Abstract

This study evaluates the effects of silica surface area and loading on the hydrogen resistance and mechanical stability of ethylene propylene diene rubber (EPDM)/silica composites for advanced sealing applications. EPDM was compounded with silica grades ranging from 55 to 225 m2/g at 30, 50, and 70 phr. After peroxide curing, the specimens were exposed to 96.3 MPa hydrogen at room temperature for 24 h. Properties including hydrogen permeability, swelling, mechanical strength, dynamic modulus, and hysteresis were examined. The composite containing 50 phr of high-surface-area silica (225 m2/g) exhibited the optimal balance of low permeability, reduced swelling, and stable mechanical response. By contrast, 70 phr loading caused aggregation and strength loss. These results indicate that optimizing the filler surface area and content is critical in designing EPDM composites for hydrogen-sealing applications.

Keywords: nanocomposites, high-pressure hydrogen exposure, hysteresis loss, dynamic mechanical analysis, chain mobility