Acrylonitrile/Diallyl Phthalate Copolymer With Excellent Thermal Performance: A Potential Precursor for Carbon Fiber

ABSTRACT Polyacrylonitrile (PAN)‐based carbon fibers account for almost 90% of the total carbon fiber due to their excellent properties. However, PAN homopolymers have drawbacks such as a concentrated cyclization exotherm, numerous defects, poor flexibility, high tendency for filament breakage, and difficulty in spinning, all of which can seriously affect the quality and performance of the final carbon fibers. Herein, diallyl phthalate (DAP) is introduced as a comonomer to improve the thermal properties of PAN polymers. PAN homopolymers and the poly (acrylonitrile/diallyl phthalate) (P(AN‐DAP)) copolymers with different mass feed ratios were prepared via solution polymerization. The results show that, compared with PAN homopolymers, P(AN‐DAP) copolymers reduce the initial exothermic temperature, widen the exothermic range, and enhance the cyclization exotherm and the improvement of the cyclization degree. The introduction of DAP increases the crystallinity and thermal stability of the copolymers, with a carbon yield exceeding 50% at 800°C. Therefore, P(AN‐DAP) copolymer can be used as a potential carbon fiber precursor.