INTERACTION OF HYDROGEN WITH FLUOROELASTOMER: SORPTION AND DEGRADATION

ABSTRACT Hydrogen (H 2 ) applications have received extensive attention for the preparation of energy transition. Thus, it is essential to understand H 2 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 H 2 in fluoroelastomers (FKMs) as well as its relation to molecular properties of the gas remain unclear. Hydrogen gas solubility in FKM as a function of pressure was carried out, and a linear relationship was observed that was consistent with Henry’s law. A correlation between the solubility coefficient of H 2 gas and critical temperature was quantitatively established. The temperature dependence of the solubility coefficient of H 2 in FKM at 3000 kPa and the correlation between heat of sorption and molecular properties of the gas were investigated. Furthermore, the diffusion coefficient and permeability coefficient of H 2 gas in FKM were systematically studied and compared with those of N 2 and CO 2 systems. Similarly, degradation of the FKM revealed that increasing aging temperature, aging pressure, and aging time have deleterious effects on degradation of FKM materials in hydrogen, more so than those in nitrogen. Spectroscopic analysis indicates abstraction of fluorine and crosslinking. Thus, this study enhances our current understanding of H 2 gas transport properties in FKM and degradation of FKM under high pressure and temperature and provides insight into elastomer performance under an H 2 environment to design superior formulations.