Modeling of Synthesis and Flow Properties of Propylene鈥揇iene Copolymers

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• 作者：Chinmay Das ; Daniel J. Read ; Johannes M. Soulages ; Pradeep P. Shirodkar
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：August 26, 2014
• 年：2014
• 卷：47
• 期：16
• 页码：5860-5868
• 全文大小：471K
• ISSN：1520-5835

文摘

Copolymerization with nonconjugated dienes offers an attractive route for introducing long-chain branching in polypropylene. From a simplified set of rate equations for such copolymerization with a metallocene catalyst, we derive the probabilities of branch formation at different stages of the reaction in a semibatch reactor. Using these probabilities, we generate an ensemble of molecules via a Monte Carlo sampling. The knowledge of the branching topology and segment lengths allows us to compute the flow properties of the resins from computational rheology. We compare our model predictions with existing experimental data, namely the molar mass distribution and small amplitude oscillatory shear response, for a set of resins with varying diene content. The rheology data suggest that the entanglement time 蟿_e depends sensitively and in a well-defined fashion on the diene content.