CONDUCTION MECHANISMS IN SOME GRAPHITE-POLYMER COMPOSITES - THE EFFECT OF A DIRECT-CURRENT ELECTRIC-FIELD

This paper deals with the possible conduction mechanisms in highly ani sotropic composites comprising 0-10 vol% graphite Bakes within a polym er host. Conductivity measurements as a function of DC electric field have been made. In most cases, a non-linear behaviour of the current-v oltage relationships is observed. A number of theoretical models are c onsidered and we show that none of them is, by itself, able to explain our results. We further develop several arguments which lead us to co nsider the existence of a combined tunnelling effect and ionic conduct ion mechanism.