Effect of foaming agent on the mechanical properties of sulfur and peroxide cured Ethylene Propylene Diene Monomer rubbers

EPDM rubbers loaded with different concentration of azodicarbonamide as a foaming agent using two different cross-linking systems were subjected to the mechanical, compression and swelling tests at room temperature (300°K). Samples vulcanized by peroxide reveal more advantage over that vulcanized by sulfur especially for the amount of specific gravity and the compression test. The tensile test shows a noticeable increase in the true stress and strain at break for the sulfur cross-linking system than the peroxide one. For the swelling test, the empirical equation used by Kumnuantip and Sombatsompop shows the best fitting for the degree of swelling – time data.