New comonomer for polyacrylonitrile-based carbon fiber: Density functional theory study and experimental analysis.

Abstract Exploiting new comonomers is still required for high performance polyacrylonitrile (PAN) based carbon fiber. In this paper, we have proposed an efficient methodology, combining of theoretical calculation and experimental verification, to develop new comonomer for polyacrylonitrile (PAN)-based carbon fiber. The cyclization energy barriers of PAN copolymers, including comonomers of α-nitryl acrylic acid (IA-NO 2), α-amino acrylic acid (IA-NH 2), acrylamide (AAM), itaconic acid (IA), and ethylenesulfonic acid (ESA), have been calculated based on the autocatalytic cyclization mechanism using density functional theory (DFT) at B3LYP/6-31 + G (d, p) level. The theoretical calculation indicated that ionic cyclization of nitrile group was more easily initiated by ESA than other comonomers. Correspondingly, the PAN copolymers including comonomers of ESA and IA have been prepared and studied on their properties. The experimental results further demonstrated the P(AN-co-ESA) copolymer had better thermal properties such as smaller cyclization energy, slower heat release rate, and higher char yielding. Therefore, this theoretical calculation combined with experimental verification methodology is a powerful tool for exploiting new comonomer for PAN-based carbon fiber. Graphical abstract Image 1 Highlights • The cyclization energy barriers of selective comonomers were calculated via DFT. • The nitrile group is more easily initiated by ESA than the others by calculation. • The new comonomer of ESA containing sulfonic group has better thermal properties. • Combined theory and experiment are a useful methodology to exploit new comonomers. [ABSTRACT FROM AUTHOR]