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首页> 外文期刊>Journal of Applied Polymer Science >Full-range kinetic study on bulk syndiotactic polymerization of styrene with homogeneous metallocene catalysis
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Full-range kinetic study on bulk syndiotactic polymerization of styrene with homogeneous metallocene catalysis

机译：均相茂金属催化苯乙烯本体间同聚合的全过程动力学研究

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By choosing a proper agitator and reinforcing its stirring shear, powdery syndiotactic polystyrene (sPS) is prepared in a bulk precipitation process with two homogeneous metallocene catalyst systems [Cp*TiX3/'MAO/TIBA (X = Cl or OPhOMe)]. A full-range kinetics study of the heterogeneous polymerization is performed in detail to produce this kind of powdery sPS in an industrial process. A typical curve of conversion versus time takes an S shape and an obvious acceleration phenomenon occurs in the middle stage of the polymerization, although the polymer-monomer gel is avoided. The viscous-average molecular weight of sPS goes through a peculiar increasing-decreasing-increasing change during the bulk polymerization process. These phenomena are viewed in terms of the two-phase polymerization mechanism and the overheating in particles during polymerization. The influence of the metallocene catalyst type and concentration, MAO/Ti ratio, triisobutyl aluminum (TIBA)/Ti ratio, and polymerization temperature on the polymerization kinetics are investigated. TIBA has dual effects on the polymerization. A small amount of TIBA in the catalyst system promotes polymerization, but more TIBA leads to a low molecular weight sPS. (C) 2002 Wiley Periodicals, Inc. [References: 11]
机译：通过选择合适的搅拌器并增强其搅拌剪切力，可以在本体沉淀过程中使用两种均相茂金属催化剂体系[Cp * TiX3 /'MAO / TIBA（X = Cl或OPhOMe）]制备粉末状间同聚苯乙烯（sPS）。详细地进行了非均相聚合的全范围动力学研究，以在工业过程中生产这种粉状sPS。尽管避免了聚合物单体凝胶，但是典型的转化率随时间变化的曲线呈S形，并且在聚合的中间阶段出现明显的加速现象。在本体聚合过程中，sPS的粘均分子量经历独特的增加-减少-增加-改变。从两相聚合机理和聚合过程中颗粒过热的角度来看这些现象。研究了茂金属催化剂类型和浓度，MAO / Ti比，三异丁基铝（TIBA）/ Ti比和聚合温度对聚合动力学的影响。 TIBA对聚合有双重影响。催化剂体系中少量的TIBA促进聚合，但是更多的TIBA导致低分子量sPS。 （C）2002 Wiley Periodicals，Inc. [参考：11]

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