Effects of residual and external alkylaluminum on the synthesis of syndiotactic polystyrene with cyclopentadienyltitanium tribenzyloxide-methylaluminoxane catalyst

Wu, Qing; Gao, Qinghai; Lin, Shangan

doi:10.1002/(sici)1097-4628(19981024)70:4<765::aid-app16>3.0.co;2-w

Cited by 9 publications

(1 citation statement)

References 13 publications

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“…Nevertheless, too high Al/Ni mole ratios decreased the molecular weight and conversion (Entry 5, 6). This can be ascribed to the chain transfer or termination with AlMe 3 , which is usually contained in MAO 16…”

Section: Resultsmentioning

confidence: 99%

Polymerization of β‐pinene with Schiff‐base nickel complexes catalyst: Synthesis of relatively high molecular weight poly(β‐pinene) at high temperature with high productivity

Liang

et al. 2007

J. Polym. Sci. A Polym. Chem.

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A series of easily accessible and stable Schiff‐base nickel complexes (complex 1–4) in conjunction with methylaluminoxane (MAO) were employed for the synthesis of relatively high molecular weight β‐pinene polymers at high temperature with high productivity. The ligand structure of the complex had a substantial effect on the polymerization in terms of the productivity and the molecular weight. With complex 4 in the presence of MAO, high molecular weight polymers of β‐pinene (Mn ∼ 10,900) were obtained at 40 °C with an extremely high productivity up to 1.25 × 107 g polyβ‐pinene/mol of Ni. 1H NMR analyses showed that the obtained β‐pinene polymer was structurally identical to that formed by conventional cationic Lewis acid initiators. The polymerization was presumably initiated by the nickel cation formed by the reaction of the schiff‐base nickel complex and MAO, while the propagation proceeded in a manner typical for a conventional carbocationic polymerization process. Direct evidence for the carbocationic polymerization was offered by the fact that quenching of the polymerization with methanol at a low monomer conversion resulted in incorporation of a methoxyl end group into the polymer chain. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3739–3746, 2007

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Section: Resultsmentioning

confidence: 99%

Polymerization of β‐pinene with Schiff‐base nickel complexes catalyst: Synthesis of relatively high molecular weight poly(β‐pinene) at high temperature with high productivity

Liang

et al. 2007

J. Polym. Sci. A Polym. Chem.

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Synthesis and characterization of elastoplastic poly(styrene-co-ethylene) using novel mono(?5-cyclopentadienyl) titanium and modified methylaluminoxane catalysts

Zhu¹,

Fang²,

Lin³

1999

J. Appl. Polym. Sci.

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Elastoplastic poly(styrene-co-ethylene) with high molecular weight was synthesized using novel mono( 5 -pentamethylcyclopentadienyl)tribenzyloxy titanium [Cp*Ti(OBz) 3 ] complex activated with four types of modified methylaluminoxanes (mMAO) containing different amounts of residual trimethylaluminum (TMA). The ideal mMAO, used as a cocatalyst for the copolymerization of styrene with ethylene, contains TMA approaching to 17.8 wt %. The oxidation states of the titanium-active species in different Cp*Ti(OBz) 3 /mMAO catalytic systems were determined by the redox titration method. The results show that both active species may exist in the current system, where one [Ti(IV)] gives a copolymer of styrene and ethylene, and the second one [Ti(III)] only produces syndiotactic polystyrene (sPS). Catalytic activity, compositions of copolymerization products, styrene incorporation, and copolymer microstructure depend on copolymerization conditions, including polymerization temperature, Al/Ti, molar ratio, and comonomers feed ratio. The copolymerization products were fractionated by successive solvent extractions with boiling butanone and tetrahydrofuran (THF). The copolymer, chiefly existing in THF-soluble fractions, was confirmed by 13 C-NMR, GPC, DSC, and WAXD to be an elastoplastic copolymer with a single glass transition temperature.

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Syndiotactic Polystyrene

Malanga¹,

Newman²

2001

Encyclopedia of Polymer Science and Technology

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Syndiotactic polystyrene is prepared from styrene monomer and organometallic catalysts. The material is a semicrystalline polymer with a crystallization rate high enough to make it practicable as an injection molding resin. The catalyst and polymerization chemistry is based on monocyclopentadienyl titanium complexes generally in combination with methylaluminoxane. The polymer has a melting point of 270°C with an excellent balance of processability, solvent resistance, and dimensional stability. The polymer can be filled with glass reinforcement, impact modified, and rendered ignition resistant, providing a new set of properties for the engineering plastics industry to use in electronic, automotive, electrical, and other market areas.

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Effects of residual and external alkylaluminum on the synthesis of syndiotactic polystyrene with cyclopentadienyltitanium tribenzyloxide-methylaluminoxane catalyst

Cited by 9 publications

References 13 publications

Polymerization of β‐pinene with Schiff‐base nickel complexes catalyst: Synthesis of relatively high molecular weight poly(β‐pinene) at high temperature with high productivity

Polymerization of β‐pinene with Schiff‐base nickel complexes catalyst: Synthesis of relatively high molecular weight poly(β‐pinene) at high temperature with high productivity

Synthesis and characterization of elastoplastic poly(styrene-co-ethylene) using novel mono(?5-cyclopentadienyl) titanium and modified methylaluminoxane catalysts

Syndiotactic Polystyrene

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