NaturalFiber-ReinforcedComposites
ThermalPropertiesandApplications
EditedbySenthilkumarKrishnasamy,SenthilMuthuKumar Thiagamani,ChandrasekarMuthukumar,RajiniNagarajan,and SuchartSiengchin
Editors
Dr.SenthilkumarKrishnasamy DepartmentofMaterialsandProduction Engineering
TheSirindhornInternational Thai-GermanGraduateSchoolof Engineering(TGGS) KingMongkut’sUniversityof TechnologyNorthBangkok 1518WongsawangRoad,Bangsue Bangkok,10800 Thailand
Dr.SenthilMuthuKumarThiagamani DepartmentofMechanicalEngineering KalasalingamAcademyofResearchand Education Krishnankoil,626126 AnandNagar,TamilNadu India
Dr.ChandrasekarMuthukumar SchoolofAeronauticalSciences HindustanInstituteofTechnology& Science Padur,Kelambakkam Chennai,603103,TamilNadu India
Prof.RajiniNagarajan DepartmentofMechanicalEngineering KalasalingamAcademyofResearchand Education Krishnankoil,626126 AnandNagar,TamilNadu India
Prof.SuchartSiengchin DepartmentofMaterialsandProduction Engineering
TheSirindhornInternational Thai-GermanGraduateSchoolof Engineering(TGGS) KingMongkut’sUniversityof TechnologyNorthBangkok 1518WongsawangRoad,Bangsue Bangkok,10800 Thailand
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Contents
Preface xiii
1ThermalCharacterizationoftheNaturalFiber-BasedHybrid Composites:AnOverview 1
ChandrasekarMuthukumar,SenthilkumarKrishnasamy,SenthilMuthu KumarThiagamani,RajiniNagarajan,andSuchartSiengchin
1.1Introduction 1
1.2ThermalCharacterization 3
1.2.1DMA 3
1.2.2TMA 5
1.2.3DSC 6
1.2.4TGA 6
1.3Conclusion 10 Acknowledgment 11 References 11
2ThermalPropertiesofHybridNaturalFiber-Reinforced ThermoplasticComposites 17
A.Vinod,YashasGowda,SenthilkumarKrishnasamy,M.RSanjay,and SuchartSiengchin
2.1Introduction 17
2.2ThermalProperties 18
2.2.1ThermogravimetricAnalysis(TGA) 18
2.2.2DifferentialScanningCalorimetry(DSC) 20
2.2.3ThermomechanicalAnalysis(TMA) 21
2.2.4DynamicMechanicalAnalysis(DMA) 23
2.2.5MeltFlowIndex(MFI) 24
2.3Conclusions 25 References 26
3ThermalPropertiesoftheNaturalFiber-ReinforcedHybrid PolymerComposites:AnOverview 31
JyotishkumarParameswaranpillai,SenthilkumarKrishnasamy,Suchart Siengchin,SabarishRadoor,RoshnyJoy,JinuJacobGeorge,Chandrasekar Muthukumar,SenthilMuthuKumarThiagamani,NisaV.Salim,andNishar Hameed
3.1Introduction 31
3.2ThermalPropertiesofNaturalFiberComposites 33
3.2.1ThermogravimetricAnalysis(TGA) 33
3.2.2DifferentialScanningCalorimetry(DSC) 38
3.2.3DynamicMechanicalAnalysis(DMA) 41
3.3Conclusion 45 Acknowledgment 45 References 46
4ThermalPropertiesofSugarPalmFiber-BasedHybrid Composites 53
R.A.Ilyas,S.M.Sapuan,A.Atiqah,M.R.M.Asyraf,N.M.Nurazzi,MohdN.F. Norrrahim,MohdA.Jenol,M.M.Harussani,R.Ibrahim,M.S.N.Atikah,and ChandrasekarMuthukumar
4.1Introduction 53
4.2ThermalAnalysisofSugarPalmFiber-BasedHybridComposites 58
4.2.1TGAPropertiesofSugarPalmComposites 58
4.2.2TGAPropertiesofSugarPalmHybridComposites 60
4.3DynamicMechanicalPropertiesofSugarPalmFiber-BasedHybrid Composites 63
4.3.1SugarPalm/GlassFiber 63
4.3.2SugarPalm/CassavaBagasse 66
4.3.3SugarPalm/Flax 66
4.4PotentialApplications 66
4.5Conclusions 72 Acknowledgment 72 References 72
5ThermalPropertiesofSisalFiber-BasedHybrid Composites 85 TamilMoliLoganathan,JesuarockiamNaveen,KoduriNagaGanapathi LakshmiReshwanth,KandasamyJayakrishna,andChandrasekar Muthukumar
5.1Introduction 85
5.2ThermalPropertiesofSisalFiber-ReinforcedPolymericComposites 87
5.3ThermalPropertiesofHybridSisalFiber/SyntheticFiber-Reinforced PolymericComposites 88
5.4ThermalPropertiesofSisal/OtherNaturalFiber-ReinforcedPolymeric Composites 89
5.5Conclusions 91 References 91
6ThermalPropertiesofFlaxFiberHybridComposites 93 CarloSantulli
6.1Introduction 93
6.2TechniquesforThermalAnalysisofNaturalFiberComposites 95
6.3GeneralPropertiesandCompositionofFlaxFibers 97
6.4ThermalAnalysisofFlaxFibers 98
6.5ThermalAnalysisofFlaxFiberComposites 99
6.6Conclusions 100 References 101
7ThermalPropertiesofthePineappleLeafFiber-BasedHybrid Composites 107 BheemappaSuresha,RajashekaraiahHemanth,andGurumurthyHemanth
7.1Introduction 107
7.2ThermalPropertiesofPolymers 108
7.2.1TheHypothesisofThermalConductivity 108
7.2.2FactorsInfluencingThermalConductivityofCompositeMaterials 109
7.2.2.1Fibers 109
7.2.2.2Resins 111
7.2.2.3Fillers 112
7.2.2.4Additives 112
7.2.2.5ThermalConductivityoftheComposites 113
7.3ImprovingtheThermalPropertiesofEpoxies 114
7.3.1ModificationofEpoxieswithOtherPolymersorAdditives 114
7.3.2ModificationofEpoxiesbyReinforcingFibers 115
