Electrical Characterization of Polyester Reinforced by Carbon Black Particles

Abstract

Polymer matrix composite, based on Polyester reinforced with (0, 6, 12, and 18) % of carbon black has been prepared using solution cast technique. The dielectric constant and electrical conductivity of the samples are investigated in the frequency range ሺ0.5 െ1 0 ଷ ሻ ܭܪݖ and within the temperature range ሺ26 െ 80ሻ ௢ ܥ. Dielectric constant and loss tangent decreases with increasing frequency and increase with increasing temperature. The ac electrical conductivity ߪ ௔௖ for all samples were found to be weak frequency dependent at low frequency, however vary with frequency as a power law ௦ at higher frequency range. The exponential factor ݏ found to be in the range 0.65 ൏ ݏ ൏ 0.77. The weakly decreases of ݏ with increasing temperature, could be attributed that higher temperature, high mobility of free charges make them more frequency independent conductivity. From the temperature dependence of electrical conductivity, the activation energy at each frequency was calculated using the Arrhenius relation. The variation of the activation energy as a function of carbon black contents, and frequency is also discussed.