Review and Assessment of the Material’s Compatibility for Rubbers and Elastomers in Hydrogen Internal Combustion Engines

Hydrogen Internal Combustion Engines (H₂-ICEs) are being investigated due to their minimal criteria pollutant and zero CO₂ tailpipe emissions. However, oil filters and non-hot joint gaskets have rubber material that can be damaged and deteriorate due to direct or indirect exposure to the high temperature and high-pressure hydrogen in a H₂-ICE. Thus, the effects on the properties of a rubber exposed to a hydrogen environment need to be reviewed. In this review paper, the transportation, chemical and mechanical properties of a rubber exposed directly or indirectly to high temperature and high-pressure hydrogen in a H₂-ICE have been reviewed. The compatibility of rubber materials used in H₂-ICE has been explored. The effects of high-pressure hydrogen on the transportation, chemical and mechanical properties of NBR and HNBR have been reviewed. It is concluded that when the hydrogen pressure is less than or equal to 10 MPa the hydrogen infiltration of rubber remains linearly proportional to the pressure of hydrogen and above 10 MPa hydrogen pressure the content of NBR and EPDM is nonlinearly proportional to hydrogen pressures. The addition of Carbon Black (CB) in the NBR composites increases the hydrogen infiltration and its content due to the trapping of hydrogen by Carbon Black (CB). This article also proposes safe temperature and pressure ranges in which the rubber can be used without leading to fracture and deterioration. At the end of this article, future work for the use of rubber in H₂-ICE will be discussed.