Electrical conductivity of prelocalized graphite-filled blend of polyvinyl chloride/styrene acrylonitrile composites in relationship to morphology and hardness

At present there is a greater need to design conducting polymeric composites that suit particular application with little compromise on mechanical properties. This work deals with the study of electrical conductivity and mechanical strength of graphite‐filled blend of polyvinyl chloride/styrene acrylonitrile (PVC/SAN) composites. Samples were prepared by prelocalization of graphite onto the particles of PVC and SAN with subsequent compression molding. At a fixed volume ratio of 1:1 of PVC/SAN, percolation threshold of 0.0063 volume fraction of graphite has been observed. SAN has improved the D‐shore hardness of composites. Composites with more than 3 wt% graphite content have good conductivity and still preserve a reasonable mechanical strength. Conductivity patterns suggest higher affinity of graphite for PVC as compared to SAN. Scanning electron microscopy (SEM) micrographs indicate the widening of graphite layers with increasing graphite content. The electrical conductivity of composites has been explained in terms of percolation theory. The universal exponent t is found to be 3.09 for a best‐fit value of percolation threshold of 0.0057 volume fraction of graphite. There is good agreement between calculated and experimental values. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)