High-Performance Catalysts Based on Hybrid Salicylaldarylimine Complexes of Titanium(IV) Dichloride for the Synthesis of Ultrahigh Molecular Weight Polyethylene with Unentangled Macromolecules

Abstract

The features of ethylene polymerization in the presence of dichloridobis(salicylaldaryliminato)titanium(IV) complexes containing a 4-allyloxy-2,3,5,6-tetrafluorophenylimino group, namely, {2‑[(4-CH₂=CH-CH₂O)C₆F₄N=CH]-6-R¹-4-R²-C₆H₂O}₂TiCl₂ (R¹ = t-Bu, CMe₂(Ph); R² = H, Me, OMe, t-Bu, CMe₂(Ph), Cl, Br) in the presence of methylalumoxane, have been studied. All the complexes exhibit high catalytic activity (up to 27.8 × 10⁶ g_PE \({\text{mol}}_{{{\text{Ti}}}}^{{ - 1}}\) \({\text{MPa}}_{{{{{\text{C}}}_{2}}{{{\text{H}}}_{4}}}}^{{ - 1}}\) h^–1) in the temperature range of 10‒60°C and form powdered ultrahigh molecular weight polyethylene (UHMWPE) (M = (4.4–16.0) × 10⁶ g/mol) with a low number of intermolecular entanglements. It has been shown that during polymerization, the complexes are immobilized on UHMWPE macromolecules.