Analysis of the structure and properties of expanded graphite-filled poly(phenylene ether)/atactic polystyrene nanocomposite fibers

A miscible blend of 85.5 wt % atactic polystyrene and 9.5 wt % poly(phenylene ether) containing 5.0 wt % expanded graphite nanoparticles was melt-spun and stretched up to 25 times. The structure and electrical and mechanical properties of the fibers were investigated. Characterized by a Hermans orientation factor of 0.6, the nanographite platelets were moderately aligned with the fiber axis, which likely occurred when the polymer itself was partially aligned during drawdown. The electrical conductivity of the oriented filaments was about 10(-4) S/cm, about what other researchers have measured in comparable unoriented systems. The conductive network of agglomerated graphite nanoparticles did not collapse during drawdown, which led to small protrusions, or bumps, on the fiber surface. The obvious lack of polymer-particle bonding led to reduced extrinsic mechanical properties; both the tensile strength and elongation of the fibers were 20-25% less than those of the neat fibers. The modulus of the oriented fiber was unchanged by the addition of the graphite nanoparticles. (c) 2006 Wiley Periodicals, Inc.