Linear/branched Block Polyethylene Produced by a-Diimine Nickel(Ⅱ)Catalyst and Bis(phenoxy-imine)Zirconium Binary Catalyst System in the Presence of Diethyl Zinc  

作　　者：Ding-Ding Zhao Yan-Hui Hou Ke-Ning Zong Mi-Mi Cui Bin-Yuan Liu Min Yang 

机构地区：[1]Hebei Key Laboratory of Functional Polymers,Institute of Polymer Science and Engineering,Hebei University of Technology,Tianjin 300130,China [2]State Key Laboratory of Separation Membranes and Membrane Processes,School of Material Science and Engineering,Tiangong University,Tianjin 300160,China

出　　处：《Chinese Journal of Polymer Science》2021年第12期1581-1589,共9页高分子科学（英文版）

基　　金：by the National Natural Science Foundation of China(Nos.21004017 and 21004043);the Natural Science Foundation of Hebei Provinee(No.B2015202049).

摘　　要：In order to promote development of linear/branched block polyethylenes based on new catalytic systems,we synthesized a novel a.dimine nickel(Ⅱ)complex with isopropyl substituents on ortho-N-aryl and hydroxymethyl phenyl substituents on para-Naryl structures.The activity of a-dimine nickl(Ⅱ)catalyst was 3.02x10^(6)g-mol_(ni)^(-1)·h^(-1) at 70℃,and resultant polyethylene possessed 135/1000C branches.The linear/branched block polyethylenes were synthesized from ethylene polymerization catalyzed by the a-dimine nicke(Ⅱ)complex/bis(phenoxy-imine)zirconium in the presence of diethyI zinc.With the addition of ZnEtz(from 0 to 400),the melting peak of resultant polyethylene changed from a single melting peak to bimodal melting peaks.The molecular weights of resultant polyethylene ranging from 26.8 kg/mol to 17.1 kg/mol and PDI values varying gradually from 24.4 to 15.2 were obtained vla adjusting ZnEt;equiv.and molar ratio of two catalysts.In addition,the branching degree of the polyethylene increased from 13/1000C to 56/1000 with the increase of the proportion of a dimine nickel(Ⅱ)catalyst.Using this binary catalyst system,the reaction temperature of chain shutting polymerization can be carried out at 70℃,which is more conducive to industrial application.

关 键 词：Chain shuttling polymerization Linear/branched block polyethylene a-Diimine nickel Bis(phenoxy-imine)zirconium Ethylene 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业] TQ426