Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5201089 | Polymer Degradation and Stability | 2016 | 22 Pages |
Abstract
A series of polyacrylonitrile (PAN) polymers with different content of itaconic acid (IA) as comonomer were prepared by an efficient aqueous free-radical polymerization technique. The thermal behavior of the PAN polymers was investigated by simultaneous DSC/TG analysis. Effects of IA content, heating rate and atmosphere on the heat release and weight loss behaviors of the PAN polymers were studied for insight of the nature of the thermo-chemical reactions. A specific triple exothermic peak was observed in the DSC curves of P(AN-IA) copolymers in air atmosphere. Three individual exothermic peaks were obtained by peak fitting and assigned to the respective thermo-chemical reactions, namely, ionic cyclization reaction, free-radical cyclization reaction and oxidation reaction. The ionic cyclization reaction was significantly influenced by the IA content. The free-radical cyclization reaction was sensitive to heating rate and atmosphere. The cyclization reaction preceded the oxidation reaction and acted as a prerequisite for the oxidation reaction. The improvement of the thermal stability of PAN was mainly attributed to the oxidation reaction through dehydrogenation and formation of oxygen-bearing groups. Mechanisms of the thermo-chemical reactions were also proposed and discussed.
Related Topics
Physical Sciences and Engineering
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Authors
Qin Ouyang, Xiaohong Wang, Xulan Wang, Jing Huang, Xianwen Huang, Yousi Chen,