The Operating Experience of Kneader. 16. Realtime Prediction Model with using Single Point Morphology SPM-5500―One of the hottest topics in P&P Industry=Visualization of Fiber Morphology. 17. Introduction of Research Laboratories㸦152㸧School of Agriculture, Utsunomiya University Department of Forest Science, Forest Products Laboratory Graduate School of Regional Development and Creativity, Division of Engineering and Agriculture, Graduate Program in Agricultural Biological Chemistry Tokyo University of Agriculture and Technology, United Graduate School of Agricultural Science, Department of Symbiotic Science of Environment and Natural Resources, Major Chair of Science of Forest Resources and Ecomaterials Ltd. JAPAN TAPPI JOURNAL, VOL.77(9), September 2023 Papermaking Technology I 1. Report of the 27th Papermaking Technology Seminar. 2. History of Coating Technology and Latest Trends. 3. Transition and Latest Trend of Tape Turn-Up System―RCS/IBS Reel Changing System. 4. The Synthetic Rubber Cover for Applicator Roll. 5. Basic and Latest Technologies for Calender and Reel. Topics & Information 6. Operating Experience of Fibre Solve FSV㸦U㸧C pulper for Wet Strength Paper Machine Broke Handling. 7. Foreign Matter Removal Technology in the Papermaking Process Using Lowgrade Recycled Paper. 8. The SmartPapyrus Realizes Work Style Reform in Paper Mills㸦Part 1㸧 ―SmartPapyrus® 1.0 System That Classifies Defects by Origin.

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Research Articles

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

The SmartPapyrus Realizes Work Style Reform in Paper Mills㸦Part 2㸧 ―SmartPapyrus® 2.0 That Analyzes and Predicts the Occurrence of Defects.

JAPAN TAPPI JOURNAL, VOL.77(10), October 2023 Papermaking Technology II 1. The Latest Winder Technology. 2. SmoothRun/Active Damping Technology―Reduce Vibration During Winding Process. 3. The Transition and Latest Trends of Roll Wrapping Machine. 4. Sheeter Technology―Challenges and Innovation for Paper and Board Market. 5. Examples of Improvement in Finishing Process. 6. Web Inspection System Technology Trends. 7. The Key Points for Monitoring System to Achieve Efficient and Effective Pest Management. Topics & Information 8. Control of Foam on White Water and Improvement of Operational Efficiency by Modeling a Soft Sensor. 9. Development of Refining Technology. 10. ―Foam Control Solutions that Evolve Day by Day―A Permanent Chemical Approach to Solving Problems in the Papermaking Process. 11. Optimization of Wet-end Process by Slime Control Agent “CURECIDE” and Coagulant “REALIZER”. 12. Visualize and Reduce Fiber Losses by OnView.MassBalance. 13. Paper Chemicals for Environmental Sustainability. 14. Introduction of Research Laboratories㸦153㸧Department of Mechanical Systems Engineering Graduate School of Engineering, Tokyo University of Agriculture and Technology. 15. Pulp and Paper Mills in Japan㸦104㸧Mishima Plant, LINTEC Corporation. JOURNAL OF KOREA TAPPI, Vol.55(3), June 2023 1. A Non-Contact Method for Real-Time Stacked Sheets Counting with X-ray Absorption Spectra and Long Short-Term Memory Network. 2. Characterization of Carboxymethylated Cellulose Nanofiber Made of Cotton Linter Fibers. 3. Study of Physical Defibration of Rice Straw for Pulp Mold. 4. Characteristics of LCMFs and Residual Lignin in the Chemical Micronization of Eucalyptus Wood Meals Using Glycol Ether. 5. Effect of the Pretreatment on the Properties of Cellulose Nanofibril Derived from Recycled Pulp. 6. Fabrication and Characterization of Biomass-derived Superabsorbent Bio-gel. 7. Analysis of Sizing Behavior and Chemical Characteristics of AKD in Paper Using Infrared Spectroscopy. JOURNAL OF KOREA TAPPI, Vol.55(4), August 2023 1. Fractal Dimension Analysis of Surface Roughness for Paper and Paperboard. 2. Sound Absorption Capability of Medicine Herb Residues Mat. 3. ANN Modeling of Drying Kinetics for Molded Pulp Product during Convective and Microwave Drying Process. 4. Characterization of Surface Modification of Woody Biomass Grafted with Acrylic Monomers.

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Research Articles

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

5. 6. 7.

Evaluation of Cellulose Fiber Dispersion in Cellulose Fiber Reinforced Biocomposites using SEM and EDS. Changes in Char Properties according to Carbonization Conditions of Urban Fallen Leaves. Predictive Modeling of Traditional Korean Paper Characteristics Using Machine Learning Approaches (Part 1): Discriminating Manufacturing Origins with Artificial Neural Networks and Infrared Spectroscopy.

