Dielectric characteristics of conductive carbon black filled ethylene-octene copolymer vulcanizates

Ethylene-octene copolymer (EOC) composites have been prepared by meltmixing method using different weight fraction (0-40 %) of ENSACO-250G carbon black. The dielectric relaxation behaviour of carbon black-filled ethylene-octene copolymer (EOC) nano-composites of different filler-loadings has been studied in a frequency range of 100 Hz to 5 MHz at room temperature. The variation in ac conductivity, dielectric permittivity, impedance and dielectric loss tangent (tand) has been studied as a function of carbon black loading and frequency. Interfacial polarization of the filler in the polymer matrix plays a key role for the variation of dielectric permittivity with filler loading. The calculated relaxation time for the first and second peaks of tand curve are found to be 1 7.6 mu s and 0.24 ae s respectively. The percolation threshold was observed at 30 phr carbon black loading. The Nyquist plot was also studied as a function of filler concentration.