7.3.3ModificationofEpoxiesbyMicron-sizedParticulateFillers 115
7.3.4ModificationofEpoxiesbyFillingNano-SizedParticulateFillers 116
7.3.5ModificationofEpoxiesbyHybridization 116
7.4TheThermalPropertiesofPALFComposites 116
7.4.1ThermogravimetricAnalysisofPALFComposites 116
7.4.2DynamicMechanicalAnalysisofPALFComposites 120
7.4.3DifferentialScanningCalorimetricAnalysisofPALFComposites 124
7.4.4ThermalConductivityofPALFComposites 126
7.5ConcludingRemarks 127
References 129
8ThermalPropertiesoftheGrass/CaneFiber-BasedHybrid Composites 135 ManickamRamesh,JaganathanManiraj,andSengottuveluRamesh
8.1Introduction 135
8.2HybridCompositeMaterials 137
8.3Cane/GrassFiberHybridComposites 138
8.4PropertiesofCane/GrassFiberHybridComposites 140
8.5ThermalProperties 140
8.5.1ThermalConductivity 141
8.5.2ThermogravimetricAnalysis 142
8.5.3DifferentialScanningCalorimetryAnalysis 142
8.5.4FlammabilityTest 142
8.5.5HeatDeflectionTemperatureTest 143
8.5.6SpecificHeatCapacityMeasurement 143
8.5.7ThermalDiffusivity 143
8.6ApplicationsofGrass/CaneHybridComposites 144
8.7Conclusion 145 References 145
9ThermalPropertiesoftheBananaFiber-BasedHybrid Composites 153
NasmiHerlinaSariandSenthilMuthuKumarThiagamani
9.1Introduction 153
9.2FabricationofBananaFiber-BasedHybridComposite 154
9.2.1HandLayup 154
9.2.2VacuumBag-AssistedResinInfusionTechnique 155
9.3ThermalPropertiesofBananaFiber-BasedComposites 155
9.3.1ThermalStability 155
9.3.2LimitingOxygenIndex(LOI) 155
9.3.3 ThermogravimetricAnalysis(TGA) 156
9.3.3.1JuteandBananaFiberHybridComposites 156
9.3.3.2GlassandBananaFiberHybridComposites 157
9.3.3.3Banana/Flax-BasedGlassFiberHybridComposite 158
9.4SpecificHeatofBananaFiberHybridComposites 159
9.4.1BananaandPineappleLeafFiberHybridComposites 159
9.5ThermalConductivityofBananaFiberHybridComposites 160
9.5.1ThePineappleLeafandBananaFiberHybridComposites 160
9.6ThermalDiffusivity 160
9.7Applications 162
9.8Conclusions 162 References 163
10ThermalPropertiesofKenafFiber-BasedHybrid Composites 167
ChinnaiyanDeepa,LakshminarasimhanRajeshkumar,andManickam Ramesh
10.1Introduction 167
10.2HybridComposites 168
10.3ThermalProperties 169
10.3.1ThermogravimetricAnalysis 169
10.3.2DynamicMechanicalAnalysis 172
10.3.3DerivativeThermogravimetricAnalysis 174
10.3.4DifferentialScanningCalorimetry 175
10.3.5ThermalMechanicalAnalysis 176
10.3.6FlammabilityTests 177
10.3.7HeatDeflectionTemperature 178
10.4Conclusion 178 References 179
11ThermalPropertiesofHempFiber-BasedHybrid Composites 183 HomNathDhakalandMohiniSain
11.1Introduction 183
11.2ThermalPropertiesMeasurementsandImportance 185
11.2.1ThermogravimetricAnalysis(TGA) 185
11.2.2HybridApproachforThermalPropertiesImprovement 186
11.2.3DifferentialScanningCalorimetry(DSC) 189
11.2.4ThermalConductivity 190
11.2.5LinearCoefficientofThermalExpansion 192
11.2.6DynamicMechanicalAnalysis(DMA) 193
11.3ConclusionsandPerspectives 197 References 198
12ThermalPropertiesofCelluloseNanofibersandTheir Composites 201 SadiaKhalid,TaniaAli,AsiyaGul,andSaraQaisar
12.1Introduction 201
12.2Nanocellulose 202
12.3CelluloseNanofibers(CNFs) 202
12.4CNFPreparation 203
12.5SurfaceFunctionalizationofCNFs 203
12.6CNF-BasedComposites 205
12.7ThermalPropertiesofCNFComposites 208
12.8CurrentStatus:CNF-BasedComposites 209
12.9OutlookandFuturePerspective 212 References 214
13InfluenceofGrapheneNanoparticlesonThermalPropertiesof theNaturalFiber-BasedHybridComposites 219 TheivasanthiThirugnanasambandan
13.1Introduction 219
13.2Graphene 220
13.3Polymer/GrapheneComposites 220
13.4Polymer/NaturalFiberComposites 223
13.5Polymer/NaturalFiber/GrapheneComposites 226
13.6Conclusion 233 Acknowledgments 233 References 233
14InfluenceofNanoclayontheThermalPropertiesofthe NaturalFiber-BasedHybridComposites 239 SabarishRadoor,JasilaKarayil,ReshmaSoman,AswathyJayakumar, EdayileveettilK.Radhakrishnan,JyotishkumarParameswaranpillai,and SuchartSiengchin
14.1Introduction 239
14.2EffectofNanoclayontheThermalStabilityofNaturalFiber-Based HybridComposites 240
14.3EffectofNanoclayontheInflammabilityofNaturalFiber-BasedHybrid Composites 244
14.4EffectofNanoclayontheMeltingandCrystallization(DSC)ofNatural Fiber-BasedHybridComposites 246
14.5EffectofNanoclayontheGlassTransitionTemperatureofNatural Fiber-BasedHybridComposites 247
14.6Conclusion 248 Acknowledgments 249 References 249
15EffectofCNTFillersonThermalPropertiesoftheBamboo Fiber-BasedHybridComposites 255 MohitHemath,BabuV.Hemath,HemathK.Govindarajulu,SanjayM. Rangappa,SuchartSiengchin,andSureshN.Sundaram
