Polymers for hydrogen infrastructure and vehicle fuel systems :

Abstract

This document addresses polymer materials for use in hydrogen service. Section 1 summarizes the applications of polymers in hydrogen infrastructure and vehicle fuel systems and identifies polymers used in these applications. Section 2 reviews the properties of polymer materials exposed to hydrogen and/or high-pressure environments, using information obtained from published, peer-reviewed literature. The effect of high pressure on physical and mechanical properties of polymers is emphasized in this section along with a summary of hydrogen transport through polymers. Section 3 identifies areas in which fuller characterization is needed in order to assess material suitability for hydrogen service.

An in situ tribometer for measuring friction and wear of polymers in a high pressure hydrogen environment

“…1,2 One common drawback of hydrogen, and especially at high pressure, is the potential for materials incompatibility. This is of critical concern to both refueling infrastructure [2][3][4] and onboard vehicle applications 5 where both metal and polymeric components are exposed to high pressure hydrogen, and in some cases, cyclic thermal and pressure variations that are likely to exacerbate the issue. Examples of polymer components include sliding seals in compressors and actuators, valves, regulators, and delivery hoses, all of which typically include some combination of metal and polymer materials.…”

Overview of the DOE hydrogen safety, codes and standards program, part 3: Advances in research and development to enhance the scientific basis for hydrogen regulations, codes and standards

“…Molecular hydrogen can generate non-reversible damage in elastomers, if the elastomer becomes super-saturated (e.g., during de-pressurization). Other hydrogen-induced phenomena, such as potential for plasticization in non-metals, have not been observed, but also have not been adequately studied [59]. In contrast, hydrogen tends to dissociate on metal surfaces, diffusing into the metal as a single atom.…”

An in situ tensile test apparatus for polymers in high pressure hydrogen

“…Operating at tens of MPa pressure compounds those issues and amplifies materials degradation issues. 2,3,14,15 We stress that proper safety precautions must be taken when working with high-pressure hydrogen, including, but not limited to: oxygen removal, appropriate hydrogen-safe materials, engineering assessments, high-pressure relief devices, and adequate venting for the hydrogen, which has potential to self-ignite under certain conditions.…”

“…This includes both structural polymers, such as high-density polyethylene (HDPE), and elastomers such as polyisoprene for uses in hydrogen storage and delivery, where pressures can reach between 35 and 70 MPa (5000 and 10 000 psi). [11][12][13] For example, structural polymers such as HDPE are used as liners in high-pressure type IV hydrogen tanks [11][12][13] and in pipelines, 14 while elastomers are used in valves, sliding seals, and other components 15 for high-pressure hydrogen. 16,17 Unlike the case with metals and piezoelectrics, where there is an abundance of information on the hydrogen degradation mechanisms, there is little information in the literature about the detrimental effects of hydrogen on polymers.…”

“…16,17 Unlike the case with metals and piezoelectrics, where there is an abundance of information on the hydrogen degradation mechanisms, there is little information in the literature about the detrimental effects of hydrogen on polymers. 15,[18][19][20] Hydrogen absorption in polymers differs from that of absorption in metals 3 in that very little, if any, disassociation is expected to occur within the material. Thus, the primary damage mechanisms in polymers are expected to be mechanical a) Author to whom correspondence should be addressed.…”