Ethylene Polymerization by Thioether Bridged Dinuclear Zirconocene Complex
The thioether bridged Zirconocene complex [(C5H5)Cl2ZrC5H4CH2CH2]2S has been synthesized by treating the dilithium salts of the thioether bridged cyclopentadienyl ligand with two equivalents of C5H5ZrCl3(DME) and characterized by 1HMNR and elemental analysis. Homogenous ethylene polymerization by this complex has been conducted systematically in the presence of methylaluminoxane (MAO). The influence of the molar ratio [MAO]/[Cat], the catalyst concentration, time and temperature have been studied in detail. The catalytic activity of 1 is 6.46×105 g PE/mol•Cat•h. Higher temperature is favorable for increasing the catalytic activity for 1. A high concentration of the catalysts drops the catalytic activity as well as the molecular weight of polyethylene for the complex. High temperature gel permeation chromatography (HT-GPC) proves the production of polyethylene with a broad molecular weight distribution (MWD).
Y. J. Nie and M. Yang, "Ethylene Polymerization by Thioether Bridged Dinuclear Zirconocene Complex", Advanced Materials Research, Vol. 213, pp. 374-377, 2011