NORDIC PULP & PAPER RESEARCH JOURNAL, Vol.38(3), September 2023 1. Paper physics: Out-of-plane uniaxial loading of paperboard: experimental procedure and evaluation. 2. Paper physics: Interlaminar shear modulus of cardboard obtained by torsional and flexural vibration tests. 3. Paper physics: Study on properties of paper coated with Stachys floridana Shuttlew. ex Benth hemicellulose – chitosan composite solution. 4. Paper physics: Analyses of the effects of fiber diameter, fiber fibrillation, and fines content on the pore structure and capillary flow using laboratory sheets of regenerated fibers. 5. Paper chemistry: Preparation and application of epoxy cyclohexane/chitosan/methyl methacrylate composite material. 6. Chemical technology/modifications: Caustic and enzymatic effects on dissolving pulp and its performance as specialty fiber. 7. Bleaching: Microbial xylanase aided biobleaching effect on multiple components of lignocelluloses biomass based pulp and paper: a review. 8. Coating: Effect of cellulose micro/nanofibrils and carboxylated styrene butadiene rubber coating on sack kraft paper. 9. Packaging: The influence of creases on carton board package behavior during point loading. 10. Recycling: Waste newspaper activation using sodium salts: a new perspective. TAPPI JOURNAL, July 2023 1. Editorial: The state of cellulosic nanotechnology: June conference captures current and emerging trends. 2. Effect of fly ash-based calcium silicate on physical properties of cardboard paper. 3. Experimental study and prediction of two-phase flow pattern distribution diagrams in multi-channel cylinder dryer. 4. Effects of metal surface morphology on deposition behavior of microstickies from papermaking white water. 5. Evaporation of process water from recycled containerboard mills. 6. A discrete element method to model coating layer mechanical properties with bimodal and pseudo-full particle size distributions. TAPPI JOURNAL, August 2023 1. Editorial: PEERS and IBBC: TAPPI fall conferences address current and evolving challenges. 2. Energy saving potential of interstage screen fractionation for production of board grade BCTMP. 3. Dynamic CFD modeling of calcination in a rotary lime kiln with an external dryer. 4. Totally chlorine-free peracetic acid pulping for nanocellulose isolation from hemp and poplar.

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Research Articles

PAPERmaking! g g! FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL®

Volume 9, Number 3, 2023

SCC susceptibility of chromized type 409 stainless steel in alkaline chloride solutions at ambient temperature and pressure.

TAPPI JOURNAL, September 2023 1. Editorial: The next phase of research in academia and industry. 2. Perfluoroalkyl and polyfluoroalkyl substances (PFAS) — Fibrous substrates. 3. Filtration efficiency and breathability of selected face masks. 4. Cross-flow separation characteristics and piloting of graphene oxide nanofiltration membrane sheets and tubes for kraft black liquor concentration. 5. Extensive function of green synthesized titania nanoparticles: Photodegradation of Congo red.

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Research Articles

PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY T INTERNATIONAL®

Volume 9, Number 3 2023

Technical Abstracts The general peer-reviewed scientific and engineering press consists of several thousand journals, conference proceedings and books published annually. In among the multitude of articles, presentations and chapters is a small but select number of items that relate to papermaking, environmental and waste processing, packaging, moulded pulp and wood panel manufacture. The abstracts contained in this report show the most recently published items likely to prove of interest to our readership, arranged as follows:

Page 2

Coating Environment Fillers

Page 4

Moulded Pulp Nano-Science

Page 5

Packaging Technology Papermaking

Page 6

Testing

Page 7

Tissue

Page 9

Waste Treatment

Page 10

Wood Panel

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Technical Abstracts

PAPERmaking! g g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3, 2023

COATING Tung oil-based coatings towards sustainable paper packaging materials, F.M. Silva, R.J.B. Pinto, A.M. Barros-Timmons & C.S.R. Freire, Progress in Organic Coatings, VOL.178, May 2023, 107476. Nowadays, the dependence on synthetic plastic-based materials for the preservation and transport of different types of products is very high, leading to major environmental and human health concerns, which highlights the importance of investigating sustainable options. Paper is a widely used bio-based material for packaging however, the development of newer and straightforward approaches to produce paper-based materials with increased functionalities and performance is still highly desired. In this work, we report the use of a bio-based photopolymerizable coating formulation, composed of tung oil, and using Darocur 1173 as photoinitiator, to develop functional papers with hydrophobic and improved water barrier properties, without compromising other properties. Coated paper samples were prepared, using different irradiation times (0, 15, 30, 60, and 300 s), to study the effect of this parameter on the properties of the coated papers. The ensuing coated papers presented pick-up values between 6 and 7 g/m2. Their hydrophobicity was significantly improved as evidenced by the increase in the contact angle values from about 71° to 127° and the significant decrease in the water absorption, measured by the Cobb test, from 108 down to 17 g/m 2, upon a curing time of only 15 s. Furthermore, with this time of curing, the optical (viz. whiteness, brightness, and opacity) and mechanical properties (viz. tensile and burst strength) of paper were not affected. These results highlight the great potential of tung oil photopolymerizable coating formulations as a simple and promising alternative for the fabrication of more sustainable and functional paper packaging materials. ENERGY Thermodynamic analysis of a cogeneration system in pulp and paper industry under singular and hybrid operating modes, Ramadan Hefny Ali, Ahmed A. Abdel Samee & Hussein M. Maghrabie, Energy, Vol. 263, Part E, 15 January 2023, 125964. In the present study, a thermodynamic analysis of a cogeneration system in a pulp and paper industry under different operating modes i.e., singular and hybrid with a variable ambient temperature is conducted according to actual operating data. For singular operating mode, the power boiler is only employed using natural gas while for hybrid operating mode, the power boiler with the recovery boiler is employed using natural gas and black liquor as main fuels, respectively. The results show that for hybrid operating mode in comparison with the singular one, the thermal efficiency of turbine and condenser is enhanced by 1.36 and 7.7%, respectively while it is reduced by 2.8% for the power boiler. In addition, the overall thermal efficiency under singular and hybrid operating modes is 87.4 and 53.7%, respectively. For hybrid operating mode, the exergy destruction of power boiler decreases by almost 10% compared with that for the singular operating mode. Also, at hybrid operating mode, the soda is recovered with a mass flow rate of 33 tons/hour that is required for the cooking process in the chemical pulp section and additionally the consumption of natural gas in the power boiler is reduced by 11.8%. FILLERS Use of waste chicken eggshells as an alternative calcium carbonate source for filler purposes in the paper industry, Gerald Akankunda, Makerere University, Uganda, Undergraduate dissertation. Chicken eggshells, a common waste, are hard, brittle and in abundance. Their abundance has led to their poor disposal. These shells were collected, cleaned and part of them bleached, ground into a powder and the powder analyzed for its suitability as a filler in the paper industry. In the paper industry, fillers are used to reduce on the amount of fiber required in the paper manufacture. Commonly used fillers are

