Preparation and properties of low compression set conductive carbon black/silicone rubber composites

In order to obtain a conductive and electromagnetic shielding silicone rubber sealing material with low compression set and high resilience, a kind of conductive carbon black/silicone rubber composite based on methyl vinyl silicone raw rubber were prepared by filling carbon black treated by coupling agent as reinforcing agent and conductive fillers. The mechanical properties, elasticity, dispersity and electrical conductivity of these conductive carbon black/silicone rubber composites with different carbon black contents were investigated. The distribution morphologies of conductive carbon in silicone rubber matrix were characterized by SEM and the conductive and shielding mechanism of conductive carbon black/silicone rubber composites were analyzed. The results show that with the increasing of carbon black content, the Shore A hardness of conductive carbon black/silicone rubber composites increases from 31 to 70, the tensile strength first increases from 3.31 MPa to 5.28 MPa then tends to be steady, the elongation ratio first increases from 198% to 297% then decreases to 210%, while the constant compression set amount decreases first then increases and the instant rebound ratio decreases gradually. The conductive properties and shielding efficiency of conductive carbon black/silicone rubber composites improve promptly when "carbon black cluster" and the conductive road are established.