Study on the polymerization of ethylene with carbon bridged dinuclear metallocene of Ti-Sm and Zr-Sm

It has been synthesized two new dinuclear metallocene complexes ,which were used for ethylene polymerization with MAO as cocatalyst. Detailed study on the effect of polymerization caused by catalyst concentration, molar ratio of /, temperature and time, showed that the catalytic activity of complex 7 is higher than that of the corresponding mononuclear metallocene of Cp_2TiCl_2, while the catalytic activity of complex 5 is lower than that of the corresponding mononuclear metallocene of Cp_2ZrCl_2; The molecular weight (M_η) of polyethylene produced by above two catalyst systems is somewhat decreased, and the molecular weight distribution (MWD) becomes broader. With prolongation of time, the molecular weight of polyethylene obtained by complex 7 decreases, while the molecular weight of polyethylene obtained by complex 5 increases.