后磺化法精确可控合成主链型磺化聚苯喹喔啉及其质子交换膜性能研究  

Post-sulfonation for Precisely Controllable Preparation of Main-chain Type Sulfonated Poly (phenylquinoxaline)s and Their Properties for Proton Exchange Membrane

作　　者：刘璐 陈康成 Lu Liu;Kang-cheng Chen(School of Chemistry and Chemical Engineering,Beijing Institute of Technology,Beijing 102488)

机构地区：[1]北京理工大学化学与化工学院,北京102488

出　　处：《高分子学报》2020年第4期393-402,I0004,共11页Acta Polymerica Sinica

基　　金：国家自然科学基金青年基金(基金号21306010)资助项目.

摘　　要：以不同摩尔比的4,4′-双(4-(2-苯基乙二酮基)苯氧基联苯、4,4′-双(2-苯基乙二酮基)二苯醚与3,3′,4,4′-四氨基联苯共聚制备聚喹喔啉,经后磺化法得到一系列磺化度可控的磺化聚苯基喹喔啉(SPPQ).模型化合物确认,磺酸基团精确接入电子云密度较高的含醚键的联苯片段的2,2′-位上,证明通过单体分子结构设计与后磺化法结合,可使磺酸基团在温和条件下,按预想接入到聚合物主链上,达到磺化度和磺化位置精确可控的目的. SPPQ的相对黏度均在3.8 dL/g以上.通过溶液涂膜法制备的主链型磺化聚苯基喹喔啉质子交换膜(SPPQ PEM)的吸水率都低于39%,尺寸变化率为2.1%~13%,且随着IEC和温度的提高而线性增加.如,80℃下,IEC高达2.21 meq/g的SPPQ-5的膜面和膜厚方向的尺寸变化率仅为11%和13%,具有良好的形状维持能力.热重分析表明,SPPQ PEM在320℃左右脱去磺酸基团,550℃左右发生聚合物主链降解,具有良好的热稳定性. Fenton试剂测试表明,SPPQ PEM开始破碎的时间随IEC的增加而缩短,在20℃时,IEC较低的SPPQ-1 (1.29 meq/g)破碎时间可达151 h,而IEC较高的SPPQ-5(2.21 meq/g)破碎时间缩短至81 h. PEM的质子传导率随温度和IEC的增加而显著提高,最高可达64 mS/cm,由于磺酸基团和喹喔啉酸碱对的形成以及吸水率偏低的原因,这一数值远低于Nafion.A series of main-chain type sulfonated poly(phenylquinoxaline)(SPPQ) were prepared by postsulfonation of PPQs, which were synthesized from copolymerization of 4,4′-bis(4-(2-phenylethylenedione)phenoxybiphenyl and 4,4′-bis(2-phenylethylenedione)diphenylether with 3,3′, 4,4′-tetraaminobiphenyl under different molar ratios. They were confirmed by the model compounds that sulfonic acid groups were precisely introduced to the 2,2′-position of the biphenyl fragment with high electron cloud density on SPPQ backbone.Therefore, sulfonic acid groups can be predicablely introduced to the polymer main-chain under mild conditions by the combination of monomer molecular structure design and post-sulfonation proceeding. Relative viscosity of these SPPQs was higher than 3.8 dL/g, indicating their high molecular weight. SPPQ-based proton exchange membranes(PEMs) were prepared by solution casting method. Their properties such as ion exchange capacity(IEC), water uptake, swell ratio, oxidative stability, mechanical properties and proton conductivity were investigated. The TGA results indicated that SPPQ PEMs had good thermal stability with the desulfonic acid groups temperature at about 320 ℃ and the decompose temperature at about 550 ℃. All SPPQ PEMs showed water uptake less than 39% and in-plane swelling ratio linearly increased with increasing IEC and temperature,with the values ranging from 2.1% – 13%. For example, SPPQ-5 with the IEC value up to 2.21 meq/g showed excellent dimensional stability with only 11% and 13% in-plane direction and thickness direction of the swelling ratios at 80 ℃, respectively. Free radical oxidative stability test in Fenton reagent showed that the breaking time of SPPQ PEMs decreased with increasing IEC. For example, the SPPQ-1(1.29 meq/g) has breaking time of over 150 h at 20 ℃, whereas the value decreased to 81 h for SPPQ-5(2.21 meq/g). Proton conductivity of SPPQ PEMs were increased obviously with the increase of temperature and IEC, and the maximum proton conductivity reached

关 键 词：磺化聚苯基喹喔啉 质子交换膜 后磺化法 燃料电池 

分 类 号：TM911.4[电气工程—电力电子与电力传动] TB383.2[一般工业技术—材料科学与工程]