15.1Introduction 255
15.2MaterialsandMethods 257
15.2.1MaterialsUsed 257
15.2.2ExtractionofBambooMicrofibers 258
15.2.3AminoFunctionalizationofSWCNTs 258
15.2.4FabricationofSWCNT/BambooFiber(BF)/EpoxyHybrid Nanocomposites 258
15.2.5Characterization 259
15.2.5.1ThermalProperties 259
15.2.5.2FourierTransformInfrared(FTIR)Spectroscopy 259
15.2.5.3MechanicalPropertiesofSWCNT/BF/EpoxyComposites 259
15.2.5.4MorphologicalCharacteristics 260
15.3ResultsandDiscussion 260
15.3.1EffectonFTIRSpectra 260
15.3.2EffectonThermalDegradationProperties 260
15.3.3EffectonThermalConductivity 262
15.3.4EffectonMechanicalCharacteristics 264
15.3.4.1FlexuralandTensileProperties 264
15.3.5TensileFracture 265
15.3.5.1ImpactStrengthandHardness 266
15.4Conclusion 267 Acknowledgment 267 References 267
16EffectofMetalOxideFillersonThermalPropertiesofthe NaturalFiber-BasedHybridComposites 273 MohitHemath,HemathK.Govindarajulu,SanjayM.Rangappa,Suchart Siengchin,RubanRamalingam,andBabuV.Hemath
16.1Introduction 273
16.2MaterialsandMethods 274
16.2.1Materials 274
16.2.2ExtractionofBambooNanocelluloseFiber(BNF) 275
16.2.3FabricationofEpoxyHybridNanocomposites 275
16.2.4EpoxyHybridNanocompositeCharacterization 275
16.2.4.1ThermalProperties 275
16.2.4.2Flame-RetardantProperties 275
16.2.4.3MechanicalProperties 275
16.2.4.4MorphologicalProperties 276
16.2.4.5FourierTransformInfrared(FTIR)Spectra 276 16.3ResultsandDiscussion 276
16.3.1EffectonFTIRSpectra 276
16.3.2EffectonFlammability 277
16.3.3EffectonThermalStability 280
16.3.4EffectonMechanicalProperties 280
16.3.4.1TensileProperties 280
16.3.4.2TensileFracture 282
16.3.4.3FlexuralProperties 282
16.3.4.4CompressionProperties 283
16.3.4.5ImpactStrength 285
16.4Conclusion 286 References 286
17InfluenceofChemicalTreatmentsontheThermalProperties ofNaturalFiber-ReinforcedHybridComposites(NFRHC) 291 RafaeldeAvilaDelucisandJoséHumbertoS.AlmeidaJr
17.1Introduction 291
17.2ChemicalModificationsforNaturalFibersAppliedinHybrid Composites 295
17.2.1ChemicalTreatments 295
17.2.1.1ChemicallyTreatedNaturalFibersinHybridThermoset Composites 295
17.2.1.2ChemicallyTreatedFibersinHybridThermoplasticComposites 298
17.2.2ChemicalCouplingAgents 299
17.2.2.1MaleicAnhydride 299
17.2.2.2Silanization 300
17.2.3Two-StepTreatments 301
17.3ConcludingRemarks 302 References 303
18Physical,Mechanical,andThermalPropertiesof Fiber-ReinforcedHybridPolymerComposites 309 SubramanianRavichandran,SureshSagadevan,andMdEnamulHoque
18.1Introduction 309
18.2PreparationofCompositeMaterial 311
18.3CharacterizationofCompositeMaterial 312
18.3.1TensileTest 312
18.3.2FlexuralTest 312
18.3.3TestofWaterAbsorption 312
18.4ResultsandDiscussion 313
18.4.1MechanicalProperties 313
18.4.2WaterAbsorptionStudies 315
18.4.3ThermalProperties 316
18.5Conclusions 317
ConflictsofInterest 318 References 318
Index 321
Preface
Wearegladtopresentthebookentitled“NaturalFiber-ReinforcedComposites: ThermalPropertiesandApplications”tothermalanalysts,materialsscientists, materialsengineers,materialchemists,andresearchersworkinginthefieldof bio-composites.
Thisbookfocusesonexploringthethermalpropertiesofhybridcomposites reinforcedwithnaturalfibers.Asperliterature,thethermalpropertiesofthese compositescouldbeanalyzedbythetechniquessuchasdifferentialscanning calorimetry(DSC),thermomechanicalanalysis(TMA),thermogravimetricanalysis (TGA),anddynamicmechanicalanalysis(DMA).Inlieuofthis,allthechaptersare designedtocoverabroadaudiencewiththeaforementionedtechniquesonhybrid compositesreinforcedwithnaturalfibers.
Thisbookconsistsof18chaptersandisstructuredasfollows:Chapters1,2,and3 presenttheoverviewofthermalpropertiesofnaturalfiberreinforcedthermosetand thermoplastichybridcomposites.Chapters4to11discussthethermalpropertiesof hybridcompositesmadeupofdifferentnaturalfiberssuchassugarpalm,sisalfiber, flaxfiber,pineappleleaffiber,grass/canefiber,bananafiber,kenaffiberandhemp fiber.Chapters12to16provideinsightsontheeffectofnanofillers(e.g.graphene, nanoclay,CNT,metaloxide)onthermalpropertiesofnaturalfiberreinforced hybridcomposites.Chapter17discussestheeffectsofchemicaltreatmentsof hybridcompositesonthermalproperties.Chapter18providesanoverviewof physical,mechanical,andthermalpropertiesofhybridpolymercomposites.
Wethankourparentsandsincerelyappreciatethepublisher,thetypesetting professionalassociatedwiththisbook,andthankallthecontributingauthorsfor theirvaluabletimeandeffortsinsubmittingtheirworktothisbook.
