Relationships between properties and rapid gas decompression (RGD) resistance of various filled nitrile butadiene rubber vulcanizates under high-pressure hydrogen

We evaluated the crosslink density, permeability, tensile properties, hardness of NBR vulcanizates, featuring different fillers and contents, and correlated the properties of the filled nitrile butadiene rubber (NBR) vulcanizates with their resistance to rapid gas decompression (RGD). Also, we investigated the relationship between the relative change in the properties of filled NBR vulcanizates, induced by exposure to high-pressure hydrogen, and their RGD resistance. The crosslink density, tensile strength, hardness of filled NBR vulcanizates, the associated solubility coefficient, as well as the resistance of the filled NBR vulcanizates to high-pressure hydrogen increase with increasing filler content while the RGD resistance, elongation at break, permeability coefficient of the filled NBR vulcanizates, as well as the associated diffusivity coefficient of hydrogen decrease. These results indicate that the properties of NBR vulcanizates are closely related to their resistance to high-pressure hydrogen. The properties of filled NBR vulcanizates are impaired by exposure to high-pressure hydrogen, regardless of filler type and content, and the relative change in their elongation at break and volume is related to their RGD resistance. In addition, the properties and resistance to high-pressure hydrogen of HAF and silica-filled NBR vulcanizates are superior to those of MT-filled NBR vulcanizates. Therefore, HAF and silica-filled NBR vulcanizates are more suitable for application in high-pressure hydrogen facilities. Additionally, the compatibility of filled NBR vulcanizates can be estimated to some extent through relative change in elongation at break and volume resulting from exposure to high-pressure hydrogen.