Gemini型碱性离子液体的制备及其在吡啶功能化PVA阴离子膜中的应用  

Synthesis of Gemini Basic Ionic Liquids and Its Application for Anion Exchange Membranes Based on Pyridine Functionalized Poly(vinyl alcohol)

作　　者：王一夫[1] 万贺廷 王丹[1] 王吉林[1] 王璐璐[1] 封瑞江[1] Yi-fu Wang, He-ting Wan, Dan Wang, Ji-lin Wang, Lu-lu Wang, Rui-jiang Feng(School of Petroleum and Chemical Technology, College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun 11300)

机构地区：[1]辽宁石油化工大学化学化工与环境学部,抚顺113001

出　　处：《高分子学报》2018年第4期541-552,共12页Acta Polymerica Sinica

基　　金：辽宁省科技厅博士启动项目(项目号20141126);辽宁省教育厅科学研究一般项目(项目号L2013153);抚顺市科学技术发展资金计划项目(项目号20141115)资助

摘　　要：通过两步法合成具有Gemini结构的碱性十二烷基吗啉离子液体([Nbmd]OH).并将制得的离子液体引入吡啶功能化聚乙烯醇(PVA-FP)为基质的阴离子交换膜制备过程中,通过流延法制备PVAFP/[Nbmd]OH复合膜.借助傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、X射线衍射(XRD)、交流阻抗(AC)、热重分析(TGA)及机械性能测试等对复合膜的结构及理化性能进行表征.结果表明,该系列复合膜形貌平整均一,吡啶基团的引入增强了PVA基质膜的热稳定性及耐碱稳定性.[Nbmd]OH离子液体的引入,在提供更多阳离子活性点位的同时,降低了复合膜结晶度,提高了电导率,改善了机械性能.其中,当质量比m(PVA)∶m([Nbmd]OH)=1∶2.5时,复合膜的热分解温度较PVA膜提高75oC;70oC时电导率达到4.42×10^(-2)S?cm^(-1);在80oC,6 mol/L KOH溶液中进行加速老化实验,浸泡400 h后电导率为初始电导率的1.6倍左右,表现出优异的耐碱稳定性;在30oC,3 mol/L甲醇溶液中甲醇透过率仅为Nafion~?-117膜的2.5%~5%,表现出很好的阻醇性能.A new Gemini basic morpholine ionic liquid （IL, [Nbmd]OH） was synthesized with morphline, bromodecane and 1,4-dibromobutane via a two-step procedure. The structure of the new IL was characterized by 1H-NMR and FTIR. A series of anion exchange membranes （PVA-FP/[Nbmd]OH） were prepared by casting method with pyridine functionalized poly（vinyl alcohol） as the polymer matrix. The PVA-FP/[Nbmd]OH composite membranes were characterized in details by AC-impedance spectroscopy, Fourier transform infrared spectroscopy （FTIR）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, thermal gravimetric analysis （TGA） and tensile strength test. The results indicated that PVA-FP/[Nbmd]OH composite membranes have uniform morphology, and the introduction of pyridine groups enhance the thermal stability and alkali resistance of PVA matrix, due to the formation of the hyper conjugation structure between a bond （C--H bond in methyl group） and π-bond conjugated region （pyridine group）, therefore enlarging the conjugated region, decreasing the positive charge density of the cations. Meanwhile, [Nbmd]OH ionic liquid not only provided more cationic active sites but also reduced the crystalline of the composite membranes, resulting in an increase of OH- conductivity and an improvement of the mechanical properties. When the weight ratio of [Nbmd]OH to PVA was 2.5, the thermal decomposition temperature of the composite membrane was 75℃ higher than that of the pristine PVA membrane; the maximum OH- conductivity was found at about 4.42 × 10-2 S.cm-1 at 70℃; no obvious decrease in OH- conductivity was observed for the composite membrane after immersing in 6 mol/L KOH solution at 80℃. On the contrary, the OH- conductivity was improved to 1.6 times of the initial OH- conductivity after 400 h immersion time, showing an excellent alkali resistance stability. In addition, the methanol permeability of the composite membrane determined using 3 mol/L methanol solution at 30℃ was only about 2.5% - 5

关 键 词：阴离子交换膜 聚乙烯醇 离子液体 耐碱稳定性 甲醇透过率 

分 类 号：TQ425.236[化学工程]