出 处:《Chinese Journal of Polymer Science》2014年第7期854-863,共10页高分子科学(英文版)
基 金:financially supported by the National Natural Science Foundation of China(Nos.20936006 and 20976152);National Basic Research Program of China(2011CB606001);Doctoral Program of Higher Education of China(No.20100101110041);Program for Changjiang Scholars and Innovative Research Team in Zhejiang University
摘 要:This contribution reports ethylene polymerization behavior of titanium complexes incorporating bis(phenoxyimine) ligands. Six phenoxy-imine Ti(IV) complexes {6-R^1-2-[CH=N(2,6-difluoro-3,5-diR^2-4-R^3Ph)]C6H30}2TiCl2 (1: R^1 = H, R^2 = H, R^3 = H; 2: R^1 = H, R^2 = H, R%3 = 4-vinylphenyl; 3: R^1 = CH3, R^2 = H, R^3 = H; 4: R^1 = CH3, R^2 = H, R^3 = 4-vinylphenyl; 5: R^1 = CH3, R^2 = F, R^3 = H; 6: R^1 = CH3, R^2 = F, R^3 = 4-vinylphenyl) have been synthesized and evaluated for ethylene polymerization using dried MAO (simplified as DMAO) as cocatalyst. An obvious catalytic heterogeneity of Cat 2 (Complex 2/DMAO) towards ethylene polymerization was observed, which was illustrated by decreased activity, multi- modal molecular weight distribution and partially improved particle morphology comparing with Cat 1. Moreover, Cat 3 exhibits "living" characteristics in the process under certain conditions (25 ~C, less than 20 min). Otherwise, the moderate to high ethylene polymerization activity of ca. 105-106 g PE/(mol Ti'h) and high molecular weight (Mw = 105-106) of polyethylene can be obtained by changing the skeleton structure of these complexes.This contribution reports ethylene polymerization behavior of titanium complexes incorporating bis(phenoxyimine) ligands. Six phenoxy-imine Ti(IV) complexes {6-R^1-2-[CH=N(2,6-difluoro-3,5-diR^2-4-R^3Ph)]C6H30}2TiCl2 (1: R^1 = H, R^2 = H, R^3 = H; 2: R^1 = H, R^2 = H, R%3 = 4-vinylphenyl; 3: R^1 = CH3, R^2 = H, R^3 = H; 4: R^1 = CH3, R^2 = H, R^3 = 4-vinylphenyl; 5: R^1 = CH3, R^2 = F, R^3 = H; 6: R^1 = CH3, R^2 = F, R^3 = 4-vinylphenyl) have been synthesized and evaluated for ethylene polymerization using dried MAO (simplified as DMAO) as cocatalyst. An obvious catalytic heterogeneity of Cat 2 (Complex 2/DMAO) towards ethylene polymerization was observed, which was illustrated by decreased activity, multi- modal molecular weight distribution and partially improved particle morphology comparing with Cat 1. Moreover, Cat 3 exhibits "living" characteristics in the process under certain conditions (25 ~C, less than 20 min). Otherwise, the moderate to high ethylene polymerization activity of ca. 105-106 g PE/(mol Ti'h) and high molecular weight (Mw = 105-106) of polyethylene can be obtained by changing the skeleton structure of these complexes.
关 键 词:Ethylene polymerization Catalytic heterogeneity "Living" polymerization Phenoxy-imine ligand 4-Vinylphenyl group.
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