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Technical Abstracts

PAPERmaking! g g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3 2023

calcium carbonate, clay (or kaolin), titanium dioxide and talc (hydrated magnesium silicate). In addition, calcium carbonate can also be used to increase the paper opacity. A fine powder was obtained and the calcium carbonate composition determined for both the unbleached and bleached one. The eggshell powder was analyzed using XRD and results compared with PCC results. The calcium carbonate was found to be 85% and 92.5% for the unbleached and bleached powder respectively. The chicken eggshell powder was found to have magnesium calcite structure. The observed results all aligned the eggshell powder for use as a filler in the paper industry. Preparation of in-situ modified diatomite and its application in papermaking, Zhitian Fan, Zheng Li, Wei Qi, Shuting Zhao, Bing Zhou, Songyan Liu & Yumei Tian, Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 657, Part A, 130582 (20 Jan. 2023). In the paper industry, adding fillers can replace plant fibers in pulp, which is beneficial to environmental protection and cost reduction. However, the large-scale use of inorganic fillers can interfere with interfiber bonding, thereby affecting the physical properties of paper. Due to the loss of fillers and paper fibers, the pollution of paper machine white water is aggravated. In order to improve the above situation, diatomite was used as the matrix and modified by Al(OH) 3 in-situ precipitation. In this study, modified diatomite was used as a papermaking filler. Paper properties, retention and the chemical oxygen demand in papermaking wastewater were also evaluated. The results show that, compared with the blank control, the modified diatomite filler could effectively improve the retention rate and reduce the pollution of paper machine white water while maintaining the physical strength of the paper. Among them, the fiber retention rate of pulp raw material could reach 98.05% and the chemical oxygen demand content of paper machine white water was 30.10 mg L−1. Preparation of Flexible Calcium Carbonate by In Situ Carbonation of the Chitin Fibrils and Its Use for Producing High Loaded Paper, Sang Yun Kim, Sun Young Jung, Yung Bum Seo & Jung Soo Han, Materials 16(8), 2978 (2023). Flexible calcium carbonate (FCC) was developed as a functional papermaking filler for high loaded paper, which was a fiber-like shaped calcium carbonate produced from the in situ carbonation process on the cellulose micro-or nanofibril surface. Chitin is the second most abundant renewable material after cellulose. In this study, a chitin microfibril was utilized as the fibril core for making the FCC. Cellulose fibrils for the preparation of FCC were obtained by fibrillation of the TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) treated wood fibers. The chitin fibril was obtained from the β-chitin from the born of squid fibrillated in water by grinding. Both fibrils were mixed with calcium oxide and underwent a carbonation process by the addition of carbon dioxide, thus the calcium carbonate attached on the fibrils to make FCC. When used in papermaking, both the FCC from chitin and cellulose gave a much higher bulk and tensile strength simultaneously than the conventional papermaking filler of ground calcium carbonate, while maintaining the other essential properties of paper. The FCC from chitin caused an even higher bulk and higher tensile strength than those of the FCC from cellulose in paper materials. Furthermore, the simple preparation method of the chitin FCC in comparison with the cellulose FCC may enable a reduction in the use of wood fibers, process energy, and the production cost of paper materials. Synthesis and characterization of PCC from marble waste for its application in papermaking, Vinod Kumar Dhakad, Prashant Shrivastava, Saakshy Agarwal & Susanta Kumar Jana, preprint not in a peer-reviewed journal, https://doi.org/10.21203/rs.3.rs-3220760/v1. CaCl2 solution and Ca(OH)2 slurry, both prepared from marble waste (MARWAS), were carbonated with CO2 gas in the presence

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Technical Abstracts

PAPERmaking! g g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3, 2023

of CTAB, SDS, Teepol-610s, Triton-X, and Tween-80 as the surface modifiers in a semibatch foam-bed reactor (FBR) to synthesize ultrafine or submicron PCC particles with enhanced hydrophobicity. Nano/ultrafine PPC particles with and without surfactant were also synthesized in a semi-batch stirrer reactor (SR) using CaCl2 solutions made from MARWAS and NH4HCO3 as the carbonating agent by single or simultaneous application of ultrasonication (US) and surfactant, respectively. The products were characterized by SEM, TEM, XRD, FTIR, and drop shape analyzer. In the presence of SDS in the FBR, distinct and smaller hydrophobic (water contact angle of 103.3°) vaterite particles (426 nm) could be produced using CaCl2 solution than those with the Ca(OH)2 slurry. However, in the SR, methanol was found to be more effective than the aqueous solvent in synthesizing needle-like aragonite nanoparticles (215.6 nm with L/D = 8.55) from CaCl2 solution without any use of US or surfactant. Handmade papers were manufactured using ground MARWAS powder, modified and unmodified PCC. The physical, mechanical, and optical properties of these filler-loaded papers were determined. The use of surface-modified and unmodified PCC was superior to the commercial PCC in increasing filler retention, burst strength, tear strength, brightness, and opacity of the paper hand sheets. Even the direct use of MARWAS powder was found to be more effective than GCC in enhancing the optical properties, although a slight decrease in the mechanical strength was observed. MOULDED PULP From agricultural cellulosic waste to food delivery packaging: A mini-review, Jinxing Ma, Jiazhou He, Xiangtong Kong, Junjian Zheng, Lanfang Han, Yi Liu, Zhenchang Zhu & Zhong Zhang, Chinese Chemical Letters, Vol. 34(2), 107407 (Feb. 2023). The growing food delivery service market has boosted the consumption of packaging materials, and this trend is projected to continue in the following years. The gap between industrial supply and consumer demand from a sustainable viewpoint leads to a need for agricultural cellulosic waste-based materials that bring the idea of trash-totreasure to fruition. In this paper, we review up-to-date advancements surrounding the food delivery packaging that are derived from agricultural cellulosic waste. Two scenarios in which agricultural feedstock is used as a host or guest material are summarized, and sketch on the individual processing routine is depicted. We further evaluate how the chemical compositions and processing parameters influence the properties of the final products. Current challenges and gaps in developing sustainable packaging materials are identified, with perspectives on these important issues highlighting the importance of process innovation as well as economic and environmental-impact assessment for agricultural cellulosic waste to food delivery packaging. NANO-SCIENCE Enhancing Strength Properties of Recycled Paper with TEMPO-oxidized Nanocellulose, Eti Indarti, Khairul Hafizuddin Abdul Rahman, Mazlan Ibrahim & Wan Rosli Wan Daud, BioResources, Vol. 18(1), 1508-1524 (2023). Recycled fibers used in the manufacturing of paper and board are associated with strength deficiencies. This study investigated the use of TEMPO-oxidized nanocellulose from oil palm empty fruit bunch (OPEFBTEMPO) for reinforcing papers made from such fibers. Strength properties of tensile and tear were enhanced with the addition of OPEFB-TEMPO, with strong correlations, as indicated by the R² values. The reinforcement capability was supported by the scattering coefficient-percent relationship. The only drawback of the nanocellulose addition is that it reduces pulp drainability, which can be minimized by adding drainage aids. Because only a relatively small amount is required, OPEFB-TEMPO has the potential to be used as paper strengthening agent, particularly in the production of low grammage papers.

