三甲胺聚砜氢氧根离子交换膜的均相法制备与性能

Homogeneous Trimethylamine Quaternization and Properties of Polysulfone Hydroxide Exchange Membrane

以氯甲基化聚砜为基材,三甲胺为季铵化试剂,开发均相溶剂完成均相季铵化反应,解决三甲胺非均相季铵化存在的反应不均匀、碱性功能基团不易聚集成簇等影响电性能提高的问题。实验结果表明,均相季铵化法制备聚砜氢氧根离子交换膜（Homo PSF-Qa OH）的离子交换容量（IEC）为0.56-1.28 mmol/g,比相同氯甲基化程度的非均相季铵化聚砜氢氧根离子交换膜（Heter PSF-Qa OH）提高约10%,膜的含水量也相应提高约8.8%。然而,相同IEC下均相法制膜的氢氧根传导率提高程度远大于IEC和含水量的提高程度,提高约30%-40%。透射电镜照片表明均相法制膜季铵基团更容易聚集成簇,从而能够改善膜的微观相分离结构,促进氢氧根离子的传导。热重分析测试表明,2种膜的初始热分解温度（TOD）相当,达到159℃,远高于燃料电池的操作温度。

Homogeneous trimethylamine quaternization of polysulfone was successfully performed by using DMAc / aqueous trimethylamine mixed solvent. Properties,such as hydroxide conductivity,ion exchange capacity（ IEC）,water uptake,swelling ratios and thermal stability were characterized for both homogeneous and heterogeneous trimethylamine quaternized membranes. Experimental data shows that IEC of heterogeneous and homogeneous membranes is ranging from 0. 52 to 1. 13 mmol / g and 0. 56 to 1. 28 mmol / g respectively. IEC and quaternized degree（ DQ） of the homogeneous PSF-Qa OH membranes are improved,that is,the IEC increases by about 10%,and the water uptake increases by about 8. 8%. What is more,the increase of ion conductivity is much greater than that of the IEC and water uptake. For example,when IECmis 1. 0 mmol / g,the homogeneous membrane exhibits conductivity of 18 m S / cm（ 20 ℃） and 34.8 m S / cm（ 60 ℃）,which increase by about 29. 5% and 40. 3%,respectively,as compared with that of the heterogeneous membrane（ 13. 9 m S / cm（ 20 ℃） and 24. 8 m S / cm（ 60 ℃））. Furthermore,the onset decomposition temperature TODof two kinds of membranes reaches 159 ℃,which is much higher than typical operating temperature of fuel cell.