Polarization and depolarization currents in carbon-black loaded polyolefins

摘要

In this paper the first results concerning an experimental investigation of the conduction mechanism in heat shrinkable carbon black-loaded polyolefins employed for stress relief in cable terminations has been presented. Both steady-state and transients conditions have been analysed. The dependence of isochronal currents on applied electrical field, electrode material and specimen dimensions indicates that the most probable predominant mechanism of conduction, at least for low values of the mean applied field, is represented by a diffusion limited single carrier transport. Space charge is also formed due to the structural characteristics of the composite. The obtained experimental results are congruent with theoretical findings reported in the literature. Moreover, the charging and discharging transient currents showing different values of the relevant exponents of the two power laws also support such inference.