Polymeric additives for improving the flow properties and viscosity index of lubricating oils

Four sets of copolymeric additives were synthesized via copolymerization of dialkyl fumarates and dialkyl maleates with vinyl acetate (VAc) and vinylp yrrolidone (VP) monomers. The dialkyl esters were prepared by the esterific ation of maleic and fumaric acids with a series of n-alkanol having an incr easing number of carbon atoms to produce two groups of diesters. The comple tion of the esterification reaction was confirmed by spectroscopic analysis . The molecular weights of the prepared esters and copolymers were determin ed and the influences of different parameters on the molecular weight of th e produced copolymers were discussed. The efficiency of the prepared copoly mers as viscosity index and flow improvers (pour point depressants) was inv estigated. It has been found that the dialkyl ester/VP copolymers are more efficient as viscosity index improvers than the dialkyl ester/VAc copolymer s. On the other hand, it has been found that the copolymers based on didode cyl fumarate/VAc are the most effective pour point depressants.