Synthesis of Ultrahigh Molecular Weight Polyethylenes with New Catalyst Based on Ti4+ Complex with a Tridentate Phenoxyimine Ligand
摘要
Abstract
A novel catalyst system containing a complex of Ti4+ with a (O,N,O)-tridentate phenoxyimine ligand and a binary Al(C2H5)2Cl/Mg(C4H9)2 activator at a molar [Al]/[Mg] ratio of ~3 affords the synthesis of ethylene polymers with molecular weight in excess of 1 × 106. Ethylene homopolymer produced at 35°C has Mw ~ 2.6 × 106 and ethylene copolymers with small amounts (below 1 mol %) of 1-hexene, 1-octene and 1-decene have Mw ~ 1.5 × 106. The polymers have a relatively narrow molecular weight distribution (Mw/Mn ratio from 3.5 to 5), their mechanical properties are similar to properties of commercial UHMW polyethylenes.