Space Charge and Dipolar Charge Contribution at Polar Polymers Polarization

The Thermally Stimulated Discharge Current (TSDC), the Final Thermally Stimulated Discharge Current (FTSDC), DC conductivity and the Final Thermally Stimulated Discharge Current with blocking electrode measurements were used to analyze molecules movement in Nylon 11. The objective was to discriminate between dipoles movement and space charge (SC) movement. The FTSDC method allows a better selection of the experimental conditions for sample charging (polarization). By decreasing the ratio between the charging time and the discharging time, the apparent peak is of the same order of magnitude as the genuine peaks and there is only a partial overlap between them. Even so, in Nylon 11 the SC-related processes are dominant in the temperature range from room temperature to 170 0 C. By using a Teflon-FEP blocking electrode, the space charge trapped in the sample is diminished significantly and the effects related to dipoles movement can be observed. Beside the two known peaks for Nylon 11, one associated with the glass transition around 60 °C and a second one associated with a molecular motion in the polycrystalline phase at 96 °C, a relaxation was observed around 168 0 C.