Abstract

Hydrogen (H₂) applications have received extensive attention for the preparation of the energy transition. Thus, it is essential to understand the H₂ gas transport properties in elastomers and degradation of elastomers under high pressure and high temperature. However, the effect of pressure on the gas sorption of H₂ in fluoroelastomers (FKMs) as well as its relation to molecular properties of the gas remain unclear. In this work, hydrogen gas solubility in FKM as a function of pressure was carried out and a linear relationship was observed consistent with the Henry’s Law. A correlation between the solubility coefficient of H₂ gas and critical temperature was quantitatively established. The temperature dependence of the solubility coefficient of H₂ in FKM at 3000 kPa as well as the correlation between heat of sorption and molecular property of the gas were investigated. Furthermore, the diffusion coefficient and permeability coefficient of H₂ gas in FKM were systematically studied and compared with those of N₂ and CO₂ systems. Similarly, degradation of the fluoroelastomer revealed that increasing aging temperature, aging pressure and aging time have deleterious effects on degradation of FKM materials in hydrogen, more than those in nitrogen. Spectroscopic analysis indicate abstraction of fluorine and crosslinking. Thus, this study enhances our current understanding of the H₂ gas transport properties in FKM and degradation of FKM under high pressure and temperature, and will provide us an insight into elastomer performance under H₂ environment to design superior formulations.