Investigation of Physical and Mechanical Characteristics of Rubber Materials Exposed to High-Pressure Hydrogen

Abstract

Rubber materials play a key role in preventing hydrogen gas leakage in high-pressure hydrogen facilities. Therefore, it is necessary to investigate rubber materials exposed to high-pressure hydrogen to ensure operational safety. In this study, permeation, volume swelling, hydrogen content, and mechanical characteristics of acrylonitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), and fluorocarbon (FKM) samples exposed to pressures of 35 and 70 MPa were investigated. The results showed that the volume recovery and hydrogen desorption behavior of EPDM with the highest permeation were fast whereas those of FKM with the lowest permeation were slow. The volume of NBR with the highest hydrogen content expanded after decompression. In contrast, FKM swelled the most despite having the lowest hydrogen content. After exposure to high-pressure hydrogen, the compression set (CS) slightly increased due to internal cracks, but the tensile strength decreased significantly with increasing pressure despite the absence of cracks in the fracture area of all tensile specimens. It was concluded that the decrease in tensile strength is closely related to the volume increase because of the relationship between the relative true strength and the volume ratio.

Study on the expansion of nitrile rubber in high‐pressure hydrogen gas atmospheres: Calculations and experiments

“…The sealability of the O‐rings was tested at the inlet of the 70 MPa hydrogen tank. The volume expansion of the seal rings (Figure 3), due to hydrogen molecule permeation, was used to characterize the sealability of NBR 13 …”

“…The volume expansion of the seal rings (Figure 3), due to hydrogen molecule permeation, was used to characterize the sealability of NBR. 13…”

“…The sealing characteristics of NBR materials exposed to high‐pressure hydrogen have been extensively studied experimentally. The structure defects, such as the cracks under mechanical deformation, can induce the leakage of hydrogen 13 . The damages induced by rapid gas decompression (RGD) or explosive decompression (XDF) are common upon the sudden release of high‐pressure gas 14,15 .…”

“…The structure defects, such as the cracks under mechanical deformation, can induce the leakage of hydrogen. 13 The damages induced by rapid gas decompression (RGD) or explosive decompression (XDF) are common upon the sudden release of high-pressure gas. 14,15 RGD in the NBR can lead to the formation of submicron-scale voids or bubbles, and two phases with a clear interface between them.…”

Changes in the Optical Properties of Rubber Exposed to High-Pressure Hydrogen Using Pulsed Terahertz Waves

“…Hydrogen exposure analysis methods include thermal desorption spectroscopy [10], pressure composition isothermal (PCI) analysis [11], mass change analysis [12], hydrogen permeation testing [13], electron microscopy including the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods [14], spectroscopic analysis (Raman and FTIR) [15], and tensile testing [14]. Suitable assessment standards for rubber materials in high-pressure hydrogen environments are provided in the CSA/ANSI CHMC 2:19-2019 standard "Test methods for evaluating material compatibility in compressed hydrogen applications-Polymers" (abbreviated as CSA/ANSI CHMC 2) [16].…”