Conductive elastomer composites with low percolation threshold based on carbon black and epoxidized natural rubber

Conductive elastomer composite based on carbon black (CB) filled epoxidized natural rubber with 50 mol% epoxide (ENR‐50) were prepared using two types of CB: high abrasion furnace (HAF) and extra conductive furnace (ECF) with different loading levels. It was found that the ENR‐50/ECF composite had the maximum tensile strength at lower loading of 10 phr as compared with the ENR‐50/HAF composite at 20 phr. Furthermore, the Kraus's relation revealed that two types of CB provide different degree of reinforcement. Incorporation of CB leads to increase permittivity, loss factor and conductivity of the composites. However, the ENR‐50/ECF composites show higher conductivity than that of the ENR‐50/HAF composites. The electrical percolation thresholds (p_c) of ENR‐50/HAF and ENR‐50/ECF composites were observed at loading levels of CB = 12.0 and 6.3 vol%, respectively. These are very low percolation thresholds of the conductive elastomer composites with CB. POLYM. COMPOS., 39:1835–1844, 2018. © 2016 Society of Plastics Engineers