Binuclear and Hexanuclear Ti(IV) Complexes Supported by [OOOO]4–-type Ligand for Preparing Disentangled UHMWPE

Тuskaev, Vladislav А.; Гагиева, С. Ч.; Kurmaev, Dmitrii A.; Васильев, В. Г.; Kolosov, Nikolay A.; Zubkevich, Sergey V.; Mikhaylik, Elena S.; Golubev, Evgenii K.; Никифорова, Г. Г.; Zhizhko, Pavel A.; Серенко, О. А.; Булычев, Б. М.

doi:10.1007/s10118-019-2197-0

Cited by 15 publications

(9 citation statements)

References 29 publications

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“…Rastogi et al reported a nanoparticle-supported catalytic system, 10 Tuskaev et al reported a novel Ziegler−Natta type catalytic system to synthesize solid-state processable materials, 26 and different titanium complexes were immobilized on a MgCl 2 support. 20,[22][23][24][25]27 MgCl 2 immobilized bis(phenoxyimine) complexes of Ti and Zr for the synthesis of UHMWPE have also been reported recently. 21 Chikkali et al disclosed a modified Ziegler−Natta catalyst system with MMAO-12 as cocatalyst to access the disentangled UHMWPE.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The resulting polymer should be suitable for uniaxial and biaxial solid-state processing and is expected to match the mechanical properties of the homogeneous catalysis counterpart. Although the synthesis of UHMWPE using a heterogeneous catalytic system is not new, ,− the low entangled state that can lead to properties equivalent to those of the homogeneous catalytic system has not been reported yet. Below, experimental findings for the synthesis of UHMWPE using heterogeneous catalytic systems are recalled.…”

Section: Introductionmentioning

confidence: 99%

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Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

et al. 2022

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Several homogeneous postmetallocene complexes are known to produce weakly entangled ultrahigh-molecular-weight polyethylene (disentangled UHMWPE) under controlled polymerization conditions leading to ultimate mechanical properties. Major challenges in using a homogeneous catalyst system exist such as reactor fouling and uncontrolled polymer morphology, which could be addressed by heterogenization of the single-site complex. In such a scenario, a heterogeneous catalytic system that can synthesize ultrahigh-molecular-weight polyethylene with a reduced number of entanglements, to an extent that the mechanical properties are equivalent to those obtained using a postmetallocene catalyst in a homogeneous condition, remains a challenge. Herein, a magnesium chloride based in situ formed activator/support, MgCl x /Et n Al y (2-ethyl-1-hexoxide) z , is employed with a highly active bis[N-(3-tert-butylsalicylidene)pentafluoroanilinato] titanium(IV) dichloride (Cat. 1) for the synthesis of ultrahigh-molecular-weight polyethylene with a reduced number of entanglements. A novel route is adopted to make a nano-support that allows tailoring of the entangled state and control over the resultant morphology without reactor fouling and wall sheeting, thus providing the feasibility of pursuing the polymerization via a continuous process. The synthesized nascent polymer shows the formation of single crystals of linear UHMWPE, identifying the fold surface and crystal thickness and suggesting a low entangled state. The topological differences with the commercial entangled sample are identified by chain diffusion from the noncrystalline to crystalline region via solid-state NMR, following melting kinetics via DSC, and transformation of the nonequilibrium melt into the equilibrium state via rheology. Thus, the obtained disentangled crystals can be compressed in the solid state, without melting, to an extent that the macroscopic forces can be transferred to the molecular level. This allows the desired chain orientation for securing the ultimate tensile modulus (>200 N/tex) and tensile strength (>4.0 N/tex) in the synthesized low entangled linear polyethylene having a weight average molar mass exceeding a million grams per mole. These mechanical properties are equivalent to those perceived using a homogeneous catalytic system and are the first of their kind reported in a polymer synthesized using a heterogeneous catalytic system.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

et al. 2022

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“…The authors [ 7 ], using the melt rheological method, showed that UHMWPE obtained on such systems is not monomodal (the classical method for determining MWD-GPC is unacceptable for UHMWPE). However, the use of Al/Mg activators leads to the formation of a set of inhomogeneous catalytically active sites, and, as a consequence, to an even more significant MWD broadening [ 46 , 47 , 48 ].…”

