Ethylene/1-Hexene Copolymerization Kinetics and Microstructure of Copolymers Made with a Supported Metallocene Catalyst,Macromolecular Reaction Engineering

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Ethylene/1-Hexene Copolymerization Kinetics and Microstructure of Copolymers Made with a Supported Metallocene Catalyst
Macromolecular Reaction Engineering ( IF 1.8 ) Pub Date : 2021-11-01 , DOI: 10.1002/mren.202100041
Saeid Mehdiabadi ₁ , Olivier Lhost ₂ , Aurelien Vantomme ₂ , João B.P. Soares ₁

Affiliation

Ethylene/1-olefin copolymers made with supported metallocenes in slurry or gas-phase polymerization are often less homogeneous than those made with the same unsupported metallocene in solution polymerization. In particular, their molecular weight distributions are broader, having polydispersities higher than two, and sometimes their chemical composition distributions may even be bimodal. In our previous publication, we developed a mathematical model to describe the polymerization kinetics and polymer microstructure of ethylene homopolymers made with a supported metallocene catalyst. In this article, we extended that model to also cover the copolymerization of ethylene and 1-hexene with the same supported catalyst. The copolymerizations are performed in parallel semibatch reactors using a metallocene catalyst supported on an inorganic porous carrier. 1-Hexene concentration and polymerization time are the factors changed to investigate this system. Modeling results show that, as for the ethylene homopolymerization case, a three-site model is needed to describe the molecular weight distributions of the copolymers, but their chemical compositions can be described with a single set of reactivity ratios. A single set of parameters is also enough to describe the copolymerization kinetics with this supported catalyst. A new method is also developed and tested to estimate reactivity ratios under composition drift in this article.

中文翻译：

乙烯/1-己烯共聚动力学和用负载茂金属催化剂制备的共聚物的微观结构

在淤浆或气相聚合中用负载的茂金属制成的乙烯/1-烯烃共聚物的均相性通常低于在溶液聚合中用相同的未负载的茂金属制成的共聚物。特别是，它们的分子量分布更宽，多分散性高于两个，有时它们的化学组成分布甚至可能是双峰的。在我们之前的出版物中，我们开发了一个数学模型来描述用负载茂金属催化剂制成的乙烯均聚物的聚合动力学和聚合物微观结构。在本文中，我们扩展了该模型以涵盖乙烯和 1-己烯与相同负载型催化剂的共聚。使用负载在无机多孔载体上的茂金属催化剂在平行的半间歇式反应器中进行共聚。1-己烯浓度和聚合时间是研究该体系时改变的因素。建模结果表明，对于乙烯均聚情况，需要一个三点模型来描述共聚物的分子量分布，但它们的化学组成可以用一组反应率来描述。一组参数也足以描述这种负载型催化剂的共聚动力学。本文还开发并测试了一种新方法来估计成分漂移下的反应性比。对于乙烯均聚情况，需要一个三点模型来描述共聚物的分子量分布，但它们的化学组成可以用一组反应比来描述。一组参数也足以描述这种负载型催化剂的共聚动力学。本文还开发并测试了一种新方法来估计成分漂移下的反应性比。对于乙烯均聚情况，需要一个三点模型来描述共聚物的分子量分布，但它们的化学组成可以用一组反应比来描述。一组参数也足以描述这种负载型催化剂的共聚动力学。本文还开发并测试了一种新方法来估计成分漂移下的反应性比。

更新日期：2021-11-01

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