交联反应过程中生成咪唑杂环构建新的无水质子传输通道及传导机理研究

The usually commercial proton exchange membranes based on Nafion? and sulfonated aromatic polymers membranes at high ion exchange capacity are limited for practical applications in fuel cells at medium-high temperture operation,because of poor mechanical performance and low proton conductivity at high temperature. In this project，the sulfonated poly (arylene ether)s with reactive functional group were synthesized by polycondensation. The imidazole heterocycle was formed in cross-linking network through amidation action between carboxyl and amido processed covalent cross-linking reaction. On the one hand，covalent cross-linking improved the mechanical performance and chemical stabilty of PEM. On the other hand, imidazole heterocycle rings possess both donor and acceptor at hydrogen bonding sites,which are benefit to form selective proton transport channel to transport proton and to obstruct methanol.In combination of covalent crosslinking and imidazole heterocycle effect,it will provide a strategy to resolve the contradictions of the methanol permeability and proton conductivity, improve the proton conductivity and mechanical performance of PEM under low humidity.Furthermore,the project will investigate the preparation methods of novel sulfonated poly(arylene ether)s with imidazole heterocycle in cross-linking network and the comprehensive properties,compare the influence of covalent cross-linking and imidazole heterocycle rings on membrane performance,clarify the proton conducting mechanism based on imidazole heterocycle,Therefore,this project will favor to prepare excellent membranes and provide evidence for sulfonated poly(arylene ether)s with imidazole heterocycle application and development in PEMFCs.

目前商业上被广泛应用的Nafion?膜和被普遍研究的磺化芳香族聚合物膜在高温下尺寸稳定性较差、质子传导率较低，难以满足质子交换膜燃料电池在中高温操作时的要求。本申请课题拟从分子设计角度出发，通过缩聚反应合成出分别带有反应性官能团（羧基和二胺基）的磺化聚芳醚共聚物，铺膜后利用羧基与胺基的酰胺化作用形成共价交联，交联后在交联网络内形成咪唑杂环。通过共价交联提高膜的尺寸稳定性和化学稳定性，咪唑杂环充当质子的给体与受体，构建低相对湿度下的质子传输通道。通过共价交联和咪唑杂环的协同作用，解决质子交换膜在高温时尺寸稳定性差和质子传导率低的问题。研究这种在交联网络中生成咪唑杂环的制备方法，共价交联和咪唑杂环对膜性能的影响，揭示咪唑杂环的质子传输机理，为咪唑杂环在质子交换膜中的应用和开发新型中高温用质子交换膜材料提供理论依据。

针对商用Nafion膜和被广泛研究的磺化聚芳醚酮砜膜在中高温下质子传导率较低的问题，该项目通过分子设计的方式，利用缩聚反应和酰胺化反应，制得了交联膜内含有咪唑杂环的磺化聚芳醚酮砜膜，该膜在120°C下，质子传导率达到0.08 S/cm.主要研究结果包括以下几个方面：（1）分别合成出了带有羧基的磺化聚芳醚共聚物和带有二胺基的磺化聚芳醚共聚物，通过羧基与二胺基的两步酰胺化反应，制得了在磺化聚芳醚酮砜交联网络膜内具有咪唑杂环的中高温用质子交换膜。（2）制备出了含有不同羧基含量的磺化聚芳醚酮砜聚合物，再通过羧基与氨基之间的酰胺化反应将3-氨基-1,2,4,三唑引入到聚合物链中，制备出了含有不同三唑含量的磺化聚芳醚酮砜质子交换膜（SPT-y）。（3）制备出了带有脂肪族磺酸的磺化单体，利用其与二氟二苯酮、双酚A共聚，制备出了含磺化烷基的不同磺化度的侧链型聚磺化芳醚酮质子交换膜。（4）利用带有羧基的磺化聚芳醚共聚物或带有氨基的磺化聚芳醚共聚物与磷钨酸、聚偏氟乙烯、氧化石墨烯等复合，制得了系列有机/无机杂化膜。. 在项目执行期内发表有该基金项目编号标注的SCI论文16篇，授权发明专利4项，作为第三完成人参加的成果“磺化聚芳醚类质子交换膜的结构构筑及传导特性调控”在2014年获得了吉林省科技进步（自然科学类）二等奖；作为第三完成人参加的成果“燃料电池用磺化聚芳醚类质子交换膜的分子设计与传输特性”获得了2014年吉林省自然科学学术成果二等奖。