The link between swelling ratios and physical properties of EPDM rubber compound having different oil amounts

This new observation demonstrated that an increase in oil amounts within ethylene propylene diene monomer (EPDM) compounds decreased the crosslink density and the storage modulus but increase the elongation at break after tensile testing. The compounds with high oil amounts were observed to release oil particles when dissolved in toluene solutions and that increased their swell ratios. Consequently, the crosslink density had a perfect negative linear correlation with the elongation at break and a strong power-law correlation with the swell ratios. This work guides the material chemists and engineers during compound formulations when an increase in oil amounts is required.