Influence of PE/PP ratio and ENB content on the degradation kinetics of γ-irradiated EPDM

Different Ethylene Propylene Diene Monomers have been characterized prior and after aging under γ-irradiation. At small irradiation doses, the crosslinking process is the main mechanism occurring during irradiation, and is related to the residual ENB units remaining after the material processing. At higher doses, chain scissions (proportional to the radiation dose) are predominant and can be considered independent on the PE/PP ratio at a given ENB ratio, on the residual peroxide content, and on the initial EPDM cross-links density.