Synthesis of Ultrahigh-Molecular-Weight Polyethylene with [OSNO]-type Bis(phenolate) Titanium Complexes

The catalytic activity of seven titanium complexes with a [OSNO]-type bis(phenolate) ligand in ethylene polymerization has been studied at mild conditions of ethylene pressure (1.2 atm) and room temperature. It has been shown that in the presence of methylaluminoxane or triisobutyl aluminum modified methylaluminoxane cocatalyst, the activities of the titanium catalytic systems reach 86 kg PE/((mol catalyst) h) and lead to the preparation of ultrahigh-molecular-weight polyethylene. [OSNO]-type bis(phenolate) ligand structures have a great influence on the structure and molecular weight of polyethylene. The resulted polyethylenes are low long-chain branched polyethylene (n ≥ 6) or linear polyethylene and the melting temperatures of these polyethylenes are about 128–133°C.