In this work, two aromatic carboxylic acids (benzoic acid and isophthalic acid) are proposed to modify the permeability of poly(amide-b-ethylene oxide) or Pebax for CO₂ separation membranes. The effect of acid content on the gas separation performance of flat membranes was investigated using CO₂, CH₄ and N₂ at different pressures (4–10 bar) and temperatures (35–65 °C). The results show that both aromatic acids substantially improved the CO₂ permeability (about 120% above neat Pebax) due to the strong interaction between Pebax and the carboxylic groups of the acids, while CH₄ and N₂ permeability only slightly increase due to the restricted polymer chain mobility. This behavior led to enhanced CO₂/N₂ and CO₂/CH₄ selectivity by about 55% and 80%, respectively. Fourier transform infrared spectroscopy (FTIR) confirmed the coordinative interaction between the amide group of Pebax with the carboxyl functional group of the acids. The membranes thermal and mechanical stability were also determined by thermogravimetric (TGA and DSC) and dynamic mechanical (DMA) analyses. Finally, benzoic acid was found to be of interest since it contributed to superior thermal and mechanical strength as well as enhanced CO₂ separation properties.

在这项工作中，提出了两种芳香族羧酸（苯甲酸和间苯二甲酸）来改变聚（酰胺-b-环氧乙烷）或Pebax对CO ₂分离膜的渗透性。在不同压力（4-10 bar）和温度（35-65°C）下，使用CO ₂，CH ₄和N ₂研究了酸含量对平板膜气体分离性能的影响。结果表明，由于Pebax与酸的羧基，CH ₄和N ₂之间的强相互作用，两种芳族酸均显着提高了CO _2的渗透性（比纯Pebax高约120％）。由于受限制的聚合物链的迁移率，渗透性仅略有增加。该行为导致CO ₂ / N ₂和CO ₂ / CH _4的选择性分别提高了约55％和80％。傅里叶变换红外光谱（FTIR）证实了Pebax的酰胺基与酸的羧基官能团之间的配位相互作用。膜的热稳定性和机械稳定性也通过热重分析（TGA和DSC）和动态力学分析（DMA）来确定。最后，人们发现苯甲酸是令人感兴趣的，因为它有助于提高热和机械强度以及增强的CO ₂分离性能。