Titanium(iv) complexes with OOO2−-type ligands as catalysts for the synthesis of ultra-high-molecular-weight polyethylene
摘要
A new fluorine-containing OOO2−-type chelating ligand and the titanium(iv) dichloride and bis-isopropoxide complexes with this ligand were synthesized. The structure of the titanium(iv) bis-isopropoxide complex was determined by single-crystal X-ray diffraction analysis. In the presence of Al/Mg activators (Et2AlCl-Bu2Mg or Et3Al2Cl3-Bu2Mg), both complexes catalyze the ethylene polymerization giving ultra-high-molecular-weight polyethylene with a molecular weight of up to 5.8 • 106 Da. Due to a low degree of polymer entanglement, these polymers can be processed by a solvent-free method to prepare high-strength high-modulus films with a Young’s modulus up to 117 GPa and a tensile strength up to 2.18 GPa.