Degradation of polyisobutylene dissolved in mineral oil

Abstract

1. It has been shown that the regularities in the mechanical degradation of high polymer additives in a pinion reducing gear are qualitatively similar to those which are observed in different types of laboratory test equipment. The final viscosity of a solution of the polymer in oil after it has been used in a reducing gear (independently of the original viscosity) is higher the lower the molecular weight and the concentration of the polymer. 2. Analytical equations have been derived on the basis of a mathematical analysis of the experimental data obtained for calculating the mechanical degradation of polyisobutylene in solution in mineral oil when the thickened oil is used in pinion reducing gears. Two variables — either the concentration and the molecular weight of the polymer or the initial viscosity of the solution and the molecular weight of the polymer — are involved in using these equations for calculation. 3. The equations which have been suggested are suitable for calculating the mechanical degradation of polymers when they are used as additives for oils used in different designs of pinion reducing gears.