Evaluation of oxidation-mediated volatility of hydrocarbon lubricant base fluids

Abstract

Lubricant base fluids exhibit differences in volatility based on their molecular structures and the distribution of components. We report work to evaluate the volatilization of hydrocarbon base fluids using thermogravimetric analysis (TGA) and gas chromatographic simulated distillation. Commercial base fluids, including samples from API groups II, III, IV, have been evaluated. Kinematic viscosity was not a good predictor for volatility when all lubricants were considered. Polyalphaolefin (group IV) base fluids were found to have lower volatility than isoviscous group II and group III chemically modified mineral oil base fluids as measured by TGA, simulated distillation and Noack techniques. The advantages of TGA for measurement of lubricant volatility are discussed. Copyright © 2006 John Wiley & Sons, Ltd.