Polyacrylonitrile/carbon nanofiber nanocomposite fibers

Abstract Polyacrylonitrile (PAN)/carbon nanofiber (CNF) composite fibers have been processed with up to 30 wt% CNF using PAN polymers with molecular weights in the range of 100,000–700,000 g/mol. The composite fibers prepared from 20 wt% CNF and high molecular weight PAN polymer exhibit axial tensile properties that are typical of a textile fiber and in addition these fibers are also electrically conducting providing additional functionality (tensile strength of 0.31 N/tex, tensile modulus of 10.9 N/tex, axial electrical conductivity of 28 S/m). At high CNF concentrations (e.g. at 30 wt% CNF), CNF-rich and PAN-rich regions were observed in the fiber cross-section along with large elongated voids along the fiber axis. These factors negatively affect the tensile properties. All composite fibers exhibited an increased glass transition temperature ( T g ) by more than 15 °C along with a significant increase in storage modulus above T g as compared to the control fiber, suggesting good interaction between PAN and CNF.