Ethylene Polymerization Initiated by Anchored CpIndZrCl_2 on Silica with Hexamethyltrisiloxane and Pentamethylene Spacers

摘要

For ethylene polymerization, the supported metallocene catalyst was prepared by anchoring CpIndZrCl_2 on silica with an appropriate spacer. The three procedures were applied for CpIndZrCl_2 anchoring on silica with a examethyltrisiloxane 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 the new anchoring route, it was possible to prepare the “heterogeneous single-site”catalyst which was found to have only one catalyst structure on silica and exhibited a higher catalyst activity than that of hte other supported catalysts. At a polymerization temperature of 70deg C, the activity of the heterogeneous single-site catalyst was comparable to that of the unsupported homogeneous zirconcene.