First example of cationic titanium (III) complexes with crown ether as catalysts for ethylene polymerization

Complex cations with a vacant coordination site are considered as the most plausible catalytically active centers of metallocene and post-metallocene polymerization catalysts. For the first time we demonstrated that cationic titanium (III) complexes stabilized with crown ether can be used as pre-catalysts for ethylene polymerization. In the presence of alkyl aluminum chlorides and MgBu2 as cocatalysts, these complexes catalyze ethylene polymerization to produce Ultra High Molecular Weight Polyethylene (UHMWPE) with productivity up to 4650 kgPE/mol Ti h⋅atm and molecular weight up to 1.8·106 Da. UHMWPE powders were processed by the solid-phase method with subsequent orientation drawing into high-strength (1.4–2.1 GPa) and high-modulus (91–118 GPa) films. © 2022 Elsevier Lt

Novel alkoxo-titanium(IV) complexes with fluorinated 2-hydroxymethylphenol derivatives as catalysts for the formation of ultra-high molecular weight polyethylene nascent reactor powders

A series of titanium (IV) complexes 3a–g stabilized by fluorinated derivatives of 2-hydroxymethylphenol have been synthesized; their composition and structure have been confirmed by NMR, IR-spectroscopy and elemental analysis. The structures of compounds 3c, 3f and 3g have been unambiguously established by X-ray diffraction study. The complexes in the presence of a binary cocatalysts {alkyl aluminum chloride + MgBu2} catalyze ethylene polymerization to afford Ultra High Molecular Weight Polyethylene (UHMWPE). The effects of substituents in the ligands on the catalytic activity and properties of the obtained polymer – molecular weight, DSC melting behavior, and morphology of nascent reactor powders have been investigated. UHMWPE samples were processed by a solid-state uniaxial deformation into high-strength (up to 2.65 GPa) and high-modulus (over 140 GPa) oriented film tapes, which indirectly indicates a low degree of entanglements between the macromolecular chains. © 2019 Elsevier B.V