ThermalCharacterizationoftheNaturalFiber-BasedHybrid Composites:AnOverview
ChandrasekarMuthukumar 1 ,SenthilkumarKrishnasamy 2,3 ,SenthilMuthu KumarThiagamani 3 ,RajiniNagarajan 3 ,andSuchartSiengchin 4
1 HindustanInstituteofTechnology&Science,DepartmentofAeronauticalEngineering,Kelambakkam, Chennai603103,Tamilnadu,India
2 KingMongkut’sUniversityofTechnologyNorthBangkok,CenterofInnovationinDesignandEngineering forManufacturing(CoI-DEM),1518WongsawangRoad,Bangsue,Bangkok10800,Thailand
3 KalasalingamAcademyofResearchandEducation,DepartmentofMechanicalEngineering,Krishnankoil 626126,TamilNadu,India
4 KingMongkut’sUniversityofTechnologyNorthBangkok,TheSirindhornInternationalThai-German GraduateSchoolofEngineering(TGGS),DepartmentofMaterialsandProductionEngineering,1518 WongsawangRoad,Bangsue,Bangkok10800,Thailand
1.1Introduction
Hybridcompositeisfabricatedbyaddingtwoormorefibersintoasinglepolymer system[1].Theresultingmaterialhasauniquefeaturethatcombinestheadvantages ofeachfiber.Sincedifferentfibersareaddedtogether,thebenefitsofoneparticulartypeoffiberpropertycouldbecompensatedwiththeotherfiberlackingaspecificproperty.Theperformanceofhybridcompositescouldbeinfluencedbymany factors[2–7]:
i.Fiberlength
ii.Fiberloading
iii.Fiberorientation
iv.Fiberlayersequence
v.Fiber/matrixinterfacialbonding
vi.Failurestrainoffiber
Thehybrideffectistermedasanapparentsynergisticimprovementofproperties duetodifferentfibersinasinglematrixsystem.Theselectionoffibersandtheir propertiesisofmainimportancetoachievetheenhancedpropertiesforthehybrid composites.Besidesthephysical,chemical,andmechanicalstabilitiesoffiber,the
NaturalFiber-ReinforcedComposites:ThermalPropertiesandApplications, FirstEdition. EditedbySenthilkumarKrishnasamy,SenthilMuthuKumarThiagamani, ChandrasekarMuthukumar,RajiniNagarajanandSuchartSiengchin. ©2022WILEY-VCHGmbH.Published2022byWILEY-VCHGmbH.
1ThermalCharacterizationoftheNaturalFiber-BasedHybridComposites:AnOverview matrixsystemalsodefinesthestrengthofthehybridcomposites.Thedifferenttypes ofhybridcompositesarecharacterizedasfollows[8–12]:
i.Towbytow:thefibersaremixeduprandomlyorregularly.
ii.Sandwichhybridcomposites:onematerialissandwichedbetweentwodifferent layers.
iii.Inter-plyorlaminated:twoormorefiberlayersarealternativelystackedregularly.
iv.Intimatelymixedfibers:varioustypesoffibersaremixeduprandomly.
Thoughthehybridcompositeshavemanyadvantages,theprimechallenges arereplacingthesyntheticfiber-reinforcedcompositesusingbiocomposites.Biocompositesexhibitfunctionalandstructuralstabilityduringstorageanddegrade upondisposalintotheenvironment.“Engineerednaturalfiber”isoneofthe excitingconceptstoobtaintheenhancedstrengthinthebiocomposites,which involvestheblendingoftheleafandstemfibers.Thecorrectblendingofthesetwo fibersexhibitsoptimumbalanceinmechanicalproperties,resultinginbalanced stiffness–toughnessproperties[13–15].
Themechanicalandphysicalcharacteristicsofthenaturalfiberareinfluenced bymanyfactors:(i)maturityoftheplantfiber,(ii)harvestingtimeandregion, (iii)soilcondition,(iv)rain,(v)sun,etc.Sincethenaturalfibersarenonabrasiveand hypoallergenic,theycouldbeprocessedefficiently.Amongstthevariousproperties ofnaturalfibers,thelowdensityandthecellularstructureallowthemtoexhibit betterthermalproperties.However,theamorphoushemicelluloseonthefiber surfacecanbeapotentialthreattothebetterinterfacialbondingbetweenthematrix andthefiber,therebyreducingtheproperties.Hence,themechanicalandthermal propertiesofthebiocompositescouldbefurtherenhancedthroughchemical treatments[16].Naturalfiberhascellulose,hemicellulose,andligninsusceptible todegradationonexposuretoelevatedtemperature[17–19].Thus,manystudies exploringthethermalpropertiesofthebiocompositeshavebeenpublishedoverthe years[20–22].Bybotanicaltype,thenaturalfibersareclassifiedintosixmajortypes (Table1.1).
Table1.1 Classificationofthenaturalfibers.
1.2ThermalCharacterization
Thethermalanalysesencompassafamilyoftechniquesthatwouldshareacommon feature,wherebyanymaterial’sresponsecouldbemeasuredthroughheatingor cooling.Thus,asignificantconnectionisheldbetweenthetemperatureandthe physicalpropertyofthematerials.Themostcommonthermaltechniquesthat havebeenusedbyresearchersandbyindustrialorganizationsforthermalcharacterizationarethermomechanicalanalysis(TMA),thermogravimetricanalysis (TGA),differentialscanningcalorimetry(DSC),anddynamicmechanicalanalysis (DMA).Thesetechniquesarenotonlyusedformeasuringthephysicalproperties withrespecttothetemperaturechangesbutalsousedinthefollowingareas:(i)to substantiatemechanicalpropertiesandthermalhistoryofthebiocomposites,(ii)to estimatetheservicelifeofcompositesindifferentenvironments,and(iii)asone ofthequalitycontrolapproachesinpolymersandtheirmanufacturingindustries. Figure1.1showssomeoftheessentialthermalanalysistechniquesandthe characteristicsmeasured[23–25].Intermsofresearch,thermalbehaviorofthebiocompositeshasbeeninvestigatedbyvaryingfibervolumefractions[26–28],varying fiberlayeringpatterns[29,30],usingdifferenttypesofchemicaltreatments[31,32], addingdifferentkindsoffillers[19,33,34],andusingpolymerblends[35,36].
