Electrically conducting systems based on polymers—I. Investigations of the structure of conductive systems based on uncured resins

Abstract

The great practical importance that electrically conducting polymeric materials have acquired in recent times has resulted from the setting up of a number of serious investigations of the factors determining the electrical conductivity of these materials. Systems based on vulcanizates have received most attention [1–7]. The effect of the structure of rubber vulcanizates on their dielectric properties has been demonstrated. It has also been found that the electrical conductivity of vulcanizates filled with carbon black is due to the formation of the particles of carbon black into chain structures. Different types of carbon black differ in the shape and size of the particles and in their tendency to form structures [8]. At the present time an ever widening circle of polymeric materials is being used for the production of electrically conducting systems. However, serious investigation of the conducting structures of materials based on synthetic resins has not yet been undertaken. In the present work a study was made of the structure of compositions consisting of phenol-formaldehyde resins of the resole type with various proportions of acetylene black, and of the epoxide resin E-40 also with various proportions of acetylene black. In order to facilitate the incorporation of the carbon black solutions of the resin were used, a 56% solution of the phenol-formaldehyde resin in alcohol and a 45% solution of the epoxide resin in acetone. The filler was added in small portions and ground with the solution in a mortar.