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首页> 外文期刊>Journal of Applied Polymer Science >Synthesis and characterization of elastoplastic poly(styrene-co-ethylene) using novel mono(η~5-cyclopentadienyl) titanium and modified methylaluminoxane catalysts
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Synthesis and characterization of elastoplastic poly(styrene-co-ethylene) using novel mono(η~5-cyclopentadienyl) titanium and modified methylaluminoxane catalysts

机译：用新型单（η〜5-环戊二烯基）钛和改性甲基铝氧烷催化剂合成弹塑性聚苯乙烯-乙烯

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摘要

Elastoplastic poly(styrene-co-ethylene) with high molecular weight was synthesized using novel mono(η~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 13C-NMR, GPC, DSC, and WAXD to be an elastoplastic copolymer with a single glass transition temperature.
机译：用新颖的单（η〜5-五甲基环戊二烯基）三苄氧基钛[Cp * Ti（OBz）_3]配合物活化，并用四种类型的改性甲基铝氧烷（mMAO）活化，合成高分子量的聚苯乙烯-乙烯共聚物残留的三甲基铝（TMA）。用作苯乙烯与乙烯共聚的助催化剂的理想mMAO含有接近17.8 wt％的TMA。采用氧化还原滴定法测定了不同Cp〜* Ti（OBz）3 / mMAO催化体系中钛活性物质的氧化态。结果表明，两种活性物质都可能存在于当前体系中，其中一种[Ti（IV）]生成苯乙烯和乙烯的共聚物，而第二种[Ti（III）]仅生成间同聚苯乙烯（sPS）。催化活性，共聚产物的组成，苯乙烯的掺入和共聚物的微观结构取决于共聚条件，包括聚合温度，Al / Ti，摩尔比和共聚单体进料比。通过用沸腾的丁酮和四氢呋喃（THF）连续进行溶剂萃取来分馏共聚产物。通过13 C-NMR，GPC，DSC和WAXD证实主要存在于THF可溶级分中的共聚物是具有单一玻璃化转变温度的弹塑性共聚物。

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