MOLECULAR-WEIGHT DISTRIBUTION CONTROL WITH SUPPORTED METALLOCENE CATALYSTS

Several kinds of supported Cp(2)MeCl(2) (Me = Ti, Zr, Ht) catalysts were prepared with three different SiO2-supports; i.e., SiO2/MAO, SiO2/Al(C2H5)(3) and SiO2/(C2H5)MgCl. The SiO2-supported metallocene catalysts show fairly good activity for ethylene polymerization. The molecular weight distribution (MWD) of polyethylene obtained over SiO2-supported Cp(2)ZrCl(2) and Cp(2)HfCl(2) catalysts was narrow, and the shape of MWD was unimodal. In case of SiO2/MAO and SiO2/Al(C2H5)(3), supported Cp(2)TiCl(2) catalyst resulted in polyethylenes with bimodal MWD. In case of SiO2/C2H5MgCl, however, the supported Cp(2)TiCl(2) catalyst gave polyethylene with unimodal MWD.