Anqi Ju, Shanyi Guang, Hongyao Xu
Apr 1, 2013
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Influential Citations
121
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Quality indicators
Journal
Carbon
Abstract
Abstract In order to replace terpolymers with bipolymers, three bifunctional comonomers were synthesized to prepare poly(acrylonitrile-co-β-methylhydrogen itaconate) [P(AN-co-MHI)], poly(acrylonitrile-co-3-aminocarbonyl-3-butenoic acid methyl ester) [P(AN-co-ABM)] and poly(acrylonitrile-co-3-ammoniumcarboxylate-3-butenoic acid methyl ester) [P(AN-co-ACBM)] which can be used as carbon fiber precursor. The stabilization mechanism and effect of comonomer structure on the stabilization of bipolymers were studied by Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and thermogravimetry. Two parameters E s = A 1610 cm - 1 / A 2244 cm - 1 and SI = ( I 0 - I s ) / I 0 were defined to evaluate the extent of stabilization, and the activation energy (Ea) of the cyclization reactions were calculated by Kissinger method and Ozawa method. The results show that P(AN-co-MHI), P(AN-co-ACBM) and P(AN-co-ABM) exhibit better stabilization than terpolymers containing similar chemical composition, such as lower initiation temperature, larger extent of stabilization and smaller Ea. Furthermore, it is found that 3-ammoniumcarboxylate-3-butenoic acid methyl ester is the most effective one among the three comonomers for improving the stabilization of polyacrylonitrile (PAN) due to the strongest nucleophilicity of COO − NH 4 + towards the carbon atom of adjacent nitrile groups. Simultaneously, the rheological analyses show that all the three bipolymers possess better spinnability than PAN homopolymer.