Electrical conductivity of polyester resins doped with carbon black

The electrical conductivity of polyester resins cross‐linked with 5% of styrene and 45% of methyl methacrylate and doped with acetylene carbon black has been investigated. A high change of the electrical conductivity of the mixture was found at a critical content of carbon black ranging from 0.4 to 0.6 parts of carbon black per hundred parts of resin depending on the quantity and type of the cross‐linking agent used. The results obtained are in good agreement with the formerly interpretation of conductivity accepted for the mixture containing 55% of styrene.