Electrical Conduction Mechanisms in Synthesized Ethylene Propylene Diene Monomer Rubber Loaded with High Abrasion Furnace Carbon Black

Ethylene Propylene Diene Monomer (EPDM) rubber filled with High Abrasion Furnace (HAF) carbon black at various concentrations (30, 40, 50, 80 phr) were synthesized and electrically characterized. The structure of the synthesized EPDM/HAF composites was studied by XRD and the surface morphology was analyzed by SEM. The XRD patterns revealed that the structure was partially amorphous with some crystalline phases. SEM micrographs showed a set of carbon black aggregates with different dimensions depending on the amount of carbon black filler. The electrical resistivity (conductivity) of the composites was investigated as a function of temperature and filler content. The electrical conductivity was greatly influenced by both the temperature and carbon black filler content. The conduction mechanisms were analyzed at different temperature regions. A variable range hopping process was suggested to explain the temperature dependence of the conductivity of low mass fraction carbon black. At higher carbon black concentration, the behavior of the conductivity is of a semiconductor-like and a metallic-like behavior. The concept of metal- insulator transition was suggested to explain the conductivity of the composites.