Effect of carbon black on the thermoelectrical properties of poly(ethylene-oxide) composites

Abstract

The AC electrical conduction and thermal conductivity of casted thin films of poly (ethylene oxide)/carbon black composites were investigated as a function of applied frequency in the range from 100 Hz to 5 MHz, temperature and carbon black concentrations 0, 1, 2, 4, 6, 8 and 10% by weight. The average films thickness was about 90 µm. The AC conductivity and dielectric properties were determined from impedance measurements. The study showed that the thermoelectrical properties are affected by adding carbon black filler into the poly (ethylene oxide) polymer matrix. The study observed that the dielectric constant and dielectric loss decrease with frequency, and increase with temperature, and carbon content. The AC-conductivity increases with increasing frequency, temperature and carbon black content. The observed percolation threshold of the AC-conductivity occurs at about 2 wt% carbon black concentration. The thermal conductivity of the prepared films was studied as a function of temperature and CB concentration. It was found that the thermal conductivity is enhanced by addition of the carbon black content and increasing temperature. In case of raising the temperature, the phonons are activated and electrons hopping to higher energy states, thus enhancement in the thermal conductivity is produced.