Session: MF-02-01 Materials for Hydrogen Service-Polymers 1

Paper Number: 121918

121918 - In-Situ Wear Behaviors of Acrylonitrile Butadiene Rubber (Nbr) and Ethylene-Propyelen-Diene Monomer(epdm) in Low-Pressure Hydrogen Environments 

Hydrogen has emerged as a prominent eco-friendly energy source, and as fuel cell technology continues to advance, there are ongoing efforts to harness hydrogen as a sustainable fuel for various applications in both transportation and daily life. Over an extended period, hydrogen's inherent propensity to induce embrittlement in metallic materials has been well-documented. Consequently, substantial research has been dedicated to the phenomenon of hydrogen embrittlement, leading to the formulation of numerous hydrogen embrittlement theories over the years. Nevertheless, recent times have witnessed a surging demand for investigations related to the compatibility of hydrogen with non-metallic polymer materials. This demand has grown significantly, particularly in the context of applications involving high-pressure hydrogen environments, such as those found in hydrogen-powered electric vehicles and charging stations. These high-pressure hydrogen charging stations and hydrogen electric vehicles rely on a variety of rubber O-rings to effectively contain and prevent the escape of high-pressure hydrogen. However, it should be noted that O-rings deployed in these environments are subjected to a wide temperature range, spanning from -40°C to 85°C, which exposes them to extreme conditions. Moreover, the operation of fuel cell electric vehicles (FCEVs) introduces dynamic pressure fluctuations that may lead to repetitive O-ring slippage, ultimately contributing to wear and degradation. Previous research has illuminated the emergence of internal pores and cracks within rubber materials exposed to high-pressure hydrogen environments, accompanied by consequential alterations in their mechanical properties due to rapid decompression. Furthermore, other previous studies have highlighted variations in the in-situ friction wear behavior of NBR and EPDM in high-pressure hydrogen environments, revealing that the friction coefficient differs between a hydrogen atmosphere and an ambient air environment. However, research examining the friction wear behavior in diverse gas atmospheres remains limited. In this study, in-situ experiments were conducted within various gas atmospheres, encompassing ambient air, hydrogen at 5 bar, and helium at 5 bar. The goal was to systematically investigate the influence of hydrogen on the friction and wear characteristics of rubber materials. To achieve this, two commonly used rubber O-ring materials, NBR and EPDM, were enriched with equal proportions of carbon black and silica as fillers. The investigation then focused on evaluating the friction and wear properties contingent on the filler type and the nature of the rubber material. The findings unveiled distinctions in the friction wear behavior of rubber materials in low-pressure hydrogen environments, highlighting the critical influence of both the type of rubber material and the filler. The comprehensive analysis of the tribological properties of diverse rubber formulations in hydrogen environments holds the potential to significantly advance the development of sealing materials tailored for dependable performance in hydrogen-rich environments.

Presenting Author: Byeonglyul Choi Korea University

Presenting Author Biography: Byoenglyul Choi is currently Ph.D student in mechanical engineering at Korea university.
He has been conducting research on tribology of polymer materials used in high-pressure hydrogen environments and evaluation of the long-term lifespan and low-temperature sealing performance of O-rings used in hydrogen electric vehicle.

Authors:

Byeonglyul Choi Korea University
Un Bong Baek Korea Research Institute of Standards and Science
Byoung-Ho Choi Korea University