Flow Activation Quantities of VI-improver-blended Mineral Lubricating Oils

Abstract

The flow activation quantities were experimentally determined at 25.0°C with mineral lubricating oils blended with various concentrations of VI-improver. While polylauryl-methacrylate increases activation volume substantially and decreases activation entropy considerably, it does not affect activation enthalpy. Polyisobutylene changes the quantities only slightly. Molecular interpretation of these observations has been attempted.