State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan, 030001, China.
University of the Chinese Academy of Sciences , Beijing, 100039, China.
ACS Appl Mater Interfaces. 2016 Feb;8(7):4651-60. doi: 10.1021/acsami.5b11519. Epub 2016 Feb 10.
Anion exchange membranes (AEMs) based on 1,2,3-triazolium (TAM) were prepared from commercial poly(2,6-dimethyl phenylene oxide) (PPO) via "click chemistry" and subsequent N-alkylation. Flexible and tough membranes with various ion exchange capacities (IECs) were obtained by casting the polymers from NMP solutions. Although the resulting TAM-functionalized PPOs (PPO-TAM) membranes exhibited incomplete ion exchange in 1 M NaOH or NaHCO3 for 24 h even at elevated temperature, the highest hydroxide conductivities of the membranes were above 20 mS/cm at room temperature, which is comparable to many reported AEMs. Alkaline stability tests indicate that the PPO-TAM membranes showed a better alkaline stability than that of membranes containing imidazolium groups in 1 M NaOH at 80 °C, but still require further improvements in long-term stability for alkaline fuel cell application. An investigation of alkaline stability of model compounds demonstrated the instability of TAM cations under alkaline conditions could contribute to the deprotonation of benzylic methylene, C4 and C5 position on the triazolium ring. These results suggests that the alkaline stability of 1,2,3-triazolium cation could be improved by the introduction of substituents at the C4, C5 positions and benzylic methylene, and also provide insight and directions for organic cation designs for AEM application by the facile synthetic strategy of "click chemistry".
基于 1,2,3-三氮唑鎓（TAM）的阴离子交换膜（AEM）是通过“点击化学”和随后的 N-烷基化作用从商业聚（2,6-二甲基苯氧基）（PPO）制备的。通过将聚合物从 NMP 溶液浇铸，获得了具有各种离子交换容量（IEC）的柔性和坚韧的膜。尽管所得的 TAM 功能化 PPO（PPO-TAM）膜在 1 M NaOH 或 NaHCO3 中即使在升高的温度下 24 小时也不能完全离子交换，但膜的最高氢氧化物电导率在室温下超过 20 mS/cm，这与许多报道的 AEM 相当。碱性稳定性测试表明，与在 80°C 的 1 M NaOH 中含有咪唑鎓基团的膜相比，PPO-TAM 膜在碱性条件下具有更好的稳定性，但仍需要进一步提高长期稳定性，以用于碱性燃料电池应用。对模型化合物的碱性稳定性研究表明，TAM 阳离子在碱性条件下的不稳定性可能导致苄叉亚甲基、三氮唑环的 C4 和 C5 位置脱质子化。这些结果表明，通过在 C4、C5 位置和苄叉亚甲基上引入取代基，可以提高 1,2,3-三氮唑鎓阳离子的碱性稳定性，并且通过“点击化学”的简便合成策略，为 AEM 应用中的有机阳离子设计提供了见解和方向。
