Polyacrylonitrile/carbon nanofiber nanocomposite fibers

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 (Tg) by more than 15 °C along with a significant increase in storage modulus above Tg as compared to the control fiber, suggesting good interaction between PAN and CNF.