Evaluation of poly alkyl methacrylates as Viscosity Index Improvers

Viscosity index improvers (VIIs) are high molecular weight, oil soluble polymers which ideally increase the viscosity of lube oil at applicable temperature range. Generally polymersthat use to improve viscosity index (VI) are classified as: i) olefin polymers and copolymers (OCP) ii) acrylate polymersand copolymers (PMAs) [1]. The performance of VIIs depends on the behavior of the polymer chains in the oil solution. PMAs are rather stable materials and do not normallyundergo chemical reactions under moderate to even relatively severe conditions [2-3]. In the present work, PMAs with different alkyl chain lengthwere synthesized and the changes of VI oil solutions against polymer concentration were investigated