Copolymerization of ethylene with 1-hexene or 1-hexadecene over siloxy-substituted metallocene catalysts

A series of ethylene copolymerizations with 1-hexene or 1-hexadecene over four different siloxy-substituted ansa-metallocene/methylaluminoxane (MAO) catalyst systems was studied. High copolymerization activities and comonomer responses were observed in all cases and high molecular weight ethylene copolymers were obtained. Unsaturations resulting from vinyl and vinylidene double bonds were observed in the produced copolymers. It can be concluded that the position of the siloxy substituent has a large influence on polymerization activity and that the replacement of the tert-butyldimethylsiloxy groups with tri-isopropylsiloxy groups increases copolymerization ability of the catalysts.