Synthesis of Ultrahigh Molecular Weight Polyethylenes with New Catalyst Based on Ti4+ Complex with a Tridentate Phenoxyimine Ligand

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 M_w ~ 2.6 × 10⁶ and ethylene copolymers with small amounts (below 1 mol %) of 1-hexene, 1-octene and 1-decene have M_w ~ 1.5 × 10⁶. The polymers have a relatively narrow molecular weight distribution (M_w/M_n ratio from 3.5 to 5), their mechanical properties are similar to properties of commercial UHMW polyethylenes.