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A kind of novel bridged nonmetallocene catalysts was synthesized by the
treatment of N,N-imidazole and N,N-phenylimidazole with n-BuLi, and MCl4 (M ¼
Ti, Zr) in THF. Those catalysts were performed for ethylene polymerization after activated
by methylaluminoxane (MAO). The effects of polymerization temperature, Al/M
ratio, pressure of monomer, and concentration of catalysts on ethylene polymerization
behaviors were investigated in detail. Those results revealed that the catalyst system
was favorable for ethylene polymerization with high catalytic activity. The polymer
was characterized by 13C NMR, WAXD, GPC, and DSC. The result confirmed that
the obtained polyethylene featured broad molecular weight distribution around 20,
linear structure, and relative low melting temperature. VVC 2007 Wiley Periodicals, Inc. J
Polym Sci Part A: Polym Chem 46: 33–37, 2008
Keywords: broad weight distribution; metallocene catalysts; methylaluminoxane;
nonmetallocene; polyethylene; structure