Assessment of percolation and homogeneity in ABS/carbon black composites by electrical measurements

In this study. composites consisting of an insulating poly(acrylonitrile-co-butadiene-co-styrene) polymer matrix and a conducting carbon black (CB) additive were produced by twin-screw extrusion. Both direct current and alternating current electrical measurements were used to evaluate the electrical properties of the composite and to assess whether sufficient mixing was achieved. Electrical measurement results and scanning electron micrographs show that once-extruded composites had a porous structure and poor conductivity while twice-extruded composites were much more homogeneous and had higher conductivity. The percolation threshold of the twice-extruded poly (acrylonitrile-co-butadiene-co-styrene)/CB composites was found to be between 8 and 10% CB. Electrical measurements provided a feedback loop for improving processing of the composite material. (C) 2003 Elsevier Ltd. All rights reserved.