Water-Soluble Thickeners for Industrial Lubrication Erik Willett, PhD; Daniel Vargo; David DeVore Functional Products Inc.* Macedonia, OH USA Abstract Water-based synthetic and biobased polymers have potential to modify the viscosity of water. Renewable and/or biodegradable water-soluble polymers may be appropriate for use in environmentally acceptable lubricants (EALs) for applications in forestry, maritime, oil exploration, and other industries. This study evaluated synthetic and biobased polymers for possible use as viscosity modifiers or viscosity index improvers for water-based lubricants. Synthetic polymers (polyalkylene glycol, polyether, polyacetamide, polyacrylamide, and polyalcoholester) offered the best VI improvement but had varying levels of biodegradability; moderate treat rates met viscosity specifications for ISO 46 and 460 formulations. Biobased polymers (linear, branched, and modified polysaccharides) tended to require extra processing; some very high molecular weight products showed excellent thickening efficiency and biodegradability. Hydrogen bonding behavior provided explanations for observations of solubility, phase separation, and foaming. Several water-soluble additives were evaluated at 0.5 wt% for anti-wear, extreme pressure, and ferrous corrosion prevention performance in an ISO 46 base formulation of polyether in water. Future studies will focus on measuring polymer shear stabilities and identifying more additives for anti-wear, extreme pressure, and corrosion inhibition for the ultimate development of fully-formulated waterbased industrial lubricants. 1. Introduction to Aqueous Chemistries for Lubricants Depending on the end-use application, water can be an essential component or an undesirable contaminant in industrial lubricants and greases.[1] [2] Water is an integral part of many metalworking fluids, fire resistant hydraulic fluids, and glycol coolants.[3] [4] These aqueous systems utilize water as a cost-effective medium that can help reduce fire hazards and provide excellent cooling, and high lubricity when properly formulated.[5] Environmentally Acceptable Lubricants Environmentally acceptable lubricant (EAL) programs such as the European Ecolabel specify the use of biodegradable and renewable lubricants for maritime and forestry applications .[6] [7] Many of these products are formulated from base oils such as plant or animal triglycerides and synthetic esters of such fatty acids, which biodegrade naturally, Figure 1.
Figure 1. EALs formulated from renewable base stocks can biodegrade in water or soil - 44 VOLUME 83, NUMBER 4