Forinstance,Table1.2presentssomeoftheexperimentalworkscarriedouton thermalpropertiesusingdifferentnaturalfibers.
1.2.1DMA
Figure1.2presentsthestep-by-stepprocessinvolvedintheDMAofthepolymers andpolymer-basedcomposites.Outputparameterssuchasstoragemodulus(E′ or G′ ),lossmodulus(E′′ or G′′ ),anddampingfactor(tan �� )obtainedasthefunction oftemperatureareshowninFigure1.3a.Asthepolymerorcompositeisheated inthetemperaturerangewiththesimultaneousapplicationofoscillatoryload,it undergoesdisplacementorstrainwheresomeenergygetsstoredinthematerial, Thermal analysis techniques
Figure1.1 Variousthermalanalysistechniquesandtheirapplications.DFA,dielectric analysis.
1ThermalCharacterizationoftheNaturalFiber-BasedHybridComposites:AnOverview
Table1.2 Reportedthermalbasedworksofnaturalfiber-reinforcedhybridcomposites.
HybridcompositesDetailsofstudyReferences
Thermosetpolymers
Flax/sugarpalm/epoxyDMA[6]
Flax/wovenaloevera/epoxyTGA,DMA[20]
Sisal/cattail/polyesterThermalconductivity[37]
Datepalm/coirfiber/epoxyTGA[38]
Sisal/jute/sorghum/polyesterTGA[39]
Coir/Luffacylindrica/epoxyDMA[40]
Bamboo/kenaf/epoxyTGA,DMA,DSC[41]
Ramie/sisal/epoxySisal/curaua/epoxyTGA,DSC[42]
Flax/aloevera/hemp/epoxyTGA,DMA[43]
Kenaf/pineappleleaffiber/phenolicTGA[44]
Thermoplasticpolymers
Sugarpalm/roselle/polyurethaneTGA[45]
Jute/bamboo/polyethyleneDSC,TGA[46]
Sugarpalm/roselle/polyurethaneTGA[47]
Seaweed/sugarpalmfiber/thermoplasticsugar palmstarchagar TGA[48]
Coir/pineappleleaffiber/polylacticacid(PLA)TGA[49]
Coir/pineappleleaffiber/PLATGA,TMA[50]
Biodegradablepolymers
Sisal/hemp/bioepoxyDMA,TGA[29]
Kenaf/sisal/bioepoxyTGA,DSC,DMA[51]
Sisal/hemp/bioepoxyTGA[52]
whilesomeenergyisdissipatedasheatduetotheinternalfriction.Theresultant strainmeasuredbyapplyingtheoscillatoryloadisrepresentedaslossmodulus,storagemodulus,andphaseangleordampingfactor.Theabilityofthetestedmaterialto storetheenergyistermedasthestoragemoduluswhilethetendencyofthematerial todissipateheatenergyistermedasthelossmodulus.Storagemodulusrepresents thestiffnessofapolymerorcompositeandisoftenrelatedtoYoung’smodulus.Loss modulusisrelatedtothemolecularchainmotionssuchastransitionandrelaxation withinthepolymerduringtheheatingprocessandappliedload.Tan �� isadimensionlessnumberobtainedthroughtheratiooflossmodulustothestoragemodulus. Lowertan �� indicateshigherstiffnessandbetterinterfacialbondingbetweenfiber andpolymermatrix,whichrestrictsthemolecularmobilitywithinthepolymeric chains.
ASTM
standards
Input
D4440 Standard Test Method for Plastics: Dynamic Mechanical Properties Melt Rheology
D4473 Standard Test Method for Plastics: Dynamic Mechanical Properties: Cure Behavior
D5023 Standard Test Method for Plastics: Dynamic Mechanical Properties: In Flexure (Three-Point Bending)
D5024 Standard Test Method for Plastics: Dynamic Mechanical Properties: In Compression
D5026 Standard Test Method for Plastics: Dynamic Mechanical Properties: In Tension
D5279 Standard Test Method for Plastics: Dynamic Mechanical Properties: In Torsion
D5418 Standard Test Method for Plastics: Dynamic Mechanical Properties: In Flexure (Dual Cantilever Beam)
Specimen geometry
Frequency or strain
Type of load and clamping
Temperature program
Elastic Modulus vs. temperature
Viscous Modulus vs. temperature,
Damping Coefficient (tan ��) vs. temperature
Output
Assessment
Complex shear modulus in torsional mode
Glass transition temperature
Peak on loss modulus curve
Peak on tan �� curve
Peak on storage modulus curve
Figure1.2 Thermalcharacterizationsofthepolymerandpolymer-basedcomposite throughDMA,step-by-stepprocess.
Polymersareviscoelasticandcanbeclassifiedintocrystalline,amorphous, andsemicrystalline(hasbothcrystallineandamorphouscharacteristics)dependinguponthecomposition.Itisbecauseofthischaracteristicthatpolymersor polymer-basedcompositeundergoesphasechangeduringthesimultaneousapplicationoftheloadandheatingprocess(Figure1.3b).Figure1.3ashowsthetypical dataobtainedfromDMA.Glasstransitiontemperature(T g )isthetangentobtained inthephasechangeregionbetweenglassystateandrubberystate. T g canbebelow themeltingtemperatureforapolymer,whichhasbothcrystallineandamorphous characteristics.Thematerialtendstogetsofterratherthanmeltingat T g .DMAis particularlyusefulinidentifyingthecross-linkingdensityofthepolymer,asshown inFigure1.3b.Itcanbenoticedthatpolymerswithahighcross-linkingdensity havehigher T g andgreaterlossmodulusandstoragemodulus,whileitisviceversa forpolymerswithlowcross-linkingdensity[53].