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Technical Abstracts

PAPERmaking! g g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3 2023

Engineering the paper production by combined fiber fractionation and reinforcement with microfibrillated cellulose, Reanna Seifert, Samira Gharehkhani, Daniela Vargas Figueroa, Jordan Mercuur & James Olson, Cellulose, Vol. 30, 3201– 3217 (2023). Extending the use of mechanical pulp into non-traditional paper markets that requires moving towards producing high-bulk, porous paper grades with sufficient strength has gained intensive interest. This paper explores the potential of incorporating fiber fractionation with microfibril production to create high-bulk, porous, and strong enough material appropriate for a wide range of non-traditional mechanical pulp applications. Two different pressure-screen fractionation trials were conducted to fractionate a primary pulp into a long and coarse fiber stream (reject) and a fine and short fiber stream (accept). High-bulk, low-tensile sheets were obtained using the long and coarse reject fibers. The accept fibers were low-consistency refined at high specific energy to produce a microfibrilated cellulose (MFC) material and used to strengthen the high-bulk reject pulp sheets. The results illuminated that incorporating highly refined accept fibers having MFCmimetic network into the paper structure could be a promising route to engineer the paper properties and extend the property range in comparison to low consistency refined whole pulp. Different series of handsheets were made and systematically studied by means of fiber length, fine percentage, bulk, tensile index, tensile energy absorption, tear and burst indices, and freeness. Moreover, SEM micrographs were used to interpret the variations of paper properties. We believe that our results shed light on future mechanical pulp materials suitable for packaging and absorbency grades of paper that are high-bulk with sufficient strength for the specific application. PACKAGING TECHNOLOGY Enhancement of barrier properties regarding contaminants from recycled paperboard by coating packaging materials with starch and sodium alginate blends, Valentin Zharkevich, Natallia Melekhavets, Tatsiana Savitskaya & Dzmitry Hrynshpan, Sustainable Chemistry and Pharmacy, Vol. 32, 101001 (May 2023). Novel composite packaging materials based on “clever paper” (CP) (a mixture of polyethylene with calcium carbonate in a mass ratio of ‫׽‬1:1) with a coating layer of biodegradable polymers – corn starch (St) and sodium alginate (Alg) with and without activated carbon – were tested to determine their barrier properties against several substances (undecane, heptadecane, dodecane, triethylcitrate, dipropylphthalate, 4-methylbenzophenone, cholestane) that simulate the migratable contaminants from recycled paperboard. Industrial samples of synthetic films (LDPE, BOPP, BOPET, EVA, PLA, PVA), as well as films based on starch/alginate (St/Alg) blends (St/Alg 90/10 and St/Alg 50/50) have been tested as well. Good barrier properties against the penetration of mineral oils (less than 5% undecane has permeated after 10 days at 40 °C) were demonstrated by the film based on St/Alg 90/10. The coating of CP by a layer consisting of St/Alg 90/10 and activated carbon (AC) yielded the composite material CP/St/Alg 90/10/AC with very low permeability (close to aluminum foil). To further showcase the effectiveness of starch/alginate coatings against penetration of contaminants, additional tests were performed with purchased recycled paper coated by films based on St/Alg 70/30. PAPERMAKING Innovations in papermaking using enzymatic intervention: an ecofriendly approach, Aiman Tanveer, Supriya Gupta, Shruti Dwivedi, Kanchan Yadav, Sangeeta Yadav & Dinesh Yadav, Cellulose, Vol. 30, 7393–7425 (2023). The paper and pulp industry is one of the fastest-growing sectors and has exhibited fast growth in recent years. This is linked to the increased environmental pressure due to the use of virgin fibre from wood as raw material followed by its chemical mediated processing. This prompted the development of

