Impedance and modulus spectra of the percolation system silicon–polyester resin and their analysis using the two exponent phenomenological percolation equation

The ac conductivity of silicon–polyester resin composites is found to be best fitted using the two exponent phenomenological percolation equation (TEPPE) (formerly known as the general effective media (GEM) equation). The results show that, with the actual experimentally measured components’ electrical properties as input, the TEPPE can be used to model and fit the composites’ complex conductivity data. The paper also highlights the importance of using several representations of the immittance spectroscopy data in order to correctly identify the various contributions, for instance the modulus plots clearly show the arcs due to the isolated percolation clusters, below the critical volume fraction.