Poly(acrylonitrile-co-2-methylenesuccinamic acid) as a potential carbon fiber precursor: preparation and stabilization

A novel bifunctional comonomer 2-methylenesuccinamic acid (MLA) was synthesized to prepare poly(acrylonitrile- co -2-methylenesuccinamic acid) [P(AN- co -MLA)] copolymers, which can improve the stabilization of polyacrylonitrile significantly as a carbon fiber precursor. The structure and stabilization of P(AN- co -MLA) copolymers with different monomer feed ratios of AN/MLA were characterized by elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Reactivity ratio studies shows that MLA possesses higher reactivity than AN, resulting in higher MLA content in P(AN- co -MLA) copolymers than in the feed. The molecular weight and conversion of copolymer decrease gradually with the increase of MLA content in the feed. Comparing with PAN homopolymer, P(AN- co -MLA) copolymer has two or even three exothermic peaks, and the initial temperature of P(AN- co -MLA) copolymer is ca. 70 °C lower than that of PAN, which broadens the exothermic peak. The Δ H /Δ T reduces from 34.01 J g −1 °C −1 to less than 17.67 J g −1 °C −1 , confirming that the incorporation of MLA can avoid centralized heat release effectively. In addition, the extent of stabilization increases as the MLA content in P(AN- co -MLA) copolymer increases under the same heat treatment conditions. The activation energy ( E a ) calculation shows cyclization E a of P(AN- co -MLA) reduces from ca. 168 kJ mol −1 to ca. 110 kJ mol −1 , it is concluded that synthesized comonomer MLA can significantly improve stabilization of PAN, which is conducive to the preparation of high performance carbon fiber. A bifunctional comonomer was synthesized to prepare polyacrylonitrile- co -(2-methylenesuccinamic acid) copolymer, which can improve the stabilization of polyacrylonitrile as carbon fiber precursor.