Novel titanium(IV) diolate complexes with additional O‐donor as precatalyst for the synthesis of ultrahigh molecular weight polyethylene with reduced entanglement density: Influence of polymerization conditions and its implications on mechanical properties

• Published in: Applied organometallic chemistry Vol. 35; no. 7
• Main Authors: Tuskaev, Vladislav A., Gagieva, Svetlana Ch, Kurmaev, Dmitrii A., Bogdanov, Vyacheslav S., Magomedov, Kasim F., Mikhaylik, Elena S., Golubev, Evgenii K., Buzin, Mikhail I., Nikiforova, Galina G., Vasil'ev, Viktor G., Khrustalev, Viktor N., Dorovatovskii, Pavel V., Bakirov, Artem V., Shcherbina, Maksim А., Dzhevakov, Pavel B., Bulychev, Boris M.
• Format: Journal Article
• Language: English
• Published: Chichester Wiley Subscription Services, Inc 01-07-2021
• Subjects: catalysts; Chemical synthesis; Chemistry; Coordination compounds; Entanglement; Ligands; Mechanical properties; Modulus of elasticity; Molecular weight; Molecular weight distribution; Oxygen atoms; Polyethylene; Polymerization; Polymers; Titanium; titanium(IV) complexes; Ultra high molecular weight polyethylene; ultrahigh molecular weight polyethylene; Weight reduction; Ziegler–Natta polymerization
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.6256

New alkoxo‐titanium(IV) complexes with diolate ligand containing additional donor oxygen atom have been synthesized from readily available and scalable precursors. The structure of complex 4 was established by X‐ray diffraction. Titanium atom adopts a distorted tetrahedral geometry formed by six oxygen atoms of ligands. The resulting complexes 3–4 are moderately or highly active in ethylene polymerization in the presence of {EtnAlCl3–n + Bu2Mg} binary cocatalysts. The influence of the nature of the solvent, the organoaluminum cocatalyst and the polymerization temperature on the activity of catalytic systems, and the properties of the resulting polymers were studied. The obtained polymers are linear polyethylene of ultrahigh molecular weight (up to 5.8·106 g mol−1) with a broad molecular weight distribution. The polymers are suitable for the modern methods of polymer processing—the solventless solid‐state formation of super high‐strength (breaking strength up to 2.8 GPa) and high‐modulus (elastic modulus up to 140 GPa) oriented films and film tapes. The possibility of scaling up the synthesis of ultrahigh molecular weight polyethylene (UHMWPE) without a significant drop in the productivity of the catalytic system and polymer properties is shown. UHMWPE samples have been investigated by small‐angle X‐ray scattering (SAXS) methods to study the structural changes induced by solid‐state drawing of nascent reactor powders.
New Ti(IV) complexes with OOO2−‐type diolate ligand have been synthesized. Complexes activated by {EtnAlCl3–n + Bu2Mg} catalyzed synthesis of disentangled ultrahigh molecular weight polyethylene (UHMWPE) (Mv up to 5.8·106 Da). Polymer samples were processed by a solvent‐free method into high‐strength (up to 2.8 GPa) and high‐modulus (up to 140 GPa) oriented film tapes.