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Modeling and Experimental Evaluation of Single Particle Growth in Syndiotactic Polymerization of Styrene

机译:苯乙烯间同聚合中单颗粒生长的建模与实验评价

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摘要

A comprehensive mathematical model and experimental study of single particle growth for styrene polymerization over a silica-supported metallocene catalyst were investigated. The model was developed based on the modification of the well-known multigrain model (MGM) by introducing mesoparticle scale limitations. Thereafter, the model was employed to predict the effects of bulk phase temperature and catalyst properties (initial catalyst active site concentration and initial catalyst particle size) on the polymerization rate, degree of polymerization (DP), and the polydispersity index (PDI) of syndiotactic polystyrene (SPS). The simulation results showed a significant radial distribution of styrene concentration across polymer particle growth at different polymerization conditions. It was found that increasing the initial catalyst concentration and bulk phase temperature resulted in polymerization rate enhancement. In context, the polymerization rate decreased as the initial catalyst particle size increased from 20 to 50 μm. The results revealed that a uniform increase in DP of the polymer was obtained by increasing the initial catalyst concentration and the reaction temperature, while resulting in a decrease of the PDI value. Meanwhile, the DP and PDI values varied inversely under the influence of initial catalyst particle size within a period of time similar to the one needed in the catalyst decay. The simulated results in the study agree well with experimental data of SPS.
机译:研究了二氧化硅负载的茂金属催化剂上苯乙烯聚合的单颗粒生长的综合数学模型和实验研究。通过引入介观的颗粒尺寸限制,基于众所周知的多颗粒模型(MGM)的修改开发了该模型。此后,该模型用于预测本体相温度和催化剂性能(初始催化剂活性位点浓度和初始催化剂粒径)对间规聚合速率,聚合度(DP)和多分散指数(PDI)的影响聚苯乙烯(SPS)。模拟结果表明,在不同聚合条件下,苯乙烯浓度在整个聚合物颗粒生长中的径向分布显着。发现增加初始催化剂浓度和本体相温度导致聚合速率提高。在上下文中,随着初始催化剂粒度从20μm增加至50μm,聚合速率降低。结果表明,通过提高初始催化剂浓度和反应温度,聚合物的DP得到均匀增加,同时导致PDI值降低。同时,在与催化剂衰变所需的时间相似的一段时间内,在初始催化剂粒径的影响下,DP和PDI值成反比。研究中的模拟结果与SPS的实验数据非常吻合。

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