| Abstract: | The effect of physical ageing on the electrical properties, such as thermally stimulated discharge currents (TSDC) and conduction currents, of ethyl cellulose (EC) has been analysed. The TSDC thermograms of EC samples, poled with 100kVcm-1 at different poling temperatures (i.e. 50, 70 and 90°C) consist of two peaks located at 70±5°C and 110±5°C, respectively. The conductivity measurements were made over a time period of 101–103min in the temperature range 30–125°C with a poling field of 100kVcm-1. It has been observed that physical ageing considerably affects the magnitude of the thermally stimulated depolarization and conduction currents of EC films. This ageing effect, which has been attributed to continuous vitrification of a polymer, is considered to enhance the life-time of a polymer electret. © of SCI. |
