The suitable itaconic acid content in polyacrylonitrile copolymers used for PAN-based carbon fibers

This article was to provide some new insights into the influences of itaconic acid (IA) content in polyacrylonitrile (PAN) copolymers on polymerization, structural evolution, thermal behaviors and carbon yield relatively comprehensively. High IA containing poly(acrylonitrile-co-itaconic acid) (PAI) oligomers were successfully extracted from PAI copolymers with 2.0 and 3.0 mol % IA. PAI copolymers with 0.5 mol % and 1.0 mol % IA possessed more cyclized structures, conjugated carbonyl group, conjugated nitrile group, and less b-amino nitrile group as well as faster structural evolution rate than those of the other three PAI copolymers. Kinetic parameters indicated that excessive IA content in PAI copolymer did not have advantages in promoting cyclization reaction. The PAI copolymers with 0.5 wt % to 1.0 mol % IA possessed better crystalline parameters as well as higher carbon yield than those of the other two PAI copolymers after carbonization at 1350 degrees C. In summary, PAI copolymers with 0.5 mol % to 1.0 mol % IA will be more suitable for fabricating of high performance PAN-based carbon fibers. (C) 2016 Wiley Periodicals, Inc.