Copolymerization of Acrylonitrile/1-Vinyl-3-Ethylimidazolium Bromide and Rheological, Thermal Properties of the Copolymer
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Acrylonitrile(AN)/1-vinyl-3-ethylimidazolium bromide (VIMB) copolymer was prepared via solution polymerization using dimethyl sulfoxide (DMSO) as a solvent and azodiisobutyronitrile as an initiator. The effects of comonomer VIMB on the polymerization, rheological properties of the polymer solution and thermal properties of the copolymer were investigated. The ionic liquid VIMB resulted in higher polymerization conversion ratio and higher average molecular weight when copolymerized with AN than itaconic acid (ITA). Rheological measurements indicated that the transition shear rate increased linearly with increasing temperature for P(AN/ITA)/DMSO solution, while an exponential growth with temperature was observed for P(AN/VIMB)/DMSO solution. The exothermic peaks of DSC curves in N2 appeared at 276.67 and 257.34 °C for P(AN/VIMB) and P(AN/ITA), respectively. As a potential comonomer of AN for PAN carbon fibers, the VIMB resulted in about 7% higher char yield in N2, and 23.7% less weight loss at 600 °C in air than ITA copolymer.
KeywordsCarbon fiber Copolymer Polyacrylonitrile Ionic liquid Thermal properties
This work was supported by the National Natural Science Foundation of China (no.U1362205). The authors would like to acknowledge Professor Guibao Zhang at Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, for synthesizing and providing 1-vinyl-3-ethylimidazolium bromide.