The electrical characteristics of linear low density polyethylene degraded by the various aging factors

We have presented the effects of voltage-thermal and voltage-chemical aging of LLDPE on the conduction behavior, dielectric loss and AC breakdown strength. Any molecular structure changes are not observed in all the stressed LLDPE samples from FTIR analysis. From DSC measurement, we have observed that electrical stress assisted by thermal effect may cause the morphological changes, such as reorganization and degradation of crystalline, amorphous phase and their boundaries in the voltage-thermal stressed LLDPE. These morphological changes may be responsible for the increase of the detrapping or releasing of carriers and hopping through the amorphous phase in the voltage-thermal stressed LLDPE. Schottky process together with hopping may become dominant in the conduction behavior of long-term voltage-thermal stressed LLDPE(VT1100H). There are little superficial changes of morphology in voltage-chemical stressed LLDPE. A conduction mechanism of the voltage-chemical stressed LLDPE has not been changed significantly compared with that of virgin LLDPE. The different trends of increase or decrease of the dielectric loss and AC breakdown strength for the voltage-thermal and voltage-chemical stressed LLDPE may be due to the morphological changes.