Melt processable polyacrylonitrile copolymer precursors for carbon fibers: Rheological, thermal, and mechanical properties

Polyacrylonitrile (PAN) copolymers containing varying amounts of methyl acrylate (MA), P(AN-co-MA), were synthesized as a melt-spinnable precursor of carbon fibers. The rheological properties of P(AN-co-MA) with MA content of 15 mol% at 190 °C proved to be suitable for melt-spinning and the PAN fiber was spun from an extruder. In order to prevent remelting and fusion of the fibers in the stabilization process, electron-beam irradiation of over 1500 kGy was used and the melt-spun PAN fibers were successfully converted to stabilized PAN fibers by thermal treatment up to 250 °C. Finally, carbon fibers (CFs) were produced by pyrolysis of the stabilized PAN fibers. The mechanical properties of the resulting-CFs were evaluated; the tensile strength, tensile modulus, and elongation at break were 1.37 ± 0.2 GPa, 110 ± 11.1 GPa, and 1.27 ± 0.28%, respectively. These results suggest the possibility of utilizing melt-spinning as a cost-efficient method for fabrication of carbon fibers.