模拟PEM燃料电池环境下垫片材料的化学损伤研究

STUDY ON CHEMICAL DEGRADATION OF GASKET MATERIAL IN SIMULATED PEM FUEL CELL ENVIRONMENTS

对暴露在模拟质子交换膜(PEM)燃料电池环境下的硅橡胶弹性体垫片材料的化学损伤情况进行探究。采用平衡溶胀法测定试样暴露在模拟PEM燃料电池环境下交联密度的变化情况。采用衰减全反射傅里叶变换红外光谱(ATR-FTIR)和X射线光电子能谱(XPS)对老化试样表面的化学成分进行研究。实验结果表明,试样在加速持久性实验(ADT)溶液中交联密度明显降低,在常规(RS)溶液中变化不明显。ATR-FTIR和XPS实验结果表明,在模拟燃料电池环境下,试样表面分子结构随暴露时间发生明显变化,试样表面化学损伤加剧。材料的化学损伤主要表现为硅橡胶主链的断裂和高分子交联区的水解。

Chemical degradation of silicone rubber gasket material was investigated in simulated PEM fuel cell environments.The Equilibrium swelling method was used to measure the change of cross-linking density after the samples exposed to the simulated PEM fuel cell environment. Attenuated total reflection Fourier transform infrared(ATR-FTIR)spectroscopy and X-ray photoelectron spectroscopy(XPS)were used to study the surface chemistry change of aging specimens. The test results reveal that the cross-linking density of the samples in accelerated durability test solution were obviously decreased,but the change of the cross-linking density of the samples in regular solution is not obvious. ATR-FTIR and XPS results indicate that the molecular structure of the surface has changed and the chemical degradation on the surface increased after the samples exposed to simulated PEM fuel cell environment over time. The chemical degradation of the material mainly manifests as the main chain scissoring in the backbone of silicone rubber and de-crosslinking through hydrolysis of crosslink sites.