使用甲基环己基二甲氧基硅烷(C-donor)作为外给电子体,对聚丙烯DQC球形催化剂进行了预接触温度液相本体聚合研究.实验结果表明,预接触温度升高,DQC球形催化剂的聚合活性降低,得到聚合物的等规指数升高,熔融指数下降,得到的聚合物细粉含量增加.GPC测试结果表明,预接触温度升高,聚合物的分子量分布变宽,数均分子量和重均分子量降低.DSC测试结果表明,聚合物的熔融温度、熔融焓和结晶焓数值均有不同程度的提高,聚合物的结晶度提高.13C NMR测试结果表明,预接触温度升高,得到的聚合物全同立构三单元组mm序列结构和五单元组mmmm序列结构含量均增加.%The pre-contact temperature of DQC catalyst system on liquid bulk polymerization of propylene was studied using cyclohexyl methyl dimethoxy silane (C-donor) as external donor. The results indicated that increase of pre-contact temperature caused decrease of polymerization activity of DQC catalyst, which yielded polymers with decreased melt index but increased isotactic index and fine powder content. Gel permeation chromatography (GPC) results showed that increase of pre-contact temperature broadened molecular weight distributions and decreased both number and weight average molecular weights. Differential scanning calorimetry (DSC) results exhibited that melting temperature, melting enthalpy, crystallization enthalpy, and crystallinity of polypropylenes increased to various degrees.13C NMR results showed an increase of stereoregular sequences of triad mm and pentad mmmm with increase of pre-contact temperature.
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