Imidazolium-functionalized polysulfone hydroxide exchange membranes for potential applications in alkaline membrane direct alcohol fuel cells

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• 作者：Xiaoming Yan^a ; Gaohong He^a ; ^{hgaohong@dlut.edu.cn} ; Shuang Gu^b ; Xuemei Wu^a ; Liguang Du^a ; Yongdong Wang^a
• 关键词：Polysulfone ; Imidazolium ; Menshutkin reaction ; Hydroxide exchange membrane ; Alkaline membrane direct alcohol fuel cell
• 刊名：International Journal of Hydrogen Energy
• 出版年：2012
• 期刊代码：42_03603199
• 类别：ch
• 出版时间：March, 2012
• 卷：37
• 期：6
• 页码：5216-5224
• 文件大小：768 K

摘要

A series of imidazolium-functionalized polysulfones were successfully synthesized by chloromethylation-Menshutkin two-step method. PSf-ImOHs show the desired selective solubility: insoluble in alcohols (e.g., methanol and ethanol), and soluble in 50聽vol.%aqueous solutions of acetone or tetrahydrofuran, implying their potential applications for both the alcohol-resistant membranes themselves and the ionomer solutions in low-boiling-point water-soluble solvents. PSf-ImOH also possesses very high thermal stability (T_OD: 258聽掳C), higher than quaternary ammonium and quaternary phosphonium functionalized polysulfones (T_OD: 120聽掳C and 186聽掳C, repsectively). Ion exchange capacity (IEC) of PSf-ImOH membranes ranges from 0.78 to 2.19聽mmol聽g^鈭? with degree of chloromethylation from 42%to 132%of original chloromethylated polysulfone. As expected, water uptake, swelling ratio, and hydroxide conductivity increase with IEC and temperatures. With 2.19聽mmol聽g^鈭? of IEC, the PSf-ImOH 132%membrane exhibits the highest hydroxide conductivity (53聽mS聽cm^鈭? at 20聽掳C), higher than those of all other reported polysulfone-based HEMs (1.6-45聽mS聽cm^鈭?) and other imidazolium-functionalized HEMs (19.6-38.8聽mS聽cm^鈭?). In addition, PSf-ImOH membranes have low methanol permeability of 0.8-4.7聽脳聽10^鈭?聽cm²聽s^鈭?, one order of magnitude smaller than that of Nafion212 membrane. All these properties indicate imidazolium-functionalized polysulfone is very promising for potential applications in alkaline membrane direct alcohol fuel cells.