Alkyl methacrylate: ɑ-Olefin copolymers as viscosity modifier additives in lubricants

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">The potential for use of copolymers of iso-decyl methacrylate and 1-decene as viscosity modifying additives in lubricant compositions has been investigated. Three copolymers were prepared by free-radical initiated polymerization in toluene solvent, using AIBN as initiator and employing different levels of 1decene (10-40 wt %) in the monomer mixture. The copolymers were characterized employing GPC, DSC/TGA, FTIR and NMR techniques for determining the thermal characteristics, average molecular weights <i>(M_w </i>and <i>M_n), </i>and copolymer composition. The composition of the copolymers with respect to relative proportion of two monomers was determined by two independent methods described in literature based on FTIR and Proton NMR spectroscopy. The level of incorporation of 1-decene monomer in the copolymers as determined by these methods was only of the order of 7-13%, while literature reports suggest scope for incorporating upto 12-15% a-olefin under free-radical polymerization conditions. The resulting copolymers were evaluated for potential use as viscosity modifiers in lubricant compositions through viscometric and bench screen tests, in comparison to a normal poly (alkyl methacrylate) (PMA). The results demonstrated a moderate improvement in the performance of one of the experimental copolymers as compared to standard PMA in certain respects.</span>