Polyacrylonitrile/vapor grown carbon nanofiber composite films

Polyacrylonitrile (PAN)/vapor grown carbon nanofiber (VGCNF) composite films were processed from N, N-dimethylformamide (DMF) at various nanofiber loadings: 5, 10, 20, 40, 60, 80, and 90 wt%. Tensile, dynamic mechanical, electrical, structural, and morphological properties of these composite films were studied. Enhancement in tensile properties was observed in composites with nanofiber loading up to 40 wt%. The storage modulus of PAN increased upon incorporation of nanofiber particularly above the glass transition temperature. The tan δ peak broadens and shifts to higher temperatures with the addition of VGCNF. The activation energy for PAN molecular motion was higher than that in the control PAN film. The electrical conductivity of composite films increased with increasing nanofiber loading and exhibited a percolation at 3.1 vol%. Scanning electron microscopy (SEM) indicated PAN coated nanofibers in the composite film.