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Technical Abstracts

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Volume 9, Number 3, 2023

technologies that can replace conventional industrial processing. The tree based fibres can be replaced with secondary fibres and enzyme mediated processing can serve as a sustainable alternative to conventional procedures. Cellulase, amylase, pectinase, protease, and xylanase enzymes, as well as a consortium of these enzymes, are commercially available that can efficiently be used for bioretting, biopulping, biobleaching, biodeinking, and biorefining. The eco-friendly bio-based processing has resulted in reduced environmental load as evidenced by the reduction in the BOD and COD values to permissible levels. Enzymes offer significant potential in the production of paper owing to their high efficacy, bio renewability, mildness, non-polluting nature, high selectivity, low cost, and enhanced paper quality. This review intends to draw attention to the effective usage of enzymes for processing in the paper and pulp-based sectors. Biobased processing, alone or in combination with chemicals can prove to be an environmentfriendly approach promoting environmental sustainability. Physical Properties of Pulp and Paper: A Comparison of Forming Procedures, Yingju Miao, Siyu Xiang, Yingfen Wei, Xiaohui Long, Jie Qiu & Yingchun Miao, Forest Products Journal, 73(2), 175–185 (2023). In this work, we used the conventional wet papermaking process and the solution casting procedure to make paper sheets and optimized the relative content of eucalyptus and Simao pine pulps using the mechanical properties of the paper sheet as the evaluation index. The chemical composition, water retention value, zeta potential, carboxyl content, and drainage behavior of the pulp created using the optimal mass ratio for each method were measured, and the resulting paper sheets were characterized via Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and nitrogen adsorption/desorption isotherms. We found that for a ratio of eucalyptus to Simao pine pulps of 94:6 using the wet papermaking process, the mechanical properties of sheets took their optimal values, and the tear, tensile, and burst indexes and the folding endurance were equal to 4.43 mN·m 2·g−1, 27.47 N·m·g−1, 1.13 kPa·m2·g−1, and 11.38 times, respectively, whereas the ratio leading to the best possible mechanical performance in the solution casting process was 88:12, and the corresponding paper sheets had tear, tensile, and burst indexes and the folding endurance of 11.73 mN·m2·g−1, 23.03 N·m·g−1, 0.68 kPa·m2·g−1, and 25.50 times, respectively. The cellulose, hemicellulose, and lignin contents of the pulp treated by the solution casting method were lower by 1.88, 3.11, and 2.67 percent, respectively, compared to that obtained via the wet papermaking process. However, the water retention value, zeta potential, and carboxyl content of the pulp obtained via solution casting were higher by 50.31, 123.41, and 50.15, percent, respectively, compared to that obtained via the wet papermaking process. The drainage time obtained via the solution casting method was one-fifth of that obtained via the wet forming process. The paper sheet prepared via the solution casting method was found to exhibit weaker hydrogen bonding, a decreased level of crystallinity (26.64% lower), and an increased compactness and N2 gas adsorption capacity (19.55% and 66.7% higher, respectively) compared to the sheet obtained via the wet papermaking process. This work shows that the physical properties of the paper prepared via the two processes considered here, using their respective optimal weight ratios of the different types of pulp, have their own advantages. TESTING Alternative Fiber-Based Paperboard Adhesion Evaluation with T- and Y-Peel Testing, Urška Kavčič, Gregor Lavrič & Igor Karlovits, Appl. Sci., 13(17), 9779 (2023). Due to increased pressure on the availability of wood biomass in the EU and the regulatory attempts to lower CO2 values, where wood-based biomass plays a crucial role in carbon sequestration, the use of cellulose derived from alternative sources is gaining

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Volume 9, Number 3 2023

increased interest in the pulp and paper industry as well as in other industries. The processing properties of alternative fiber-based packaging need to be checked in current processing operations with other types of materials and recycling workflows. For example, in the production of folding boxes, after printing other converting properties such as glueability are also of great importance. The adhesive absorption and bonding strength of materials are important as adhesive joints of packaging can interfere with the protective function. In the presented research, three different paperboards produced on a pilot scale from alternative raw material sources were tested. Two paperboards were produced from the alien invasive plants Japanese knotweed and black locust, and one from residual sawdust. The basic paperboard properties were tested regarding paperboard porosity, roughness, z-directional tensile strength, and dynamical behavior regarding liquid interaction (contact angle and liquid penetration dynamic), as water-based adhesives were used in the research. For adhesive joint strength testing, Y- and T-peel adhesion testing was performed on the joint paperboard samples, as still there is no fully standardized method for the evaluation of such fiber-based material properties. The results indicate differences in the penetration dynamics of liquids. This parameter had the highest influence on the peel adhesion strength, while porosity, roughness, and dynamic contact angle were not so significant. Regarding the two adhesive joint tests, the differences in separate materials regarding peel adhesion curves show similar results. However, the Ypeel maximum force values are higher due to the testing setup (in comparison to the Tpeel test). The paperboards made from invasive plants showed adhesive joint failures which are more suitable for tamper-proof packaging due to their low surface strength and crack propagation into the fiber structure. An Analysis of Numerical Homogenisation Methods Applied on Corrugated Paperboard, Rhoda Ngira Aduke, Martin P. Venter & Corné J. Coetzee, Math. Comput. Appl., 28(2), 46 (2023). Corrugated paperboard is a sandwich structure composed of wavy paper (fluting) bonded between two flat paper sheets (liners). The analysis of an entire package using three-dimensional numerical finite element models is computationally expensive due to the waved geometry of the board that requires the use of a relatively large number of elements in a simulation. Because of this, homogenisation approaches are used to evaluate equivalent homogenous models with similar material properties. These techniques have been successfully implemented by various researchers to evaluate the strength of corrugated paperboard. However, studies analysing the various homogenisation techniques and their ranges of applicability are limited. This study analyses the application of three homogenisation techniques: classical laminate plate theory, first-order shear deformation theory and deformation energy equivalence method in the evaluation of effective elastic material properties. In addition, inverse analysis has been applied to determine the effective properties of the board. Finite element models have been used to evaluate the accuracy of the three homogenisation techniques in comparison to the inverse method in modelling four-point bending tests and the results reported. TISSUE Converting Operations Impact on Tissue Paper Product Properties – A Review, Joana C. Vieira, Paulo T. Fiadeiro, & Ana P. Costa, BioResources, Vol. 18(1), 23032326 (2023). Tissue paper is deep-rooted in our daily life because of its different types of products that allow various applications. Tissue paper is a low grammage paper that is mainly characterized by softness, tensile strength, liquid absorption, and elasticity. These characteristics are essential when producing products such as toilet paper, kitchen rolls, hand towels, napkins, and facials. The tissue paper production involves two stages:

