Ethylene polymerization initiated by anchored CpIndZrCl(2) on silica with hexamethyltrisiloxane and pentamethylene spacers

For ethylene polymerization, the supported metallocene catalyst was prepare d by anchoring CpIndZrCl(2) on silica with an appropriate spacer. The three procedures were applied for CpIndZrCl(2), anchoring on silica with a hexam ethyltrisiloxane or pentamethylene spacer. The anchoring procedures exerted a strong influence on the catalyst activity since the different anchoring methods gave the formation of different structures of active sites. With th e new anchoring route, it was possible to prepare the "heterogeneous single -site" catalyst which was found to have only one catalyst structure on sili ca and exhibited a higher catalyst activity than that of the other supporte d catalysts. At a polymerization temperature of 70 degrees C, the activity of the heterogeneous single-site catalyst was comparable to that of the uns upported homogeneous zirconocene. (C) 1999 John Wiley & Sons, Inc.