Section: Resultsmentioning

confidence: 99%

Effect of Activator and Outgoing Ligand Nature on the Catalytic Behavior of Bis(phenoxy-imine) Ti(IV) Complexes in the Polymerization of Ethylene and Its Copolymerization with Higher Olefins

et al. 2022

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A series of bis(phenoxy-imine) (FI) titanium(IV) and zirconium(IV) complexes have been synthesized. The effect of the nature of the activator (MAO, combinations EtnAlCl3-n + Bu2Mg and iBu3Al + [Ph3C]+[B(C6F5)4]−) on the catalytic activity and properties of the resulting polymers was studied. It was found that Ti-Fi complexes, despite the nature of the outgoing ligands (Cl or iPrO) in the presence of Al/Mg activators, effectively catalyze the polymerization of ethylene (with the formation of UHMWPE); copolymerization of ethylene with 1-octene (with the formation of ultra-high molecular weight copolymers); and the ternary copolymerization of ethylene, propylene and 5-vinyl-2-norbornene (with the formation of polyolefin elastomers). It has been shown that Zr-FI complexes are not activated by these Al/Mg compositions. The resulting UHMWPE can be processed by a solventless method into high-strength and high-modulus oriented films; however, their mechanical characteristics do not exceed those obtained using MAO.

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“…[3][4][5][6][7] It was previously shown that binuclear and hexanuclear titanium complexes stabilized by a tetradentate derivative of 2-hydroxymethylphenol showed significantly higher catalytic activity and thermal stability in ethylene polymerization in comparison to mononuclear analogue. [8,9] One of the most important factors in the design of binuclear and polynuclear olefin polymerization precatalysts is the distance between the metal centers. In this sense, it is interesting to explore the possibilities of compartmental ligands proposed by Robson in 1970 as "a ligand capable of securing two metal ions in close proximity."…”

Section: Introductionmentioning

confidence: 99%

“…It was previously shown that binuclear and hexanuclear titanium complexes stabilized by a tetradentate derivative of 2‐hydroxymethylphenol showed significantly higher catalytic activity and thermal stability in ethylene polymerization in comparison to mononuclear analogue. [ 8,9 ]…”

Section: Introductionmentioning

confidence: 99%

Binuclear Ti(IV) complex with new compartmental ligand 2,6‐(bis‐CF₃‐carbinol)‐4‐tert‐butylphenol as precatalysts for ethylene polymerization and its copolymerization with propylene and 5‐ethylidene‐norbornene

Тuskaev

Гагиева

Bogdanov

et al. 2021

Applied Organom Chemis

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The coordination chemistry of a new compartmental ligand 2,6‐(bis‐CF3‐carbinol)‐4‐tert‐butylphenol with Ti(IV) and Zr(IV) has been studied. The structures of Al, Ti, and Zr complexes with the participation of this ligand were established by X‐ray diffraction. Upon activation with Et2AlCl or Et3Al2Cl3 and Bu2Mg, Ti(IV) complex exhibited moderate catalytic activity for ethylene polymerization. The obtained UHMWPE samples were processed into high‐strength (up to 2.7 GPa) and high‐modulus (up to 162 GPa) films through solid‐phase molding and orientation drawing. The mononuclear and binuclear Ti(IV) complexes catalyzed the ternary copolymerization of ethylene, propylene, and 5‐ethylidene‐norbornene. Tercopolymers with a content of propylene units up to 36 mol% and 5‐EBN up to 8.6 mol% were synthesized with a high activity (2.8–6.3 tons of copolymer/mol Ti h); the mechanical characteristics of elastomeric materials have been studied.

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Binuclear and Hexanuclear Ti(IV) Complexes Supported by [OOOO]4–-type Ligand for Preparing Disentangled UHMWPE

Cited by 15 publications

References 29 publications

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Effect of Activator and Outgoing Ligand Nature on the Catalytic Behavior of Bis(phenoxy-imine) Ti(IV) Complexes in the Polymerization of Ethylene and Its Copolymerization with Higher Olefins

Binuclear Ti(IV) complex with new compartmental ligand 2,6‐(bis‐CF₃‐carbinol)‐4‐tert‐butylphenol as precatalysts for ethylene polymerization and its copolymerization with propylene and 5‐ethylidene‐norbornene

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Binuclear and Hexanuclear Ti(IV) Complexes Supported by [OOOO]4–-type Ligand for Preparing Disentangled UHMWPE

Cited by 15 publications

References 29 publications

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Effect of Activator and Outgoing Ligand Nature on the Catalytic Behavior of Bis(phenoxy-imine) Ti(IV) Complexes in the Polymerization of Ethylene and Its Copolymerization with Higher Olefins

Binuclear Ti(IV) complex with new compartmental ligand 2,6‐(bis‐CF3‐carbinol)‐4‐tert‐butylphenol as precatalysts for ethylene polymerization and its copolymerization with propylene and 5‐ethylidene‐norbornene

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Binuclear Ti(IV) complex with new compartmental ligand 2,6‐(bis‐CF₃‐carbinol)‐4‐tert‐butylphenol as precatalysts for ethylene polymerization and its copolymerization with propylene and 5‐ethylidene‐norbornene