Modeling of sequence length distribution for olefin copolymerization with vanadium-based catalyst |
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| Authors: | Xi-Pei Cheng Lian-Fang Feng Xue-Ping Gu Xi Chen Zhen-Guo Liu Kimberley B McAuley |
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| Affiliation: | 1. State key Laboratory of Chemical Engineering, Zhejiang University, Hangzhou, China;2. National Center for International Research on Quality-targeted Process Optimization and Control, College of Control Science & Engineering, Zhejiang University, Hangzhou, China;3. Research Institute of Jilin Petrochemical Company, PetroChina, Jilin, China;4. Department of Chemical Engineering, Queen's University, Kingston, Canada |
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| Abstract: | Some thermodynamic and mechanical properties of a polyolefin, such as the melting temperature and the rigidity, are dependent on the nature of its sequence distribution. Accurate modeling of sequence length distribution (SLD) is important in precisely tuning and optimizing the properties of polymers produced. In this article, we proposed a model to predict the molecular weight distribution (MWD) and SLD for olefin copolymerization with vanadium-based catalyst. Due to the 2,1-insertion of α-olefin with vanadium-based catalyst, the SLD is expressed by uninterrupted methylene sequence distribution instead of conventional triad sequence distribution. To obtain a reliable model, parameter estimation with experimental data is first conducted. The SLD model along with the estimated kinetic parameters can be used to predict unmeasurable sequence length fraction. For the experimental conditions studied, the average methylene sequence length is predicted to change from 10 to 4 units as the propylene/ethylene mole feed ratio increases from 1.1 to 3.4. |
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| Keywords: | kinetic parameter molecular weight distribution olefin copolymerization sequence length distribution |
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