Fatigue investigations of elastomers developed for high-pressure hydrogen gas environments

• Published in: International journal of fatigue 2024-12, Vol.189, p.108563, Article 108563
• Main Authors: Schieppati, Jacopo, Balasooriya, Winoj, Huber, Philipp Arno Franz, Pinter, Gerald
• Format: Article
• Language: English
• Subjects: Bound rubber; Elastomers; Energy dissipation; Fatigue; High-pressure hydrogen gas
• ISSN: 0142-1123
• DOI: 10.1016/j.ijfatigue.2024.108563

•Correlation of bound rubber content to fatigue and energy dissipation.•Coupling agent for silica-filled NBR decreases fatigue and increases bound rubber.•Additional CB to NBR leads to higher fatigue, energy dissipation, and bound rubber.•Peroxide-cured NBR showed high stiffness but low ultimate and fatigue properties.•Additional CB to EPDM leads to lower fatigue but similar dissipation and bound rubber. Hydrogen possesses many characteristics to be an ideal candidate as a more sustainable energy carrier, especially for the transport sector. For a proper optimization of this abundant resource, hydrogen needs to be compressed, and stored in high-pressure conditions, which demands improvement in technology and the development of appropriate materials. In this context, elastomeric sealing components play a critical role and they need to withstand harsh working conditions, for example, high-pressure, wide temperature range, cyclic exposure conditions, etc. In this work, eight different grades designed for this application were analyzed in terms of fatigue behavior and long-term performance. This was verified through fatigue crack growth experiments, the energy dissipation, and temperature increase during crack propagation were analyzed and correlated with micro-structural differences of materials. Furthermore, the materials were investigated at large and small deformations through uniaxial tensile tests and Dynamic Mechanical Analysis (DMA), respectively. It was found that only with the addition of a coupling agent can silica-filled NBR have properties similar to carbon black (CB) filled NBR, despite a reduction in both fatigue strength and energy dissipation. Coupling agents also involved an increase in bound rubber. Regarding CB-filled compounds, with peroxide crosslinking a reduction in fatigue strength was found, while no effect on the quantity of bound rubber was observed. Increased CB content in NBR grades led to decreased fatigue resistance and higher energy dissipation; higher bound rubber content was found as well. Also for EPDM grades, increased CB content resulted in reduced fatigue resistance. Despite an increase in energy dissipation, the content of bounded rubber was the same even with higher CB content.