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作 者:Yu-Yin Wang Chao-Qun Wang Xiao-Qiang Hu Yan Xia Yue Chi Yi-Xin Zhang Zhong-Bao Jian
机构地区:[1]College of Chemistry and Life Science,Advanced Institute of Materials Science,Changchun University ofTechnology,Changchun 130012,China [2]Key Laboratory of Advanced Structural Materials of Ministry of Education,College of Material Science and Engineering,Changchun University of Technology,Changchun 130012,China [3]State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China
出 处:《Chinese Journal of Polymer Science》2021年第8期984-993,I0006,共11页高分子科学(英文版)
基 金:the National Natural Science Foundation of China(Nos.21871250 and 22001244);the Jilin Provincial Science and Technology Department Program(No.20200801009GH).
摘 要:For the rational design of metal catalyst in olefin polymerization catalysis,various strategies were applied to suppress the chain transfer by bulking up the axial positions of the metal center,among which the"sandwich"type turned out to be an eficient category in achieving high molecular weight polyolefin.In the a-dimine system,the"sandwich"type catalysts were built using the typical 8-aryl-naphthyI framework.In this contribution,by introducing the rotationally restrained benzosuberyl substituent into the ortho-position of N-aryl rings,a new class of "sandwich-like"a-diimine nickel catalysts was constructed and fully identified.The rotationally restrained benzosuberyl substituents played a"sandwich-like"function by capping the nickel center from two axial sites.Compared to the nickel catalyst Ni1 bearing freely rotated benzhydryl substituent,Ni2 featuring benzosubery|substituent enabled the increase(8 times)of polymer molecular weights from 8 kDa to 65 kDa in the polymerization of ethylene.By further increasing the steric bulk of another ortho-site of the N-aryl ring,the polymer molecular weight even reached an ultrahigh level of 833 kDa(Mw=1857 kDa)using the optimized Ni3.Notably,these nickel catalysts could also mediate the copolymerization of ethylene with methyl 10-undecenoate,with Ni3 giving the highest copolymer molecular weight(88 kDa)and the highest incorporation of comonmer(2.0 mol1%),along with high activity of up to 10^(5)g·mol^(-1)·h^(-1).
关 键 词:Olefin polymerization Benzosuberyl substituent SANDWICH Nickel catalyst Polar monomer
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