Dielectric properties of ethylene-propylene rubber in cryogenic temperature region

Abstract

The effect of additives such as crosslinking agent and fillers on tan /spl delta/ of ethylene-propylene rubber (EPR) was examined at temperatures between 4.2 K and 300 K. Thickness dependence of tan /spl delta/ was also evaluated by using EPR films of different thickness and an extruded EPR insulated cable sample. The results show that additives increase tan /spl delta/ of relatively thin EPR films even in cryogenic temperature region, whereas the thicker samples practical to cable insulation do not give intolerable dielectric loss. The remedy to tan /spl delta/ increase due to the polymer contraction relative to shielding wires has been established.<>