A tritium tracer technique for the measurement of hydrogen permeation in polymeric materials

Hydrogen permeation data are of interest in the selection of new materials in hydrogen fuel cell systems and water electrolyzers. Arrhenius type relations for the permeation and diffusion of hydrogen in polymers are determined using tritium as a radiotracer. Hydrated tritium, HT, in an H2/HT gas stream is measured by an ionization chamber tritium detector and an HTO water trap. Permeation and diffusion coefficients and, their respective activation energies are determined using the time lag method for Viton, Teflon, EPDM, Santoprene and Noryl. The measurements are consistent with earlier investigations, where polymers with higher glass transition temperatures exhibit lower permeation and diffusion coefficients. This study provides insight for choosing fuel cell materials for cell operating temperatures within 25 < T < 150°C.