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PAPERmaking! g g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3, 2023

formation of the tissue paper sheet itself and its converting into different finished products. Converting is characterized by several operations, namely: unwinding, winding, embossing, lamination, perforation, cutting, packaging, and palletizing. The most impacting operation is the embossing, which consists of marking a pattern on the paper sheet by applying pressure, with the intent to produce papers more aesthetically pleasing to the final consumer and/or a way to identify a particular brand. Also, it affects final properties, increasing the liquid absorption capacity and bulk but reducing softness and tensile strength. Converting is complex and has a huge impact on the finished products properties. In this review, the authors explored the different steps of converting and how they impact the different properties of finished tissue products. Environmental Life Cycle Assessment of Premium and Ultra Hygiene Tissue Products in the United States, Amelys Brito, Antonio Suarez, Alonzo Pifano, Lee Reisinger, Jeff Wright, Daniel Saloni, Stephen Kelley, Ronalds Gonzalez, Richard Venditti & Hasan Jameel, BioResources, Vol. 18(2), 4006-4031 (2023). Under the controversial concern of using virgin fibers in hygiene tissue products, mostly Bleached Eucalyptus Kraft (BEK) and Northern Bleached Softwood Kraft (NBSK), consumers are responding by purchasing selflabeled sustainable products. As of today, there are no established sustainability reported results to inform consumers about the carbon footprint of hygiene tissue. To fill this gap, this study used Life Cycle Assessment to evaluate the environmental impacts across the supply chain (cradle to gate) to produce Premium and Ultra grades of bath tissue, including the production of feedstock, pulp production, and tissue production stages, with focus on Global Warming Potential (GWP). The results showed that one air-dried metric ton (ADmt) of BEK pulp had an associated GWP of 388 kgCO2eq, whereas one ADmt of NBSK pulp presented values ranging between 448 and 596 kgCO2eq, depending on the emissions allocation methodology used. It was estimated that the GWP of one finished metric ton of tissue weighted average could range from 1,392 to 3,075 kgCO2eq depending on mill location, electricity source, and machine technology. These results provide an understanding of the factors affecting the environmental impact of hygiene tissue products, which could guide manufacturers and consumers on decisions that impact their carbon footprint. Robust optimization and data-driven modeling of tissue paper packing considering cargo deformation, João P.L. Coutinho, Marco S. Reis, Diogo Filipe Martins Gonçalves Neves & Fernando P. Bernardo, Computers & Industrial Engineering, Vol. 175, 108898 (Jan. 2023). This paper considers the container loading problem (CLP) for efficient packing of low density tissue paper products, for which, volume, instead of weight, is the key driver for logistic decision-making. Tissue products are susceptible to deformation during the packing process. However, this aspect is usually overlooked when defining the optimal packing policy. In this work, we take this aspect into account and develop a novel methodology for CLP optimization of tissue paper products. The deformation is modeled as a function of known product characteristics and packing process variables using data-driven models. Several modeling approaches are compared, including those based on variable selection, regularization and projection to latent variables. The data-driven model is then included into a Mixed Integer Non Linear Programming (MINLP) CLP. A worst-case robust optimization approach is considered, resulting in solutions that are robust against data-driven model uncertainty. The methodology is applied to a real case study from a portuguese tissue paper mill concerning the packing of toilet paper rolls in wood shipping pallets. Predicted results show an average gain of 4 to 7% in load density in the worst-case scenario, compared to current practice. The deformation model is validated experimentally on the industrial site,

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Volume 9, Number 3 2023

by testing optimal configurations which show gains in load density up to 40%. The methodology can be easily extended to other tissue paper products as well as any low density product showing reversible deformation during packing. Multi-tier supply chain sustainability in the pulp and paper industry: a framework and evaluation methodology, Bo Feng, Xueyan Hu & Ifeyinwa Juliet Orji, International Journal of Production Research, Vol. 61(14) (2023). The pulp and paper industry has significant sustainability implications and necessarily requires a careful consideration of direct and lower-tier suppliers for effective sustainable supply chain management. This paper utilized an extensive literature review and semi-structured interviews of experts in the Chinese pulp and paper industry to unearth the factors that highly influence multi-tier supply chain sustainability. A Technological-OrganizationalEnvironmental (TOE) and Human-Organizational-Technological (HOT-fit) based theoretical framework was employed to classify the identified factors. Then, an Analytical Hierarchy Process (AHP) based methodology was applied to determine the relative importance of the factors. A comparison analysis of the relative importance of the factors as determined by the experts in the focal companies, Tier-1 suppliers and Tier-2 suppliers of the Chinese pulp and paper industry is presented. The results show that institutional and technological factors are most critical to actualizing multi-tier supply chain sustainability. Thus, the study outcomes present relevant theoretical and practical implications for the managers and practitioners in the pulp and paper industry on how to facilitate multi-tier supply chain sustainability for increased competitiveness. Furthermore, this study provides guidelines for other industries as well and sets the stage for subsequent theorization and exploration of multi-tier supply chain sustainability for expected performance gains. WASTE TREATMENT Reducing freshwater consumption in pulp and paper industries using pinch analysis and mathematical optimization, Ali Esmaeeli & Mohammad-Hossein Sarrafzadeh, Journal of Water Process Engineering, Vol. 53, 103646 (July 2023). The pulp and paper (P&P) industries are classified among the water-intensitive industries. In this work, implementation of the Water Closed-Loop System (WCLS) in a P&P factory to reduce water consumption and wastewater generation was reported. First, the water and steam network of the mill was synthesized, and water sinks and sources along with their flowrates were identified. The key pollutants, including chemical oxygen demand (COD), total suspended solids (TSS), and total dissolved solids (TDS), were pinpointed and acceptable levels for water sinks were acquired. In the second step, by using water pinch analysis with the direct-reuse approach, each limiting pollutant was investigated, and the maximum reduction in freshwater consumption equal to 36.9 % was obtained by considering TSS as the only pollutant. The minimum potential for reducing water consumption belonged to COD (4.0 %) and TDS (18.9 %). In the regeneration-reuse approach, the incomplete performance of the mill's treatment plant in removing COD and TDS resulted in no improvement in the results of the previous step. In the case of TSS alone, the reduction in freshwater consumption increased to 93.3 %. Mathematical optimization was used to study all limiting contaminants simultaneously. The direct-reuse approach achieved a 4.0 % reduction in water consumption, while the regeneration-reuse did not change water consumption compared to the direct-reuse approach, emphasizing the incomplete operation of the treatment plant. Finally, the output contaminants levels of a hypothetical decentralized and modified existing treatment plant were estimated using literature. In this case, the freshwater consumption of the mill declined by 93 %.

