Dielectric properties of electron beam irradiated polymer insulating material

Abstract

This study examined the influence of electron beam irradiation on the electrical properties of polyetheretherketone (PEEK) in terms of its conduction current, relative dielectric constant (/spl epsiv//sub r/'), relative dielectric loss factor (/spl epsiv//sub r/''), and thermally stimulated current (TSC). The temperature at which conduction current steeply increases shifted to higher temperatures with increasing exposure dose. Ion hopping distance (a) shortened with increasing exposure dose. The temperatures at which /spl epsiv//sub r/' and /spl epsiv//sub r/'' increase in the high temperature range shifted to higher temperatures with increasing exposure dose. Total charge (Q/sub TSC/) and activation energy (W) were derived from the TSC spectrum. As a result, Q/sub TSC/ increased with increasing exposure dose but gradually decreased for higher doses. On the other hand, H decreases with increasing exposure dose. From these results, it was found that electron beam irradiation brings about crosslinking and collapse at the same time in the amorphous region. The effect of crosslinking displays itself to a certain temperature. For higher temperatures, however, the collapse increases the number of carriers and this effect acts greatly.