Influence of electro-thermal aging on the space charges measurements in epoxy resins

The role of space charges in the prebreakdown phenomena of polymers is commonly admitted and intensively studied. The behavior of space charges is quickly affected by aging and thus may lighten the influence of the various aging factors. The Laser Induced Pressure Pulse (LIPP) method has been mainly dedicated to the characterization of polyethylene materials submitted to DC voltage. Very few studies have concerned epoxy resins. The purpose of this study is to investigate how the LIPP method may be relevant in characterizing the aging under AC voltage and temperature of epoxy resins. This characterization may require the application of electrical fields and temperatures on the samples. However, it should not damage nor induce irreversible degradation of the tested samples whose aging should proceed. This possible degradation due to the measurements has first been studied using unaged samples submitted to various conditions of temperature, stress and duration of voltage application.