We report a kinetic model of chain-shuttling copolymerization using dual catalysts for solution α-olefin polymerization processes. This model focuses on predicting polymer properties such as the molecular weight and molecular weight distribution and the overall copolymer composition. We first validate the model through qualitative comparison between the model predictions and experimental observations reported in Arriola et al. (Science) in both a semibatch reactor and a continuous stirred-tank reactor (CSTR). Then, examples are given to illustrate how the model can be used to examine the effects of the chain-shuttling rate constant and the chain-shuttling-agent feed rate in a CSTR. Moreover, simulations using this model demonstrate how to prepare polymers with desired properties by manipulating catalyst compositions and monomer compositions in the feed.

We report the theoretical derivation of a kinetic model for the prediction of average block structures such as number-average blocks, average block length, and average number of linkage points per chain, etc., in chain shuttling polymerization in the presence of dual catalysts based on the proposed mechanism. We further investigate how the chain shuttling rate constant and virgin chain shuttling agent (CSA) feed rate affect the average block structures predicted by this theoretical model for polymers produced in a continuous stirred tank reactor (CSTR). The simulations demonstrate that the coordination of dual catalysts and CSA is the key to enabling a successful chain shuttling polymerization system.

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