Retardation effect of additives on radiation degradation of EPDM

The authors describe the results of experiments in which aromatic oil, antioxidant, and ultraviolet-light absorber were individually added in order to examine their retarding effect on the radiation degradation of flame-retardant nonhalogen EP (ethylene-propylene) rubber compound. In addition, an electric wire was prepared using the material with the highest radiation resistance and its properties were examined. Test specimens with an addition of a 4.2 wt.% mixture of diaryl-p-phenylenediamines showed an elongation value of more than 50% after 10-MGy irradiation. When it is irradiated in air, the polymer is decomposed and oxidized; the degree of oxidation is more significant near its surface. This degradation of polymer, however, can be suppressed with the addition of antioxidant