Electrical Charge Injection/Ejection and Transport at Moderate Fields in Low-Density Polyethylene

The electrical conduction of LDPE was investigated in the temperature range from 20 to 95DGC and for applied fields up to 25 MV m-1, using isothermal charging and discharging currents measurements. The conduction process is strongly influenced by the charge stored in the sample. The apparent activation energy W is about 0.77 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.