Design And Application Of Two Series Of Asymmetric Nickel And Copper Schiff-base Catalysts For Olefin Polymerization

Design of defferent catalysts is the core of polymerization technology to promote the prosperity of polyolfin industry. Among them, the late transition metal catalysts for olefin polymerization remain superior, which is currently a hot research. This thesis focuses on the study of two series of asymetric Ni、Cu Schiff-base catalysts for olefin polymerization, especially by checking of reaction procedure and catalytic structure.As to the obtained12new asymmetric Schiff-base catalysts, they were well characterized by modern analytic methods, and the catalytic polymerization performance on nonpolar monomer styrene in activation with MAO was checked. The results showed that two series of asymetric Ni、Cu Schiff-base catalysts could effectively catalyze the controllable polymerization besides affording isotactic-rich aPS (48-50%). Among them, for the Ni catalysts, under the optimal condition, the catalytic activity is between4.02to8.15×105g·mol-1h-1, the Mn of the Polystyrene between0.964to1.157×104g.mol-1and PDI between1.77to1.97, respectively. In contrast, among the Cu catalysts, the acticity range is1.72to2.56×105g·mol-1h-1and the Mn of the Polystyrene between0.326to10.767×104g.mol-1, while the PDI between1.16to1.56endowed the relatively controllable polymerization.In addition, using the Cl-OP-Ni/MAO system with relatively higher activity as the catalysts, their catalytic polymerization behaviors of methyl methacrylate were also studied in detail. The results showed that these6catalysts could catalyze the effective polymerization of MMA, affording isotactic-rich aPMMA (PMMA=polymethyl methacrylate). From which, the catalytic activity is between the range of6.756to12.506×104g·mol-1h-1,the Mn of the aPMMA with1.051to3.877×104g·mol-1,and PDI with1.16to1.56. Finally, through exploring on the relationship between the catalyst structure and the polymerization performance, the study also showed that both steric and electronic effects of two series of asymetric Ni、Cu Schiff-base catalysts were important and influential to catalytic activity.