侧链结构对磺化聚芳醚性能及微观形貌的影响

Effect of Side Chain Structure on Properties of Side Chain-style Sulfonated Poly(arylene ether)

比较了3种主链结构相同而侧链结构不同的磺化聚芳醚(SPAE)材料的性能.分析了侧链结构对聚合物的吸水、溶胀及质子传导行为的影响.结果表明,在相同的离子交换容量(IEC)条件下,具有柔顺脂肪族侧链的聚芳醚材料具有较高的质子传导率.其原因是由于柔顺的脂肪族侧链比刚性的芳香族侧链更易运动,有利于侧链末端磺酸基团的聚集,进而形成离子簇.3种聚合物微观形貌的分析结果表明,含柔顺侧链结构的聚合物薄膜具有更大的质子传输通道,其结果与聚合物的宏观吸水和传导现象相吻合.

Three kinds of sulfonated poly（arylene ether）（SPAE） with the same backbone and different side chains were prepared from the new difluoride monomer and other commercial monomers by nucleophilic substi-tution reaction. The relationship between structures and properties of these polymers were investigated. As a result, sulfonated polymers with flexibility aliphatic side chains exhibited high proton conductivity and low swelling ratio than that with aromatic ones at the same IEC level. Because the sulfonic acid groups located at the end of aliphatic side chain have better motility than located aromatic ones, which helps for aggregation of sulfonic acid and forming ionic clusters in the membranes. The microphase-separation morphology of the three polymers were analized by SAXS, The results indicate that polymers with more flexible side chains（SPAE-Ⅲ） have large phase separation size. Combined proton conductivity and water swelling data, SPAE-Ⅲ membranes are the most suitable one for proton exchange membrane application.