1.2.2TMA
TMAisacommontechniqueusedforinvestigatingthedimensionalchangeofmaterialunderthecombinationoftemperatureandafixedload.Figure1.4presents thestep-by-stepprocessinvolvedintheTMAofthepolymersandpolymer-based composites.Dimensionalchangeofmaterial(atnanoscale)undertheinfluenceof temperatureandloadcanbemeasuredinvarioustestingmodesshowninFigure1.5. Changesinthefreevolumeofmaterialdependingupontheheatabsorptionorheat releasewithrespecttothetemperaturecanalsobedeterminedwiththistechnique. Figure1.6a–cshowsthatthe T g measurementforapolymerorapolymercompositecanbederivedfromtheTMA,DSC,andDMA.
Figure1.3 Thermalcharacterizationofpolymerandpolymer-basedcompositewithDMA. (a)Typicalcurve.(b)Viscoelasticcharacteristicsofthepolymer.Source:Sabaetal.[53].
1.2.3DSC
Figure1.7presentsthestep-by-stepprocessinvolvedintheDSCofthepolymers andpolymer-basedcomposites.InDSC,thesampleisheatedaround30totheelevatedtemperaturebeyond300 ∘ Cwiththeconstantsupplyofliquidnitrogenina controlledchamber.Heatflowfromthesampleismeasuredasafunctionofthe temperatureshowninFigure1.8.Thechangesincrystallineproperties(T g ),melting temperature(T m ),andcoldcrystallizationtemperature(T c )duetotheintroduction oftwoormorenaturalfibersinthehybridcompositecanbeevaluated.
1.2.4TGA
Figure1.9presentsthestep-by-stepprocessinvolvedintheTGAofthepolymers andpolymer-basedcomposites.Itisaneffectivetechniqueforevaluatingthermal
D696 Standard Test Method for Coefficient of Linear Thermal Expansion of Plastics Between –30 and 30 °C with a Vitreous Silica Dilatometer
E831-19 Standard Test Method for Linear Thermal Expansion of Solid Materials by Thermomechanical Analysis
Specimen preparation
Type of load
Heating rate
Start/end temperature
Change in dimension vs. temperature
Volumetric change vs. temperature
Coefficient of linear thermal expansion
Free volume
Glass transition temperature
Shear modulus
Young’s modulus
Creep
Flexural stress
Softening point and heat deflection temperature
Figure1.4 Thermalcharacterizationsofthepolymerandpolymer-basedcomposite throughTMA,step-by-stepprocess.
Figure1.5 TestmodesinTMA.Source:SabaandJawaid[54].
decompositioncharacteristicsofthepolymersandpolymercompositereinforced withthenaturalfibersorthesyntheticfibers.Itprovidesthequantitativemass changeofthesampleduetotheheatingunderthecontrolledatmosphere.Anatural fiberobtainedfromtheplantsandtreesismadeupoftheconstituentssuchascellulose,hemicellulose,lignin,pectin,wax,moisture,andash.Thepercentageofconstituentscanvaryfromonefibertoanother,whichhasasignificantinfluenceonthe thermaldecompositioncharacteristicsofnaturalfiberandtheircomposites.Also, thesefiberconstituentsarevolatileandcandecomposeatelevatedtemperatures.
8 1ThermalCharacterizationoftheNaturalFiber-BasedHybridComposites:AnOverview
Figure1.6 T g measuredfromthevariousthermalcharacterizationtechniques:(a)TMA,(b) DSC,and(c)DMA.Source:SabaandJawaid[54].
D3418-15 Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry
E1269-05 Standard Test Method for Determining Specific Heat Capacity by Differential Scanning Calorimetry
Specimen preparation Specimen weight Purge gas and gas flow rate Heating rate Start/end temperature
vs.
Figure1.7 Thermalcharacterizationsofthepolymerandpolymer-basedcomposite throughDSC,step-by-stepprocess.
AfewmilligramofsampleisplacedintheTGAchamberandheatedfromroom temperaturetoashighas700 ∘ Catadefinedramprateinthepresenceofnitrogento preventoxidationinsidethechamber.Thethermalstabilityofapolymer-basedcompositeisusuallyassessedfromthethermogram(TGcurve)andthederivativethermogram(DTGcurve)obtainedfromtheTGA,asshowninFigure1.10.Parameters
Figure1.8 ThermogramfromtheDSC.Source:Chandrasekaretal.[55].
ASTM
•
D2288 Test Method for Weight Loss of Plasticizers on Heating
D4202 Test Method for Thermal Stability of PVC Resin
D2115 Test Method for Volatile Matter (including water) of Vinyl Chloride Resins
D2126 Test Method for Response of Rigid Cellular Plastics to Thermal and Humid Aging
D3045 Recommended Practice for Heat Aging of Plastics Without Load
D1870 Practice for Elevated Temperature Aging Using a Tubular Oven
D4218 Test Method for Determination of Carbon Black Content in Polyethylene Compounds by a Muffle-Furnace
D1603 Test Method for Carbon Black in Olefin Plastics
D5510 Practice for Heat Aging of Oxidatively Degradable Plastics
E1131 Standard Test Method for Compositional Analysis by TGA
E1641 Standard Test Method for Decomposition Kinetics by TGA
Specimen preparation
Specimen weight
Purge gas and flow rate
Heating rate
Weight % vs. Temperature
Derivative weight % vs. Temperature,
Residue %
Onset temperature
Inflection temperature
Endset temperature
Filler content
Figure1.9 Thermalcharacterizationsofpolymerandpolymer-basedcompositesthrough TGA,step-by-stepprocess.
suchastheonset,endset,inflectiontemperature,andresiduepercentageattheend oftheheatingprocessintheTGAchamberareusuallycomparedtoidentifychanges duetothereinforcementpercentageandtypeoffiber.Degradationtemperature at5%,10%,20%,40%,and80%weightlossalongwiththeresiduecanalsobe discussed.
