Immobilized on MgCl2 bis(phenoxy-imine) complexes of Ti and Zr as catalysts for preparing UHMWPE and ethylene/higher α-olefin copolymers

Гагиева, С. Ч.; Тuskaev, Vladislav А.; Magomedov, Kasim F.; Москаленко, М. А.; Pavlov, Alexander A.; Meshchankina, Marina Yu.; Shcherbina, Maxim A.; Булычев, Б. М.

doi:10.1007/s00289-021-03885-6

Cited by 8 publications

(10 citation statements)

References 45 publications

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“…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. 17 Recently, Li et al reported a POSS-modified Ziegler−Natta catalyst system.…”

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%

“…reported a nanoparticle-supported catalytic system, Tuskaev et al . reported a novel Ziegler–Natta type catalytic system to synthesize solid-state processable materials, and different titanium complexes were immobilized on a MgCl 2 support. ,− , MgCl 2 immobilized bis(phenoxy-imine) complexes of Ti and Zr for the synthesis of UHMWPE have also been reported recently . Chikkali et al .…”

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%

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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“…The predominant cationic nature of the catalyst complex is compatible with anionic oligomeric species such as methylaluminoxane (MAO) or other surfaces activated with MAO. [12] Previously, magnesium chloride, [13] silica, [14] clays, [15] zeolites, [16] and layered double hydroxides (LDHs) [17][18][19] have been used as supports for metallocene catalysts. Materials applied for supporting metallocenes should contain Lewis acid sites, as in the case of silica and alumina, [20] or surface functional groups should exist that can be treated with MAO to form activated support.…”

Section: Introductionmentioning

confidence: 99%

Enhancing Metallocene Catalyst Activity: Utilizing Layered Double Hydroxide for Ethylene–Propylene Copolymerization

Mazhar,

Shehzad,

Hong

et al. 2023

Macro Materials & Eng

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This study reports the heterogenization of metallocene catalysts on sodium dodecyl sulfate (DDS)‐modified layered double hydroxides (LDHs) for efficient ethylene–propylene (EP) slurry‐phase copolymerization. The LDH support offers considerable compositional tunability. NiFe LDHs with different anions () and metallic compositions are applied as support for the metallocene catalysts; these significantly influence the catalytic properties of the heterogenized catalyst system. The supported‐catalyst intercalating DDS− anion in the galleries of NiFe and ZnAl LDHs demonstrates a high catalytic activity. They produce EP copolymers with high molecular weights (Mw) and wide polydispersity, compared with the homogeneous Zr catalyst. Further, the supported catalyst complex containing anion produces EP with a tenfold high Mw and demonstrate subdued catalytic activity. The higher basicity of the support is associated with the enhanced activity and the wider polydispersity of the EP pertaining to the different interactions of the catalyst molecule with the support. Overall, Ni‐containing LDH favors a higher activity, whereas Fe‐containing LDH favors a higher Mw. Therefore, NiFe‐based LDH results in both higher activity and molecular weight. 13C and 27Al magnetic angle spinning solid‐state nuclear magnetic resonance confirm the formation of the supported catalyst complex.

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“…In our early works, we demonstrated the possibility of using mixtures of alkylaluminium chlorides with dibutylmagnesium for the activation of phenoxy-imine pre-catalysts [ 21 , 22 ]. In such catalytic systems, MgCl 2 is formed in situ [ 23 , 24 ], however, in much smaller amounts.…”

Section: Introductionmentioning

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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Immobilized on MgCl2 bis(phenoxy-imine) complexes of Ti and Zr as catalysts for preparing UHMWPE and ethylene/higher α-olefin copolymers

Cited by 8 publications

References 45 publications

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Enhancing Metallocene Catalyst Activity: Utilizing Layered Double Hydroxide for Ethylene–Propylene Copolymerization

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

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