Suppressing high pressure hydrogen blistering in NBR via Zn-based MOF vulcanization: Microstructural and mechanical insights

Abstract

High-pressure hydrogen environments often lead to hydrogen-induced damages such as hydrogen blistering and cracking in rubber sealing materials, severely compromising the reliability of hydrogen energy equipment. Traditional rubber vulcanization activators, specifically zinc oxide (ZnO) aggregates, tend to cause hydrogen accumulation and expansion during depressurization, resulting in substantial hydrogen blistering damage. To mitigate the risk of hydrogen blistering formation in nitrile butadiene rubber (NBR), this study proposes using the zinc-based metal-organic framework (MOF) ZIF-8 as a multifunctional additive to replace ZnO. The effectiveness of ZIF-8 stems primarily from its hydrogen adsorption capability and enhanced interfacial bonding with the NBR matrix. Micro-CT and TEM analyses revealed that substituting additive with ZIF-8 significantly reduced initial defects through its enhanced interfacial bonding capability with the NBR matrix. Consequently, the blister volume fraction decreased by approximately 80 % compared to ZnO systems at equivalent content, with a notable reduction in average blister size. Moreover, ZIF-8 facilitated homogeneous silica dispersion and formed a denser crosslink network, increasing crosslink density by 25 % after high pressure hydrogen exposure. Mechanical tests indicated that ZIF-8 modified NBR exhibited a 20 % increase in tensile strength after hydrogen exposure, achieving a synergistic enhancement of hydrogen blistering resistance and mechanical stability. This work provides a scalable strategy for designing high-pressure hydrogen resistant elastomer composites, advancing reliable sealing solutions for hydrogen energy infrastructure.