Inthecaseofapolymer,thermaldecompositionusuallyoccursinsinglestage, whereas,forthenaturalfiber,thermaldecompositionoccursintwoorthreestages
1ThermalCharacterizationoftheNaturalFiber-BasedHybridComposites:AnOverview
Figure1.10 AtypicalTGAcurveofthehybridcompositewithkenafandbamboofibers. (a)Thermogram.(b)Derivativethermogram.Source:Cheeetal.[41].
dependingonthefiberconstituents.Initialmasslossbetween50and150 ∘ Cisdue totheevaporationofmoistureinthefiber.Theweightlossatatemperaturerange between150and300 ∘ Cisassociatedwiththedecompositionofhemicelluloseand lignin.Thefinalweightlossbetween300and700 ∘ Cisattributedtothedecompositionofcellulose.Sincethefiberconstituentsvaryfromonefibertoanother,TGA hasprovedtobeanexcellenttoolfordeterminingthechangesinthermaldecompositioncharacteristicsofthehybridpolymercompositereinforcedwithtwoormore naturalfibers.Thermalstabilityisalsoevaluatedbyresiduepercentageattheendof theheatingprocess.Thehighertheresidues,thebetterthethermalstabilityofthe composite.
1.3Conclusion
Thermalcharacterizationofthehybridcompositesusingvariouscommercially availabletechniquessuchasDMA,TMA,DSC,andTGAhasbeendiscussed.The followingaretheconclusions:
● DMAisusefulindeterminingthecreeppropertiesandinterfacialinteractionsof thecompositesandmeasuringtheirstiffness,materialbehaviorwithrespectto thephasetransitions,damping,andrelaxationprocessesinarangeoffrequencies andtemperatures.
● TMAhelpsindefiningthematerialstructurewithrespecttothedimensional andvolumetricchange,surfaceroughness,molecularstructure,cure,and cross-linkingpolymerizationunderbothstaticanddynamicloads.
● DSCisconsideredasoneoftheprimarytoolsforthermodynamicanalysisand curekinetics.Itgivesusefulinformationonthephasetransitionsuponheating andquantifiestheglasstransitiontemperature,meltingtemperature,andcrystallizationtemperaturerelatedtothepolymersandpolymer-basedbiocomposites.
● TGAhasbeenwidelyusedtoillustratethethermalstabilityofthecomposites, whichprovidesthequantitativemasschangeofthesampleduetoheating.Italso providesvitalinformationonthedecompositioncharacteristicsoftheconstituents ofthecompositesatelevatedtemperatures.
Theforthcomingchaptersofthisbookwouldgiveextensiveinformationonthe above-discussedthermalcharacterizationtechniqueswithrespecttodifferentnaturalfibersandpolymerstargetedforvariousapplications.
Acknowledgment
ThisstudywasfinanciallysupportedbytheKingMongkut’sUniversityofTechnologyNorthBangkok(KMUTNB),Thailand,throughgrantno.KMUTNB-BasicR64-16andthroughgrantno.KMUTNB-64-KNOW-07.
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ThermalPropertiesofHybridNaturalFiber-Reinforced ThermoplasticComposites
A.Vinod,YashasGowda,SenthilkumarKrishnasamy,M.RSanjay,andSuchart Siengchin
NaturalCompositesResearchGroupLab,TheSirindhornInternationalThai-GermanGraduateSchoolof Engineering(TGGS),KingMongkut’sUniversityofTechnologyNorthBangkok,1518Pracharat1road, Wongsawang,Bangsue,Bangkok,10800,Thailand
2.1Introduction
Theprolongeduseofsyntheticmaterialsiscausingharmfuleffectsontheenvironmentthroughproductionanddisposal.Theadventofhazardsontheenvironment hasinfluencedmanyindustrialistsandresearcherstoadoptecofriendlymaterials likenaturalfibersasreinforcementsinthermoplasticpolymercomposites.Over thepastfewdecades,duetotheindustrialrevolution,manynaturalfiberslikejute, sisal,andhempareusedtodevelopcomponentsintheautomotive,household, andcivilconstructions.Thisextensiveuseofnaturalresourceshascreateda demandandanurgetoidentifynewpotentialresources[1–5].Inthisregard,many newnaturalfiberslike Tridaxprocumbens,Saccharumbengalense,Parthenium hysterophorus, and Catharanthusroseus areidentifiedaspotentialreinforcements inpolymermatrices[6–9].Theplantfibersareconsideredasbetterreinforcements duetotheirremarkablepropertieslikelowdensity,biodegradability,availability, andprocessability.Plantfiber-reinforcedlightweightstructuresinautomobiles improveditsperformancebyimprovingthefueleconomyandreducingthelandfill ondisposal.Thenaturalfibershaveothergoodpropertieslikeexcellentelectrical, thermal,andacousticinsulationproperties[9–11].
Despitetheiradvantages,therearecertaindeficiencieslikelowerstiffness,lower thermalstability,strengthdegradationwithrespecttotime,watersensitivity,lower impactresistance,andeasilypronetobacterialandfungalattacks.Inmanycases,a singletypeofreinforcementcannotofferthedesirablepropertiesrequiredforthe application.Toovercometheissue,hybridcompositesaredeveloped,whichisa combinationoftwoormorematerialslikenatural–naturalornatural–synthetic[12]. Thereinforcementsinhybridthermoplasticpolymercompositemaybeintheform offillers,mats,orfibers.Thehybridizationofnaturalfibercompositesprovidesan optionforachievingablendofhighstrengthtoweightratio,goodthermalstability,
NaturalFiber-ReinforcedComposites:ThermalPropertiesandApplications, FirstEdition. EditedbySenthilkumarKrishnasamy,SenthilMuthuKumarThiagamani, ChandrasekarMuthukumar,RajiniNagarajanandSuchartSiengchin. ©2022WILEY-VCHGmbH.Published2022byWILEY-VCHGmbH.
2ThermalPropertiesofHybridNaturalFiber-ReinforcedThermoplasticComposites
anddurablecomponentswhencomparedtoasingletypeofreinforcements.This approachofhybridizationmainlyhelpsinachievingcost-effectivenessandreduces theuseofsyntheticmaterialswhichpollutestheenvironment[13].
