Absorption and polarization currents in aromatic polyamides

Abstract

Aromatic Polyamide (Trade Name Nomex type 410) is a high temperature dielectric which has many potential engineering applications. In this study charging, discharging and thermally stimulated polarization (TSP) currents are measured over a wide range of electric field strengths and temperatures. The influence of electrode materials and rate of heating on the TSP currents investigated for 127 /spl mu/m and 76 /spl mu/m thick paper. The results show that the observed current during charging and discharg are dissimilar and both decay according to I(t) = A t/sup -n/ where t is the time and n is the decay constant. The absorption currents are used to derive the low frequency dielectric properties of the material. The TSP current is observed to be dependent on electric field and heating rate. Possible mechanisms are discussed.