Influence of high field and molecular effects on some electrical properties of polymers

The influence of the strain energy on high field electrical aging of polyethylene and various other polymers is briefly reviewed. It appears that molecules strained by high fields store a significant energy and this modifies the endurance characteristics. An equation adding this term to the energy dissipated by the Maxwell stress describes very well the electrical aging of several polymers. Difficulties in interpreting the experimental data are indicated. It is also shown that the bonds breaking and straining processes present in aging are also affecting various other electrical properties. Several examples are shown were original interpretations based on Poole-Frenkel, Schottky or space-charge-limited current theories could as well be better fitted by the model presented here. In other words, it might be possible that charge transport in polymers is also dependent on bonds breaking at moderate stresses and bonds straining at high stresses.