Growth of Polyethylene Nanofibrils Over rac-Et(Indenyl)_2ZrCl_2/MAO Catalyst Supported on Silica Nanotubes

摘要

The morphology of polyethylene synthesized over rac-Et(indenyl)2ZrCl2/MAO catalyst supported on silica nanotubes of anodized aluminum oxide (AAO) template and on liberated silica nanotubes have been studied. A silica nanotube is quickly filled up with polymer, which extrudes out to the bulk liquid phase as nanofibrils of 30–35nm diameter with high crystallinity. When silica nanotubes are liberated from the AAO template and deposited with catalysts, the polyethylene nanofibrils formed at the outer surface of the silica nanotubes also grow as 30–35nm diameter fibrils and they quickly entangle to a mass of polymers in the liquid phase. The liberated silica nanotube reactors showed much higher ethylene polymerization activity than the micro silica particle-supported catalyst.