Synthesis and characterization of poly(para-phenylene disulfonic acid), its copolymers and their n-alkylbenzene grafts as proton exchange membranes: high conductivity at low relative humidity
Synthesis and characterization of poly(para-phenylene disulfonic acid), its copolymers and their n-alkylbenzene grafts as proton exchange membranes: high conductivity at low relative humidity
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DOI：
10.1039/c2jm33066k
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发表时间：
2012-09
影响因子：
--
通讯作者：
Kun Si;Daxuan Dong;R. Wycisk;M. Litt
中科院分区：
文献类型：
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作者：
Kun Si;Daxuan Dong;R. Wycisk;M. Litt
采用乌尔曼偶联法将1，4-二溴苯-2，5-二磺酸和4，4 '-二溴联苯-3，3'-二磺酸锂盐直接聚合，然后在聚合物骨架上接枝长尾烷基苯基团，合成了水不溶性聚对苯二磺酸及其共聚物。离子交换容量为4.3至7.7毫当量的共聚物。g-1的值。采用核磁共振、热重分析、差示扫描量热法和粘度计对在优化条件下制备的聚合物和共聚物进行了表征。通过调节单体组成、改变接枝反应温度和时间来调整共聚物的物理化学特性。这些聚合物每个酸基可以容纳八个或更多的强结合水分子，这有助于它们的高导电性。在干燥状态下，聚合物非常脆。在高温和低相对湿度下，由这些聚合物制备的膜的质子电导率比Nafion® 212高出十倍。
Water insoluble poly(para-phenylene disulfonic acid) and its copolymers were synthesized by direct polymerization of 1,4-dibromobenzene-2,5-disulfonic acid and 4,4′-dibromobiphenyl-3,3′-disulfonic acid lithium salts using Ullmann coupling and subsequent grafting of long-tail alkylbenzene groups onto the polymer backbones. Copolymers with ion exchange capacities of 4.3 to 7.7 meq. g−1 were obtained. Polymers and copolymers prepared under optimized polymerization conditions were characterized by NMR, TGA, DSC and viscometry. The physicochemical characteristics of the copolymers were tailored by adjusting monomer compositions and by varying the grafting reaction temperature and time. These polymers could hold eight or more strongly bound water molecules per acid group, which facilitated their high conductivity. In the dry state, the polymers were very brittle. Membranes prepared from these polymers exhibited proton conductivity as much as ten times higher than that of Nafion® 212, at elevated temperature and low relative humidity.