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Volume 9, Number 3, 2023

The performance and microbial community of anaerobic membrane bioreactor for high calcium papermaking wastewater treatment, Mingchao Zhu, Jingwei Wang, Danni Pei, Ji Sun, Yangze Lu, Zhaoxia Hu, Shouwen Chen & Na Li, Journal of Water Process Engineering, Vol. 56, 104311 (Dec. 2023). High calcium papermaking wastewater challenges anaerobic biological technology applications, leading to sludge calcification and unstable reactor operation. This study employed an anaerobic membrane bioreactor (AnMBR) to treat high-calcium papermaking wastewater (1000 mg/L) and achieved an average chemical oxygen demand removal efficiency of 90.1%. No significant accumulation of volatile fatty acids was observed during the entire experimental period. The methane production capacity decreased with the increasing inlet calcium ion concentration, and the maximum methane production rate in Stage 4 was 115.4 mL·(gVSS·d)−1. The maximum transmembrane pressure reached was 4.33 kPa, and the sludge was primarily present in the form of flocs due to the hydraulic shear effects. Anaerolineaceae, Bacteroidetes_vadinHA17, Methanosaetaceae and Methanobacteriaceae were identified as the dominant bacterial species in Stage 4, correlating with the robust anaerobic digestion performance. In conclusion, the AnMBR exhibited a reliable and effective treatment method for high calcium papermaking wastewater. Ionic resource recovery for carbon neutral papermaking wastewater reclamation by a chemical self-sufficiency zero liquid discharge system, Yangbo Qiu, Sifan Wu, Lei Xia, Long-Fei Ren, Jiahui Shao, Jiangnan Shen, Zhe Yang, Chuyang Y Tang, Chao Wu, Bart Van der Bruggen & Yan Zhao, Water Research, Vol. 229, 119451 (1 Feb. 2023). Papermaking industry discharges large quantities of wastewater and waste gas, whose treatment is limited by extra chemicals requirements, insufficient resource recovery and high energy consumption. Herein, a chemical self-sufficiency zero liquid discharge (ZLD) system, which integrates nanofiltration, bipolar membrane electrodialysis and membrane contactor (NF-BMED-MC), is designed for the resource recovery from wastewater and waste gas. The key features of this system include: 1) recovery of NaCl from pretreated papermaking wastewater by NF, 2) HCl/NaOH generation and fresh water recovery by BMED, and 3) CO2 capture and NaOH/Na2CO3 generation by MC. This integrated system shows great synergy. By precipitating hardness ions in papermaking wastewater and NF concentrate with NaOH/Na2CO3, the inorganic scaling on NF membrane is mitigated. Moreover, the NF-BMED-MC system with high stability can simultaneously achieve efficient CO2 removal and sustainable recovery of fresh water and high-purity resources (NaCl, Na2SO4, NaOH and HCl) from wastewater and waste gas without introducing any extra chemicals. The environmental evaluation indicates the carbon-neutral papermaking wastewater reclamation can be achieved through the application of NF-BMED-MC system. This study establishes the promising of NF-BMEDMC as a sustainable alternative to current membrane methods for ZLD of papermaking industry discharges treatment. WOOD PANEL A Dialdehyde Starch-Based Adhesive For Medium-Density Fiberboards, Nicolas Neitzel, Reza Hosseinpourpia & Stergios Adamopoulos, BioResources, 2023, Vol. 18(1), 2155-2171 (2023). Bio-based adhesives have gained considerable attention in the last years as more sustainable and healthier alternatives to the formaldehyde-based adhesives used today in wood-based panel manufacturing. In this study, dialdehyde starch (DAS) with various aldehyde contents was prepared by using sodium metaperiodate as an oxidizing agent. Characterizations were performed by employing Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and thermal stability analysis. Different

