Gao Chang, Chen Hongzhi, Xu Hao, Wu Zhanjun, Dong Xufeng
School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China.
School of Aeronautics and Astronautics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024, China.
Polymers (Basel). 2025 Jun 25;17(13):1755. doi: 10.3390/polym17131755.
Liquid hydrogen (LH) storage using carbon-fiber-reinforced composite pressure vessels is facing increasing demands in aerospace engineering. However, hydrogen permeation in epoxy resin matrixes seriously jeopardizes the function and safety of the cryogenic vessels, and the micro-behavior of hydrogen permeation in epoxy resins remains mysterious. This study performed molecular dynamics (MD) simulations to investigate the hydrogen molecule permeation behaviors in two types of epoxy resin systems, with similar epoxy reins of bisphenol A diglycidyl ether (DGEBA) and different curing agents, i.e., 4,4'-diaminodiphenylmethane (DDM) and polypropylene glycol bis(2-aminopropyl ether) (PEA). The influencing factors, including the cross-linking degrees and temperatures, on hydrogen permeation were analyzed. It was revealed that increased cross-linking degrees enhance the tortuosity of hydrogen diffusion pathways, thereby inhibiting permeation. The adsorption characteristics demonstrated high sensitivity to temperature variations, leading to intensified hydrogen permeation at low temperatures. By triggering defects in the epoxy resin systems by uniaxial tensile simulation, high consistency between the simulation results and the results from helium permeability experiments can be achieved due to the micro-defects in the simulation model that are more realistic in practical materials. The findings provide theoretical insights into micro-scale permeation behavior and facilitate the development of high-performance epoxy resins in liquid hydrogen storage.
在航空航天工程中，使用碳纤维增强复合材料压力容器储存液态氢（LH）的需求日益增加。然而，环氧树脂基体中的氢渗透严重危及低温容器的功能和安全性，并且氢在环氧树脂中的渗透微观行为仍然未知。本研究进行了分子动力学（MD）模拟，以研究氢分子在两种环氧树脂体系中的渗透行为，这两种体系具有相似的双酚A二缩水甘油醚（DGEBA）环氧树脂主链和不同的固化剂，即4,4'-二氨基二苯甲烷（DDM）和聚丙二醇双（2-氨基丙基醚）（PEA）。分析了包括交联度和温度在内的影响氢渗透的因素。结果表明，交联度的增加会增强氢扩散路径的曲折度，从而抑制渗透。吸附特性对温度变化表现出高敏感性，导致低温下氢渗透加剧。通过单轴拉伸模拟在环氧树脂体系中引发缺陷，由于模拟模型中的微观缺陷在实际材料中更具现实性，因此模拟结果与氦渗透率实验结果具有高度一致性。这些发现为微观尺度的渗透行为提供了理论见解，并促进了液态氢储存中高性能环氧树脂的开发。
