A Reduced Third Order Markov Model for Ethylene‐Norbornene Copolymerization Kinetics with Homogeneous Metallocene Catalysts

Abstract

A reduced third order Markov model is presented to model the kinetics of ethylene‐norbornene copolymerization over rac ‐Et(1‐indenyl) 2 ZrCl 2 /methylaluminoxane catalyst in solution. In our previous work, we developed a penultimate model (second order Markov model) to describe the copolymerization rate behavior and the copolymer composition. Although the penultimate model provides better predictions of the polymerization kinetics than a simple terminal model, it tends to give underestimated norbornene incorporation rates at high norbornene/ethylene mole ratios in the bulk liquid phase. In this work, we propose a modified third order Markov model to improve the model's capability of calculating norbornene incorporation rate and comonomer sequence distribution. The model parameters have been estimated using a parameter optimization technique. The model simulation results indicate that the rate constant for norbornene insertion into a growing chain depends upon the norbornene microblock length at the propagating center. magnified image