Determination of activation energy of the relaxation time of the composite cellulose - synthetic ester with a high water content

The paper presents the results of the conductivity testing of Weidmann electrotechnical pressboard, with a moisture content of 5% by weight impregnated with MIDEL 7131 synthetic ester. Frequency and temperature dependencies of AC conductivity were determined on the basis of experimental results. The approximations of the frequency dependencies of conductivity were made with a step of 100 points per decade. The frequency dependencies of approximated conductivity waveforms at all measuring temperatures were shifted by means of the energy of activating the conductivity to a temperature of 293 K (reference temperature in electrical engineering). Arrhenius graphs were also drawn up, from which the energy activation of relaxation time and the value of the R2 determination coefficient for the selected conductivities were determined. Approximations of Arrhenius's graphs indicate high accuracy, as evidenced by the values of the coefficient of determination close to one. It has been found that the value of the activation energy of relaxation time varies within a very narrow range, which indicates that in the entire frequency range conduction is carried out according to the same mechanism - hopping conductivity.