Preparation And Application Of Hydrogenated SIBR Used For Viscosity Index Improver

The Styrene-Isoprene-Butadiene ternary random copolymer SIBR was synthesized using the anionic polymerization method with n-butyllithium,tetrahydrofuran as the initiator and structure modifiers respectively.A series of molecular Weight controllable and Narrow molecular weight distribution SIBR were obtained by Molecular design methods and anionic polymerization techniques.The 1,2 microstructure in polybutadiene segment and 3,4 microstructure in polyisoprene segment of SIBR was regulated by Tetrahydrofuran-conditioning system.FT-IR,¹H-NMR and GPC were used to evaluate the molecular weight and Microstructure of SIBR,Proved that the polymer was of molecular weight controllabe and microstructure adjustable.The SIBR was hydrogenated with the nickel naphthenate(Ni)/triisobutyl aluminum(Al) catalyst system.The influence of hydrotreating technology on the hydrogenation degree of SIBR was studied in this paper,concretely speaking,it includes temperature,pressure,time, catalyst dosage,Al/Ni and monomer content,the optimum reaction conditions was determined.It was found that,the nickel naphthenate(Ni)/triisobutyl aluminum(Al) catalyst system had a higher activity and selectivity.When the temperature was 60℃,hydrogen pressure was 4MPa,catalyst amount was 2mg/g dry gel,Ai/Ni was 7,reaction time was 3 hour,the hydrogenation degree of SIBR could reach to 98%,exhibiting a good hydrogenation results.furthermore,the kinetics of hydrogenation reation of SIBR under different temperature and hydrogenation reation rate of microstructure was were investigated.It was found that,the hydrogenation reation rate of Polybutadiene segment was quicker than that of Polyisoprene segment(B＞I),the hydrogenation reation rate of microstructure from big to small was B_1,2＞B_1,4＞I_3,4＞I_1,4;B＞I respectively.Many kinds of methods were used to study the molecular weight and molecular weight distribution,microstructure,thermal property of the SIBR before and after hydrogenation.Also,the hydrogenation degree was measured using nuclear magnetic method,infrared method,bromine-iodometric technique.The hydrogenated SIBR can be used as viscosity index improvers in oil,the relationship of structure and performance of hydrogenated SIBR was studied.The effect of molecular weight,microstructure and polybutadiene content of the SIBR on viscosity index improvers was investigated in details.The main performance of viscosity index improvers includes thickening efficiency,shearing stability,high temperature high shear resistance and low temperature performance.It was found that,hydrogenated SIBR was an excellent viscosity index improvers with outstanding shearing stability and low temperature performance.