Effect of foaming agent on the mechanical properties of sulfur and peroxide cured ethylene propylene diene monomer rubbers

Ethylene Propylene Diene Monomer 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 degrees K). Samples vulcanized by peroxide reveal more advantage over those 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.