The thermochemical water-splitting iodine–sulfur (IS) process requires corrosion-resistant materials owing to usage of corrosive fluids, such as a mixture of HI–I₂–H₂O. Fluoropolymers, such as PTFE and PFA, are adaptable as lining materials for protecting plant components. However, there has been a concern: PTFE and PFA have the ability to permeate various permeants. From the viewpoint of corrosion of the base material, the permeation characteristics of HI and I₂ should be evaluated to improve the integrity of the IS process. In this study, permeation tests on PTFE and PFA membranes were performed to measure the permeated fluxes of HI and I₂, and the effects of the operating conditions on them were investigated. The introduction of a permeability parameter could be successful for normalizing the permeated fluxes for a specific membrane thickness and a vapor pressure. Then, the empirical formula of the permeability was given as an Arrhenius-type equation to use as a plant design. Finally, based on the results, the proper conditions for design of a lining material for the inhibition of HI and I₂ permeation are summarized.

由于使用腐蚀性流体（例如HI–I ₂ –H ₂ O的混合物），热化学水分解碘硫（IS）工艺需要使用耐腐蚀材料。含氟聚合物（例如PTFE和PFA）适合用作衬里保护植物成分的材料。但是，存在一个问题：PTFE和PFA具有渗透各种渗透剂的能力。从基材的腐蚀的角度出发，应评估HI和I ₂的渗透特性，以提高IS工艺的完整性。在这项研究中，对PTFE和PFA膜进行了渗透测试，以测量HI和I ₂的渗透通量。，并研究了操作条件对其的影响。渗透性参数的引入可以成功地针对特定的膜厚度和蒸汽压力归一化渗透通量。然后，将渗透率的经验公式作为Arrhenius型方程式给出，以用作工厂设计。最后，基于结果，总结了设计用于抑制HI和I ₂渗透的衬里材料的适当条件。