Electrical properties of polyolefin blends under γ-radiation exposure

Polymer dielectrics: low density polyethylene (LDPE), high density polyethylene (HDPE), previously degraded polypropylene (dPP) and ethylene-propylene terpolymer (EPDM) were investigated after γ-irradiation in air. Changes in electrical properties: volume resistivity, dielectric constant and dielectric loss, were determined for ethylene-propylene terpolymer and degraded polypropylene blends containing 0, 20, 40, 60, 80 and 100 phr of polypropylene. The contribution of each component to the evolution of electrical parameters is discussed. While virgin polyolefin blend samples present a steady state in electrical resistance on time, the irradiated compounds containing degraded polypropylene trend to a continuous increasing values of resistivity. The presence of oxygenated compounds in the radiation modified samples leads to the decrease in volume resistivity. The comparative behaviour of polyolefin blends shows that the blend containing ethylene-propylene elastomer and low-density polyethylene has electrical features between the other two mixtures.