Thethermalbehaviorofthecompositeisavitalpropertythatdefinesthefunctionalityofthematerialsintemperature-sensitiveenvironments.Applicationsof compositesinautomobiles,aerospace,andindustrialinsulationaremostlyprone totemperaturefluctuation.Itisessentialtostudythethermalaspectsofthehybrid compositetodevelopamoresustainableanddurablematerialthatissuitablefor commercialization[14].Varioustechniquesinvolvingthethermalstudyofnatural fiberhybridcompositesarediscussedintheforthcomingsections2.2.1to2.2.4.
2.2ThermalProperties
Thermalpropertieslikethermalstability,glasstransitiontemperature(T g ),storage modulus(E′ ),lossmodulus(E′′ ),andmeltflowpropertiesofcomposites,mustbe evaluatedbeforeusinginversatiletemperature-fluctuatingapplications[15,16]. Thesepropertieshelptotailorthepropertiesofthermoplasticpolymercomposites toenhancetheirthermalaspectsforsuitabilityandsustainabilityintheapplication.Currently,therearevariousthermoplasticpolymerslikepolypropylene (PP),polyethylene(PE),polystyrene(PS),polylacticacid(PLA),polyamide,and polyhydroxyalkonates(PHA),whicharecommonlyusedasamatrixinnatural fiberhybridcomposites[17,18].Thermoplasticpolymersareverymuchsensitive totemperature,whichresultsinphasetransitioninelevatedtemperatures.The phasetransitiontemperaturesofthethermoplasticpolymerscanbealteredby reinforcingthemwithvariousnaturalfibersorwiththecombinationofnaturaland syntheticfibers.Thesekindsofreinforcementblocktheheatflowandrestrictthe polymerchainmovementbyelevatingtheglasstransitiontemperature(T g ),which subsequentlyraisesthetemperature-withstandingability.Thesereinforcements playavitalroleincontrollingcertainfactorssuchasheatdiffusion,thermal insulationcapacity,meltflow,phasetransitiontemperature,etc.Hence,itisvery crucialtostudythethermalpropertiesofcomposites.Adetailedsurveyaboutthe thermalpropertiesofhybridnaturalfiber-basedthermoplasticcompositesisgiven intheforthcomingsections2.2.1to2.2.4.Thecurrentworkwillbeverybeneficial fortheresearchers,industries,scientists,andacademicianstoknowaboutthe recentadvancesintestingprocedures,characterizationprinciples,andthermal propertiesofrecentlyidentifiedhybridthermoplasticcomposites.
2.2.1ThermogravimetricAnalysis(TGA)
TGAanalysisisperformedtomeasuretherateofchangeinmasswithafunctionof temperatureandtimeinacontrolledenvironmentandtopredictthethermalstabilityandthecompositionofthecomposite.InstrumentslikeMettlerToledo(Model: TGA2SF)andPerkinElmer(Model:TGA8000N5320011,N5320010,TGA4000system)arecommonlyusedtoperformtheanalysis[19].Asampleof5mgisplacedin
0/40 SP/G 10/30 SP/G 20/20 SP/G 30/10 SP/G
Figure2.1 (a)TGAsugarpalm/glassfibercomposite(b)DTGSugarpalm/glassfiber composite.Source:Atiqahetal.[21].
analuminumcruciblewithinafurnace.Thetestiscarriedoutinacontrolledenvironmentataheatingrateof10 ∘ Cmin 1 withintherangeof30–1000 ∘ Cdepending uponthecomposite’scomposition.Theresultingthermogramisthegraphicalrepresentationoftemperaturevs.mass,whichprovidesinformationaboutthermalstability,compositionsofinitialsamples,andtheintermediatecompoundsformedduring heating.Theseresultfromphysicalphenomenalikephasetransitions,absorption anddesorption,solid–gasreactions,anddecompositionwithrespecttotemperature. TheTGAanalysisalsoprovidesderivativethermogravimetrycharts(DTG),which isthefirstderivativeofthermogravimetry.Furthermore,ithelpsintheinvestigation ofreactionkinetics,appliedkinetics,oxidativedegradation,andoxidativestability [20].ThehighestpeakoftheDTGcurveatanytemperaturegivestherateoflossin mass.Incaseofoverlappingreactions,therearedifficultiesinpredictingtheinitial andfinaldegradationtemperaturesusingTGcurves,whiletheDTGcurvesprovide preciseinformationoninitialandfinaldegradationtemperatures.AmodelTGAand DTGresultsarepresentedinFigure2.1.
Figure2.1a,bshowsthethermogravimetryresultsofsugarpalm/glassfiberreinforcedthermoplasticpolyurethanehybridcomposites.DTGcurvesfrom Figure2.1bshowthattheincreasedadditionofSPF(30/10SPF/GF)totheTPU matrixincreasedtheweightlossattemperature T max 435 ∘ C.Furthermore,it reducedthedecompositiontemperatureoftheTPUhybridcomposites.ItisconcludedthatthereductioninGFandincreaseintheSPFdidnotaffectthethermal stabilityofcomposites[21].Asimilarbehaviorisobservedinjute–glassepoxy thermosetcomposites[22].Whenglassfibersarehybridizedwithbamboofibersin thepolypropylenematrix,theresultingthermogramsrevealanincreaseinthermal stabilityfor15%bamboofiber/15%glassfiber/2%maleicanhydridecouplingagent, duetoincreasedbondingandthehigherthermalstabilityofglassfibers[23]. Variousstudiesshowedthatthehybridizationofsyntheticfiberswithnaturalfibers providesdesirablethermalstability,andtheuseofsyntheticmaterialsisreduced bythesubstitutionofnaturalfibers.Moreover,theresultingthermalpropertiesare comparablewiththoseofsyntheticreinforcements.Similarly,whenglassfibers andshorthempfibersarehybridizedinpolypropylene,theTGAresultsrevealan
