Abstract:

The 1-decene was polymerized over metallocene catalytic system of rac-Et(1-Ind)₂ZrCl₂/C₆H₅NH(CH₃)₂B(C₆H₅)₄/ Al(i-Bu)₃, and the kinetics under various reaction conditions such as temperature and molar ratio of aluminum to zirconium was investigated. In order to obtain dynamic data for monitoring the reaction process, samples taken at different time were analyzed on monomer concentration by gas chromatograph (GC), and that on molecular weight of polymer by gel permeation chromatography (GPC). Based on the polymerization reaction mechanism and material balance, and the hypotheses for alkene polymerization, the kinetic model of the polymerization was established. The model includes the reactions of chain initiation, chain propaganda, chain transfer to monomer, chain transfer to active center and chain termination. Levenberg-Marquardt algorithm was used to optimize the model parameters. Through the model, the reaction rate, number-average and weight-average molecular weights and so on can be predicted. By the validation experiments it showed that the values of model prediction are very close to the experimental data. The model prediction showed that the chain initiation reaction process was completed in a few seconds, the chain propagation reaction has lower activation energy than the chain transfer reaction, and higher temperature is beneficial to the chain transfer reaction.

Key words: polymerization, kinetic, model, 1-decene, metallocene, organic boride

摘要：

以茂金属体系rac-Et（1-Ind）₂ZrCl₂/C₆H₅NH（CH₃）₂B（C₆H₅）₄/Al（i-Bu）₃催化1-癸烯聚合，对不同反应条件下（如温度，铝锆摩尔比）聚合反应动力学进行了研究。通过中间取样并利用GC测定单体浓度、GPC测定聚合物相对分子质量，获取动态的变化数据；结合聚合反应机理和物料平衡，对烯烃聚合反应做了一些假设，建立了聚合反应的动力学模型，该模型包括链引发、链增长、链转移至单体、链转移至活性中心和链终止几个反应。借助Levenberg-Marquardt算法对模型参数进行优化，通过该模型可以预测聚合反应速率、数均分子量和重均分子量等参数，验证实验结果表明模型预测值与实验数据相接近。模型显示链引发过程在几秒内完成，链增长反应相对于链转移反应具有较低的活化能，温度升高有利于链转移反应的进行。

关键词: 聚合, 动力学, 模型, 1-癸烯, 茂金属, 有机硼化物