Synthesis of poly n– octyl methacrylate and its copolymers with styrene as viscosity index improvers

Viscosity index improvers are long chain, high molecular weight polymers that function by increasing the relative viscosity of an oil more at high temperatures than they do atlow temperatures [1].The viscosity index (VI) of oil depends on the behavior of the polymer molecules in the oil such aspolymer solubility, molecular weight, concentration, and resistance to shear degradation [2]. Polymers based on alkyl methacrylates are widely used as viscosity thickeners, andviscosity index improvers [3]. In the present work a new copolymer of octylmethacrylate with different weight percent of styrene was synthesized and evaluated as viscosity index improvers for lube oil