Polarization and thermally stimulated discharge current studies in cellophane thermoelectrets

Abstract Results of polarization and thermally stimulated depolarization studies in cellophane thermoelectrets for different polarizing conditions are reported in this paper. A method of separating the spontaneous current, for isolating the actual depolarization current, with the help of two different electrodes having a small difference in work functions, is given. Up to 10 kV/cm, the peak current and total charge increase linearly with field, indicating uniform polarization. Depolarization kinetic parameters, viz. activation energy, relaxation time, etc., for different polarizing conditions have been calculated both by initial rise and whole curve methods. A Bucci plot for the present results gives a straight line, indicating that a uniform process was operative during polarization or depolarization. Main chain scission and degradation starts at ⋍320°C. Apart from dipole orientation, charge/ion migration with subsequent trapping has been identified as the major component of polarization.