Copolymerization of Ethylene andα-Olefin Using Et(Ind)2ZrCl2 Entrapped inside the Regular and Small Pores of MCM-41

Copolymerizations of ethylene with propylene, and ethylene with 1-octadecene were performed with MCM-41/MAO/Et(Ind)2ZrCl2 and the resulting copolymers were analyzed by NMR, GPC, and DSC. A comonomer enhancement effect was observed in the case of ethylene-propylene copolymerization with both supported and unsupported catalysts. However, it was not observed in the case of ethylene-1-octadecene copolymerization with MCM-41/MAO/Et(Ind)2ZrCl2, while unsupported Et(Ind)2ZrCl2 showed the comonomer enhancement effect under the same polymerization conditions. Propylene content in the copolymer of MCM-41/MAO/Et(Ind)2ZrCl2 was higher than that of unsupported Et(Ind)2ZrCl2 , suggesting the presence of more stereoregulating active sites and lower concentration of MAO around active sites inside the pores of MCM-41.