Thermal oxidation behaviour of synthetic oils: Basic studies in the polymerization of polyol ester oils

Abstract

The oxidation behaviour of synthetic oils has been extensively studied during recent decades, and there is general agreement on both the mechanism and products of the oxidative degradation of oils. However, the other phenomenon of oil ageing, polymerization has been little studied. These polymers are responsible for the increase of viscosity, production of sludge and the formation of deposits. In the investigation reported here, oligomers have been isolated and studied at an early ageing stage. The dependence of viscosity on the degree of polymerization is demonstrated. A polymerization mechanism and a monomer for polyolester oils are proposed and discussed.