New titanium(IV) coordination compounds with 2-hydroxybenzyl alcohol derivatives used in the preparation of ultra-high molecular weight polyethylene

Abstract

A reaction of 2,4-bis(α,α-dimethylbenzyl)phenol with TiCl₂(ОPrⁱ)2 and Ti(ОPrⁱ)₄ was used to obtain the coordination compounds (HL)₂L₂Ti₂Cl₂•MeC₆H₅ and L₄Ti₄(OPrⁱ)₈, respectively. The compounds were characterized by elemental analysis, NMR spectroscopy, and X-ray diffraction. The titanium(IV) coordination compounds obtained polymerize ethylene in the presence of binary cocatalysts {3Et₂AlCl + Bu₂Mg} or {3Et₃Al₂Cl₃ + Bu₂Mg} at moderate to high rates, giving rise to ultra-high molecular weight polyethylene with a wide range of molecular masses. The highest values of tensile strength (2.4 GPa) and modulus of elasticity (ε = 2.67%) were obtained for the sample with a molecular mass of 3.14•10⁶ Da under comparable conditions of orientation drawing of the film filaments. This sample was obtained when complex (HL)2L₂Ti₂Cl₂ was activated by a 3: 1 mixture of Et₂AlCl—Bu₂Mg.