Determination of permeation properties of hydrogen gas in sealing rubbers using thermal desorption analysis gas chromatography

Abstract

Permeation properties of hydrogen gas (H2) into nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), and fluoroelastomer (FKM) which are the strong candidates for sealing material in H2 energy infrastructures, was quantified using a thermal desorption analysis gas chromatography (TDA GC) and a self-developed diffusion-analysis program. The samples were charged with H2 in a high-pressure chamber for 24 h then decompressed into atmosphere, and the mass of H2 released from the sample was measured as a function of elapsed time after decompression. The developed program calculated the total charging amount C0 and diffusivity D, which were then used to calculate the H2 solubility S and permeability P for variation of pressure. The samples were polymerized with and without carbon black (CB) filler in cylindrical shapes with different diameters. There was no appreciable pressure up to 12 MPa or diameter dependence investigated in this study on D, S and P. NBR and EPDM showed dual hydrogen diffusion with fast and slow diffusion behaviors caused by CB, whereas FKM showed a single diffusion behavior. The determined D are Dfast, NBR = (1.55 ± 0.28) × 10–10 m2/s, Dslow, NBR = (3.1 ± 0.5) × 10–11 m2/s, Dfast, EPDM = (3.65 ± 0.66) × 10–10 m2/s, Dslow, EPDM = (3.3 ± 0.5) × 10–11 m2/s, DFKM = (7.7 ± 0.8) × 10–11 m2/s. It appeared that the filler contributes to increase S and decrease D. The uncertainty analysis against the evaluated data was carried out, too, in order that the method could be applicable as a standard test for the permeation properties of various polymer membranes.