Yao Dan, Wei Tonghui, Shang Lichao, Na Hui, Zhao Chengji
Alan G. MacDiarmid Institute, College of Chemistry, Jilin University Changchun 130012 P. R. China
School of Mechanical and Aerospace Engineering, Jilin University Changchun 130025 P. R. China.
RSC Adv. 2019 Mar 11;9(14):7975-7983. doi: 10.1039/c8ra09840a. eCollection 2019 Mar 6.
Anion exchange membranes based on side-chain-type quarternized poly(ether ether ketone)s (QPEEKs), containing different hetero-cycloaliphatic quaternary ammonium groups, were prepared a multi-step procedure, including polycondensation with a monomer containing pendant methylphenyl groups, bromomethylation, and followed by quaternization with 1-methylpyrrolidine (MPY), 1-methylpiperidine (MPRD), 1-methylimidazole (MIDZ) and -methyl morpholine (MMPH), respectively. The properties of these membranes were then compared with the properties of conventional quarternized poly(ether ether ketone)s containing benzyltrimethylammonium (QPEEK-TMA). Model compounds, QMPY, QMPRD, QMIDZ and QMMPH, were synthesized and used to quantitatively compare the alkaline stability of hetero-cycloaliphatic quaternary ammonium groups using H NMR. The results of this study indicated that the alkaline stability of all these model compounds is in the order of QMPY > QMPRD > QTMA > QMIDZ > QMMPH. These QPEEKs membranes display superior thermal, dimensional and mechanical stability. QPEEK-TMA, QPEEK-MPY and QPEEK-MPRD exhibit higher hydroxide conductivities and lower activation energies than QPEEK-MIDZ and QPEEK-MMPH. Furthermore, after exposure to 1 M NaOH at 60 °C for 24 days, QPEEK-MPY and QPEEK-MPRD demonstrated a loss in hydroxide conductivity of 28.5% and 33.4%, respectively. Both values were lower than that of QPEEK-TMA (37.7%). Therefore, among these side-chain-type QPEEKs membranes, QPEEK-MPY and QPEEK-MPRD, containing benzylmethylpyrrolidinium and benzylmethylpiperidinium as cation head-groups, are promising AEM materials for fuel cell construction.
基于侧链型季铵化聚醚醚酮（QPEEKs）制备了含有不同杂环脂族季铵基团的阴离子交换膜，该制备过程包括与含侧链甲基苯基的单体进行缩聚、溴甲基化，然后分别用1-甲基吡咯烷（MPY）、1-甲基哌啶（MPRD）、1-甲基咪唑（MIDZ）和N-甲基吗啉（MMPH）进行季铵化。然后将这些膜的性能与含有苄基三甲基铵的传统季铵化聚醚醚酮（QPEEK-TMA）的性能进行比较。合成了模型化合物QMPY、QMPRD、QMIDZ和QMMPH，并利用1H NMR定量比较了杂环脂族季铵基团的碱性稳定性。本研究结果表明，所有这些模型化合物的碱性稳定性顺序为QMPY＞QMPRD＞QTMA＞QMIDZ＞QMMPH。这些QPEEKs膜表现出优异的热稳定性、尺寸稳定性和机械稳定性。与QPEEK-MIDZ和QPEEK-MMPH相比，QPEEK-TMA、QPEEK-MPY和QPEEK-MPRD表现出更高的氢氧化物电导率和更低的活化能。此外，在60℃下于1 M NaOH中暴露24天后，QPEEK-MPY和QPEEK-MPRD的氢氧化物电导率分别下降了28.5%和33.4%。这两个值均低于QPEEK-TMA（37.7%）。因此，在这些侧链型QPEEKs膜中，含有苄基甲基吡咯烷鎓和苄基甲基哌啶鎓作为阳离子头基的QPEEK-MPY和QPEEK-MPRD是用于燃料电池构建的有前景的AEM材料。
