A Titanium(IV) Complex with an OSO-Type Ligand as a Catalyst for the Synthesis of Ultrahigh-Molecular-Weight Polyethylene

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

“…The UHMWPE nascent reactor powders 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. Comparing the results obtained with previously published data on the Ti diolate complexes (containing no perfluorinated fragments), [ 19–21,24 ] it can be noted that the introduction of an additional donor atom does not increase the catalytic activity but significantly improved the mechanical characteristics of oriented films. The mechanical characteristics of the obtained oriented UHMWPE films do not surpass to the best published data (e.g., disentangled UHMWPE obtained on the bis[(3‐ tert ‐butylsalicylidene)pentafluoroanilinato]titanium(IV) dichloride activated with 1000 eq.…”

“…The fruitfulness of such an approach was shown in Tuskaev et al [ 24 ] and describing the synthesis of the UHMWPE powders suitable for solid‐phase processing on titanium complexes with diolate ligands containing an additional donor sulfur atom (compound VII , Figure 1). In this work, we obtained precatalysts of the desired LTi(OAlk) 2 composition using tridentate diolate ligand with an additional neutral donor oxygen atom, the structure of which suggests the formation of two stable five‐membered chelate rings.…”

New Titanium(IV)-Alkoxide Complexes Bearing Bidentate OO Ligand with the Camphyl Linker as Catalysts for High-Temperature Ethylene Polymerization and Ethylene/1-Octene Copolymerization

“…The nature of the organoaluminum compound (OAC) included in the Al/Mg activator did not significantly affect these parameters. The results obtained slightly exceeded those previously published for titanium complexes with diol ligands [ 17 , 18 , 21 , 25 , 26 , 27 ]; however, the reason may be not only the structure of the precatalysts, but also the polymerization temperature (in the cited works, polymerization was carried out at 30 °C). For comparison, the modulus value for commercially available gel-spun UHMWPE fiber, produced by the gel-spinning process, is 113 GPa [ 38 ].…”

“…Previously, we reported on the ability of various titanium(IV)–diolate complexes VII-X [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], including those with additional heteroatoms [ 23 , 24 , 25 , 26 , 27 ] ( Chart 1 ), to catalyze the (co)polymerization of ethylene in the presence of such Al/Mg activators. This group of postmetallocene precatalysts is poorly studied, which is most likely due to the specifics of their activation: in the presence of trialkylaluminum derivatives, alkylaluminum chlorides, or alkylalumoxanes (traditional activators in Ziegler–Natta catalysis), and the activity of these systems is low or does not manifest itself at all.…”

“…An essential point limiting the possibility of the industrial implementation of this group of catalysts is their low thermal stability. As a rule, the maximum productivity of such systems is achieved at a temperature of 30 °C [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]; an increase in the polymerization temperature to 50–80 °C is accompanied by deactivation and a significant reduction in the polymer’s molecular weight. The aim of this work is the structural modification of the ligand environment of the metal, aimed at increasing the thermal stability of the considered precatalysts.…”