Increase in Electrical Resistance of Rubber-Containing Epoxy Resin by Heat and Radiation

Rubber-containing soft epoxy resin, used as potting material in nuclear power plants, must exhibit good electrical insulation performance. Various simultaneous treatments with heat and gamma-ray irradiation were given to this resin, and leakage current, space charge distribution, glass transition temperature, elongation-at-break, and tensile strength were measured. It has become clear that the simultaneous treatment remarkably reduces the leakage current of the resin. This is because exposure to heat and radiation hardens the resin, inhibiting electrical conduction. Therefore, there is no need to worry excessively about resin aging.