Zhang Zhiqiang, Wu Qiao, Xu Shilin, Yue Zhongyuan, Zhou Haoli, Jin Wanqin
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, 5 Xinmofan Road, Nanjing 210009, PR China.
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, 5 Xinmofan Road, Nanjing 210009, PR China; Zhangjiagang Institute of Nanjing Tech University, Suzhou 215699, PR China.
J Hazard Mater. 2023 Oct 5;459:132151. doi: 10.1016/j.jhazmat.2023.132151. Epub 2023 Jul 25.
Microporous polymer membranes are promising candidates for industrial membrane-based gas separation because of their high separation performance. However, their relatively low stability due to the local rearrangement of polymer chains during usage remains a problem. Hence, we propose the construction of a fully aromatic polymer structure in a microporous polymer membrane to enhance membrane stability. Four triptycene-based microporous polyamides were synthesized via the polymerization of 2,6,14-triaminotriptycene with aromatic acyl chloride and/or aliphatic acyl chlorides. Their properties were characterized and compared by using nuclear magnetic resonance (NMR) and Brunauer-Emmett-Teller analyses. The synthesized polyamides were fabricated into composite membranes by employing a solution process; their stability was evaluated for the molecular sieving of nitrogen over volatile organic compounds such as cyclohexane. Low-field NMR and X-ray photoelectron spectroscopy were used to investigate the differences in the properties of membranes with different structures at different times. The results showed that the fully aromatic polyamide membrane made from 2,6,14-triaminotriptycene and aromatic acyl chloride displayed constant rejection (99 %) and nitrogen permeability (approximately 50 Barrer) for the molecular sieving of nitrogen over cyclohexane during 100-d experiments, indicating good stability. This approach paves the way for the industrialization of microporous polymer membranes from a theoretical perspective.
微孔聚合物膜因其高分离性能而成为基于膜的工业气体分离的有前景的候选材料。然而，由于在使用过程中聚合物链的局部重排，它们相对较低的稳定性仍然是一个问题。因此，我们提出在微孔聚合物膜中构建全芳香族聚合物结构以提高膜的稳定性。通过2,6,14-三氨基三蝶烯与芳香酰氯和/或脂肪族酰氯的聚合反应合成了四种基于三蝶烯的微孔聚酰胺。通过核磁共振（NMR）和布鲁诺尔-埃米特-泰勒分析对它们的性能进行了表征和比较。通过溶液法将合成的聚酰胺制成复合膜；对它们在氮气对环己烷等挥发性有机化合物的分子筛作用下的稳定性进行了评估。利用低场NMR和X射线光电子能谱研究了不同结构的膜在不同时间的性能差异。结果表明，由2,6,14-三氨基三蝶烯和芳香酰氯制成的全芳香族聚酰胺膜在100天的实验中对氮气对环己烷的分子筛作用表现出恒定的截留率（99%）和氮气渗透率（约50巴耳），表明具有良好的稳定性。这种方法从理论角度为微孔聚合物膜的工业化铺平了道路。
