Electrical conduction of LDPE at moderate fields

The electrical conduction of LDPE was investigated. Results were obtained using isothermal charging and discharging currents, thermally stimulated charging and discharging current measurements. The conduction process is strongly influenced by the charge stored in the sample. The apparent activation energy W is about 0.70 eV. It changes with the isochronal measuring time and at low fields with temperature. As the applied field or charging time increase the space charge stored in the sample increases and implicitly W decreases. The results for long times (days) attest a new conduction mechanism: the space-charge-controlled conductivity.