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Volume 9, Number 3 2023

adhesive compositions were used for making medium-density fiberboard (MDF) panels. They were based on DAS (12 wt% based on fiber), emulsifiable diphenylmethane diisocyanate (eMDI, 2-4 wt% based on DAS), and microfibrillated cellulose (MFC, 0.5-1.0 wt% based on DAS). Fibers and the adhesive components were mixed with a combination of dry mixing and wet spraying. The physical and mechanical properties of MDF panels bonded with different DAS-based adhesives were compared with those of melamine ureaformaldehyde (MUF) adhesive and sole eMDI. The results showed that the MDF panels made with DAS-MFCeMDI of 99.52% bio-based content showed comparable properties to standard panels with a commercial MUF adhesive. It was implied that DAS in the presence of small amount of eMDI can create strong bonds with wood fibers, while an additional positive effect on bonding was due to the contact surface enlargement of MFC. Particleboard panels made with sugarcane bagasse waste—an exploratory study, Nara Cangussu, Patrícia Chaves, Welis da Rocha & Lino Maia, Environmental Science and Pollution Research, Vol. 30, 25265–25273 (2023). The reuse of natural fibers, in order to manufacture a new product, is already becoming popular due to the generation of a series of advantages in social areas. Sugarcane bagasse is a set of tangled fibers of cellulose, produced in large quantities due to increased acreage and industrialization of sugarcane resulting from public and private investments in production aimed for the alcohol industry. The aim of this study was to evaluate the feasibility of producing sheet timber manufacture from the sugarcane bagasse, analyzing mechanical strength properties. A form of metal sheet for the molding of 12 specimens based on sugarcane bagasse and industrialized resin was made. Soon after molding, specimens were submitted to a three-point bending test, with the aid of a press. The analysis of the results allowed to conclude that the tensile strength and the modulus of elasticity did not obtain the minimum values recommended by the standard. The tensile strength must be improved to allow panels to be useful for ordinary strength applications. Comparison on greenhouse gas footprint of three types of oriented strand board manufacturing process in China, Wan-Li Lao, Xin-Fang Duan & Xiao-Ling Li, Environmental Science and Pollution Research, Vol. 30, 78793–78801 (2023). The greenhouse gas (GHG) footprints of oriented strand boards (OSB) have been gaining growing concern. China is one of the largest manufacturers and traders of OSB in the world. However, little data are available concerning the GHG footprint of Chinese OSB production. The purpose of this study is to quantify and compare the GHG footprints of three types of OSB produced in China. Cradle-to-gate GHG footprints assessment models were built for OSB according to PAS 2050 guidelines. The results showed that the cradleto-gate GHG footprints of OSB/2, OSB/3, and OSB/4 were 142.7 kg CO2 e/m3, 173.2 kg CO2 e/m3, and 374.2 kg CO2 e/m3, respectively. Raw material acquisition was the largest contributor to GHG footprint for three types of OSB (52.6~57.6%), followed by the production process of OSB (25.6~27.3%) and transportation (15.3~20.1%). The consumption of wood, MDI, electricity, and the transportation of wood were main emission hotspots in Chinese OSB production. Ultimately, four feasible GHG emission reduction measures were put forward from the perspective of reducing the usage of wood and MDI adhesive, decreasing the electricity consumption, and shortening the transport distance of wood. Analysis of the interaction between internal porosity and oriented strand board performance using X-ray computed tomography, Biaorong Zhuang, Alain Cloutier & Ahmed Koubaa, European Journal of Wood and Wood Products, Vol. 81, 99–109 (2023). The internal structure of oriented strand board (OSB) is made of a large number of

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Technical Abstracts

PAPERmaking! g g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ®

Volume 9, Number 3, 2023

voids. This results from the complexity of strand distribution within the panel and impacts panel performance greatly. In this research, X-ray microcomputer tomography was used to investigate the void characteristics of OSB panels with different structures. The results indicated that OSB panels have a porosity profile opposite to that of density. Unidirectionally oriented homogeneous boards showed slightly higher total porosity, a steeper porosity profile, and higher void size than other three-layer boards. Still, there was no significant difference between them. Although the changes in bending properties resulted from changes in core layer strand orientation, the slight difference in internal bond and water absorption rate was caused by the narrower void distribution and a larger void size. Panels containing a mixture of black spruce and aspen strands had a higher porosity, a steeper porosity profile, and a small void size compared to panels with black spruce strands. This resulted in better bending properties, worse internal bonding, and a lower water absorption rate and thickness swelling. Thus, the internal bond, water absorption rate, and thickness swelling of the panels with a mixed spruce-aspen core layer decreased with an increase in core layer proportion. An opposite trend was observed for panels with a black spruce core layer. Physical and Mechanical Properties of High-Density Fiberboard Bonded with BioBased Adhesives, Aneta Gumowska & Grzegorz Kowaluk & Grzegorz Kowaluk, Forests, 14(1), 84 (2023). The high demand for wood-based composites generates a greater use of wood adhesives. The current industrial challenge is to develop modified synthetic adhesives to remove harmful formaldehyde, and to test natural adhesives. The scope of the current research included the manufacturing of high-density fiberboards (HDF) using natural binders such as polylactic acid (PLA), polycaprolactone (PCL), and thermoplastic starch (TPS) with different resination (12%, 15%, 20%). The HDF with biopolymers was compared to a reference HDF, manufactured following the example of industrial technology, with commonly used adhesives such as urea-formaldehyde (UF) resin. Different mechanical and physical properties were determined, namely modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding strength (IB), thickness swelling (TS), water absorption (WA), surface water absorption (SWA), contact angle, as well as density profile; scanning electron microscope (SEM) analysis was also performed. The results showed that increasing the binder content significantly improved the mechanical properties of the panels in the case of starch binder (MOR from 31.35 N mm −2 to 40.10 N mm−2, IB from 0.24 N mm−2 to 0.39 N mm−2 for dry starch), and reduces these in the case of PLA and PCL. The wet method of starch addition improved the mechanical properties of panels; however, it negatively influenced the reaction of the panels to water (WA 90.3% for dry starch and 105.9% for wet starch after 24 h soaking). Due to dynamically evaporating solvents from the PLA and PCL binding mixtures, a development of the fibers’ resination (blending) techniques should be performed, to avoid the uneven spreading of the binder over the resinated material.

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Technical Abstracts