具有疏水链桥结构的磺化聚酰亚胺质子交换膜材料的设计与构筑

The preparation and study of polymer proton exchange membranes is a key topic in the clean energy field, especially the proton exchange membrane fuel cell field. The polymer molecular structure and crosslinking structure has a significant effect on the macromolecular conformation and stacking as well as the physic properties of the polymer materials. The key point of the project is to realize the formation and controlling of hydrophilic/hydrophobic microphase-separated morphology in the highly sulfonated crosslinked polyimide proton exchange membrane through the regulation of the molecular structure and hydrophobic chain-bridge structure. In this project, the highly sulfonated crosslinked polyimide proton exchange membrane materials containing hydrophobic chain bridge structure will be prepared through a polycondensation from the diamine monomer containing cross-linkable tetrafluorostyrol side-groups, and thermal crosslinking reaction. We hope to investigate the influence of the molecular structure, crosslinking density, the degree of sulfonation and the density of hydrophobic chain bridge structure in per polymer repeat unit on the controlling of hydrophilic/hydrophobic microphase-separated morphology and performance for the highly sulfonated crosslinked polyimide proton exchange membranes. Finally, we hope to prepare the highly sulfonated crosslinked polyimide proton exchange membrane with high proton conductivity, low swelling ratio, and high stability. Moreover, we hope that the study of the project could lay the theoretical and experimental foundation for the design and preparation of high-performance polyimide proton exchange membrane materials.

聚合物质子交换膜的制备与研究一直是质子交换膜燃料电池乃至清洁能源领域的一个重点课题。聚合物材料的分子结构和交联结构对分子链构象及堆积进而对材料的物理性能有重要影响。本项目拟通过分子结构和疏水链桥结构的调控来实现高磺化度交联聚酰亚胺质子交换膜亲水-疏水微相分离形貌的形成与控制。设计合成含有可交联四氟苯乙烯侧基的二胺单体，经过缩聚反应及热交联处理制备具有疏水链桥结构的高磺化度交联聚酰亚胺质子交换膜材料。研究分子结构、交联密度、磺化度和聚合物分子重复单元内的疏水链桥结构密度对磺化聚酰亚胺膜亲水-疏水微相分离形貌控制和性能的影响，制备具有高质子传导率、低溶胀率、高稳定性的高磺化度交联聚酰亚胺质子交换膜材料，为高性能聚酰亚胺质子交换膜材料的设计和制备奠定理论和实验基础。

磺化聚酰亚胺因为具有优异的机械性能、突出的耐热、化学稳定性和低的燃料渗透性能，近年来作为聚合物质子交换膜获得了广泛研究。本项目针对高磺化度大幅降低磺化聚酰亚胺质子交换膜尺寸稳定性、抗燃料渗透性能、机械性能及耐水性的缺点，提出主链结构和网络结构工程相结合的策略制备高性能交联型高磺化度聚酰亚胺质子交换膜。首先设计合成了四种具有不同分子结构和不同数量四氟苯乙烯侧基的二胺单体，并利用这四种单体分别与磺化二胺单体及萘四甲酸二酐通过共聚合成了可交联的高磺化度聚酰亚胺。利用流延铸膜、交联及酸化处理制备了多个系列高磺化度交联型聚酰亚胺质子交换膜。通过改变构筑单体分子结构和尺寸实现了交联型磺化聚合物电解质亲水-疏水微相分离形貌的调控，高效离子传输通道的构建和质子传导率显著提高，同时依靠疏水交联结构的引入及交联密度、磺化度、聚合物分子重复单元内的疏水链桥结构密度的控制实现了尺寸稳定性、抗氧化稳定性、阻醇性能等性能的同步优化。制备的交联型高磺化度聚酰亚胺膜作为膜电极组装的直接甲醇燃料电池呈现了优异的性能和高功率密度，表明其作为直接甲醇燃料电池质子交换膜材料的潜在应用前景。我们在高性能交联型磺化聚酰亚胺质子交换膜的设计制备、性能表征等方面积累了丰富经验，初步完善了性能改进的策略和建立了磺化质子交换膜的结构与性能之间的关系。在项目执行期内发表有该基金编号的SCI 论文17篇，申请发明专利2项。培养硕士研究生3名，博士研究生3名。