Vinyl‐type homo‐ and copolymerization of norbornene catalyzed by bis(phenoxyimine) titanium complex |
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Authors: | Jiafeng Meng Xin Li Xufeng Ni Zhiquan Shen |
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Affiliation: | MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China |
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Abstract: | A ternary catalytic system consisting of a bis(phenoxyimine) titanium complex, triisobutylaluminium and an organoboron compound exhibited high activity in the vinyl‐type homopolymerization of norbornene. The obtained polynorbornene showed a modest molecular weight (M n ≈ 5 × 104 g mol?1) and broad molecular weight distribution (polydispersity index ≈ 3.5). A copolymer of norbornene with 1,3‐butadiene was prepared using a binary catalytic system consisting of bis(phenoxyimine) titanium complex and triisobutylaluminium. The norbornene units in the copolymer adopted a vinyl‐type addition structure confirmed using distortionless enhancement by polarization transfer 135 13C NMR microstructure analyses. Polymerization kinetics studies showed that neither monomer feed ratio nor conversion had an effect on the composition of the copolymer backbone which was composed of 55% norbornene units and 45% 1,3‐butadiene units. The essentially constant polymer composition implied an alternating nature of chain propagation. The copolymer exhibited good thermal stability and moderate glass transition temperature (50.9–68.2 °C) with a relatively high molecular weight (M w = 0.18 × 10–1.31 × 105 g mol?1), and excellent transparency (maximal transmittance >80%). © 2017 Society of Chemical Industry |
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Keywords: | 1 3‐butadiene norbornene titanium complex alternating copolymer transparency |
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