The influence of heteroatom on catalytic properties of heterobimetallic Ti(IV)–Ca and Ti(IV)–Ba complexes in the production of UHMWPE

Abstract New heterobimetallic Ti(IV)–Ca and Ti(IV)–Ba complexes stabilized with fluorinated ligand – 2-[bis-CF3-hydroxymethyl]-4,6-tert-butylphenol have been synthesized; their compositions and structures have been confirmed by NMR, IR-spectroscopy and elemental analysis. The solid-state structures of complexes 1–2 were established by X-ray analysis. These complexes catalyze ethylene polymerization in the presence of a binary cocatalyst {3Et2AlCl + Bu2Mg}. In the result of this reaction Ultra High Molecular Weight Polyethylene (UHMWPE) with a broad molecular weight distribution is obtained. UHMWPE samples were processed into high-strength (up to 2.4 GPa) and high-modulus (over 130 GPa) oriented film tapes by a solid-state uniaxial deformation. Such parameters of UHMWPE samples indirectly indicate a low degree of entanglements between the macromolecular chains. The effect of the pre-catalysts composition on the catalytic activity and properties of the obtained polymer has been investigated.