Chem. J. Chinese Universities ›› 1998, Vol. 19 ›› Issue (7): 1178.

• Articles • Previous Articles     Next Articles

A Kinetic Study on Ethylene Polymerization by Cp2ZrCl2/iso-Butylalumoxane

FAN Zhi-Qiang, WENG Jian-Hua, WANG Qi, FENG Lin-Xian   

  1. Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027
  • Received:1997-03-12 Online:1998-07-24 Published:1998-07-24

Abstract: iso-Butylalumoxane(BAO) has been synthesized and characterized, and ethylene polymerization catalyzed by Cp2ZrCl2/BAO has been investigated. The polymerization rate curves at different catalyst concentrations, Al/Zr molar ratio and polymerization temperature are determined and compared to the kinetic behavior of ethylene polymerization catalyzed by Cp2ZrCl2/methylalumoxane(MAO) reported in literature. On the basis a tentative model for the cocatalytic action of BAO has been proposed: only a kind of multi molecular aggregates of BAO can act as cocatalyst of metallocenes. Because of the low stability of the BAO aggregates, Cp2ZrCl2/BAO system shows a moderate catalytic activity only at relatively high BAO concentration and medium temperature. The main reason for the lower activity of BAO than MAO is the absence of highly active species which is stable at low concentration and high temperature.

Key words: Metallocene, iso Butylalumoxane, Ethylene, Polymerization

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