Abstract:

Ni（II）-α-diimine catalyst [(2,6-i-Pr)₂C₆H₃-DAB（An）]NiBr₂ plus MAO was immobilized on the surface of silica gel by physical adsorption，and the immobilized catalyst was used to catalyze polymerization of ethylene. The polymer properties were determined by GPC，DSC，IR，and were compared with the polymer made by homogeneous catalyst. The results showed that the Al/Ni molar ratio of immobilized Ni（II）-α-diimine catalyst was about 100. And the immobilized catalyst could catalyze the homopolymerization of ethylene in n-hexane. Compared with the polymer made by the homogeneous catalyst，molecular weight of the polymer and immobilized catalyst efficiency all decreased，while density，and T_m all increased. At a specific temperature，with the increase of Al/Ni molar ratio and ethylene pressure，branching degree of polyethylenes decreased，while molecular weight，density，T_m and immobilized catalyst efficiency all increased.

摘要：

将Ni（II）的二亚胺催化剂[(2,6-i-PrPh)₂DABAn]NiBr₂通过物理吸附法负载在硅胶上，并将负载化催化剂在正己烷作溶剂的条件下用于催化乙烯的配位聚合，通过GPC、DSC、IR等对聚合物性能进行了表征，并与均相催化剂催化烯烃聚合进行对比。结果表明：通过物理吸附法所得负载化催化剂Al/Ni摩尔比约为100。在正己烷作溶剂时，负载化Ni（II）的二亚胺催化剂能够催化乙烯的聚合。与均相催化剂聚合体系相比，负载化催化剂的催化效率降低，所得聚合物分子量降低，密度、熔点均增大。在一定温度下随 Al/Ni 摩尔比、乙烯压力的增大，负载化催化剂催化效率逐渐提高，聚乙烯的支化度减小，分子量、密度、熔点均增大。