Tailored filler-matrix interfaces for polymers in high-pressure hydrogen environments

For the use of elastomeric sealing materials in harsh conditions, e.g. high pressures and large temperature ranges, the type of rubber as well as the rubber reinforcement plays a critical role. Typically, silica or carbon black are used as reinforcing fillers. To further improve the material performance, especially regarding enhanced gas barrier properties versus permeat-ing hydrogen molecules, high aspect ratio filler with a tailored filler surface are suitable. Within this work, elastomeric grades with varying filler types were investigated, focusing on mechanical properties, high-pressure gas resistance, and morphology. Specifically, HNBR, NBR, and EPDM were examined. Further, the surface functionalization of high aspect ratio fillers, i.e. hexagonal boron nitride and graphite oxide, was studied. Finally, NBR rubber grades containing a hybrid filler system of carbon black and a platelet-shaped filler with a functionalized surface were comprehensively analyzed. The optimized hybrid filler grades with a tailored filler-matrix interface exhibit good mechanical properties along with suitable resistance against high-pressure gas and improved hydrogen transport properties, i.e. lower H2 permeability.