Synthesis Of Polymethacrylate Viscosity Index Improver For Lubricanting Oil And Studies On Its Lubricating Properties

Most base oils have poor viscosity-temperature performance due to some defects of their structures.In order to solve this problem,people often add viscosity index improvers(VIIS)to lubricating oils,which is the most effective and relatively low cost method.Some changes may be made to the lubricating properties of the base oil after the addition of VIIs.It is worth noting that current researches focus on the formulation improvement and the conventional performance characterization of the VII.There is few systematic and in-depth research on the characteristics of the lubricating oil film of oils containing the VII under non-conformal and conformal contact.In this thesis,the synthesis and tribological properties of viscosity index improver of polymethacrylate were studied.The thesis mainly includes the following four aspects: synthesis,characterization and performance evaluation of alkyl methacrylate and polymethacrylate;the measurement of the characteristics of lubricating oil film of oils containing VII under non-conformal contact;the measurement of friction and wear of oils containing VII;the measurement of the characteristics of lubricating oil film of oils containing VII under conformal contact.Firstly,the esterification of methacrylic acid and isomeric dodecyl alcohol was carried out and the product was characterized.In addition,a series of compounds polymethacrylate and dispersed polymethacrylate were synthesized,and the effects of composition changes and polymerization processes on the performance of polymers were investigated.Afterwards,the film thickness and friction of oils containing VII under the condition of pure sliding and variable silding-rolling ratio were measured by using the test meter of lubricant film thickness and frictional force under non-conformal contact.The effects of the average carbon number of the alkyl side-chain,side-chain isomerization,the type of hetero atom and molecular weight on the measurement results were analyzed.At the same time,PAO10 that is similar in the viscosity of oils containing VII and base oil 150 N were measured and compared with the measurement results of oils containing VII.Subsequently,the friction and wear characteristics of oils containing VII at 40℃ and 100℃ were measured by the four-ball module of the MMW-1 vertical universal friction and wear tester,and compared with the base oil.Finally,the film thickness and friction of a part of oils containing VII under the parallel gap formed by the ceramic step slider and the glass disk were measured by using the test meter of lubricant film thickness and frictional force under conformal contact.At the same time,the film thickness of some oils containing VII under the tilt slider-disc contact was also measured,and compared with the predicted value of the oil film thickness formula constructed by the author based on PAO lubricating oil.The related research content of this paper provides reference for the synthesis of viscosity index improver of polymethacrylate.At the same time,studies on the lubricating characteristics of viscosity index improver of polymethacrylate are futher enriched and improved.