复合型聚芳醚类质子交换膜的制备与性能研究

发布时间：2018-05-22 09:03

本文选题：磺化聚芳醚酮砜 + 磷钨酸-离子液体　；参考：《长春工业大学》2017年硕士论文

【摘要】：质子交换膜燃料电池(PEMFCs)作为一种清洁能源,有望应用在便携式储能和供电站中,因此,得到了人们广泛的关注。和传统的发电装置相比,质子交换膜燃料电池工作时不需要燃烧化石燃料,而且污染物零排放。聚合物电解质膜(PEM)作为质子交换膜燃料电池的核心组成部分,其主要功能是将质子从阳极运输到阴极。现在,商业可用的质子交换膜(例如Nafion)仍然面临一些问题,比如成本高,燃料渗透,在高温下失水导致质子传导率明显下降等。因此,本论文针对上述问题,制备两种新型复合膜并开展研究工作。磺化聚芳醚类质子交换膜与现在商业化的Nafion膜相比,在很多方面都表现出更优良的性质,例如,更好的热稳定性和机械性能,相近的质子传导率,更低的燃料渗透率,最为重要的是成本低廉。在本文中,制备了基于磺化聚芳醚酮砜(SPAEKS)的有机-无机复合质子交换膜。首先制备了磷钨酸-离子液体填料(PWA-IL)。在PWA-IL中,通过磷钨酸和离子液体中咪唑环离子相互作用,使他们紧密结合,然后将PWA-IL掺杂到SPAEKS中,不仅可以提高质子传导率,而且由于氢键的作用,减少了离子液体的流失。测试结果表明,PWA-IL的引入使质子传导率得到了明显提高。尤为突出的是,将SPAEKS-80/PWA-IL膜浸泡在水中132 h后,PWA-IL保留能力达到了98.4%,膜材料的稳定性显著提高,同时也提高了阻醇性能。SPAEKS-80/PWA-IL复合膜在80 oC时,质子传导率达到0.127 S cm-1。通过上述研究,我们发现将PWA-IL引入到聚合物中有利于促进质子传导,其中起到主要作用的是咪唑环。咪唑环作为碱性官能团,容易和酸性官能团形成酸碱对,在酸碱对中,质子可以直接从质子给体(酸基)跳跃到质子受体(碱基)。这时质子在一定程度上依赖Grotthuss机理进行传输。进而,我们制备了不同种氮杂环修饰的聚芳醚酮聚合物质子交换材料,并研究其高温传导性能。聚合物主链是四甲基型聚芳醚酮(PAEK),通过NBS作为溴代试剂的溴代反应后,得到一定溴化度的溴代聚芳醚酮(BrPAEK)。利用活性溴甲基和氮杂环之间的相互作用,分别将吡啶(Pd),1-甲基咪唑(MeIm),苯三唑(BTA)和3-氨基-1,2,4-三唑(Am Tr)引入到聚合物。所得到的四种膜材料磷酸吸附能力有所不同,实验结果表明,引入甲基咪唑的膜能够吸收相对较多的磷酸,同时表现出最高的质子传导率。在170oC无水条件下,BrPAEK-MeIm1.6的质子传导率达到了0.091 S cm-1,同时热稳定性,氧化稳定性和力学性能都较为优异。
[Abstract]:Proton exchange membrane fuel cell (PEMFCs), as a clean energy source, is expected to be used in portable energy storage and power supply stations. Compared with conventional power generation devices, proton exchange membrane fuel cells do not need to burn fossil fuels and zero emission of pollutants. Polymer electrolyte membrane (PEM) is the core component of proton exchange membrane fuel cell (PEM). Its main function is to transport proton from anode to cathode. At present, commercially available proton exchange membranes (such as Nafion) still face some problems, such as high cost, fuel penetration, loss of water at high temperatures, and a significant decrease in proton conductivity. Therefore, in order to solve the above problems, two new composite membranes were prepared and studied in this paper. Sulfonated poly (aryl ether) proton exchange membranes exhibit better properties than commercial Nafion membranes in many ways, such as better thermal stability and mechanical properties, similar proton conductivity, lower fuel permeability, The most important thing is low cost. In this paper, an organic / inorganic composite proton exchange membrane based on sulfonated polyaryl ether ketone sulfone (SPAEKS) was prepared. Firstly, PWA-ILN was prepared with phosphotungstic acid-ionic liquid filler. In PWA-IL, phosphotungstic acid interacts with imidazole ring ions in ionic liquids to bind them tightly, and then doping PWA-IL into SPAEKS can not only increase proton conductivity, but also reduce the loss of ionic liquids due to the action of hydrogen bonds. The results show that the proton conductivity is improved by the introduction of PWA-IL. In particular, the retention ability of PWA-IL was 98.4 after immersion of SPAEKS-80/PWA-IL membrane in water for 132h, and the stability of the membrane material was improved significantly. At 80oC, the proton conductivity of SPAEKS-80 / PWA-IL composite membrane was increased to 0.127 Scm-1. It is found that the introduction of PWA-IL into the polymer can promote proton conduction, in which imidazole ring plays an important role. As basic functional group, imidazole ring can easily form acid-base pair with acidic functional group. In acid-base pair, proton can jump directly from proton donor (acid group) to proton receptor (base group). At this point, proton transport depends to some extent on the Grotthuss mechanism. Furthermore, different kinds of polyaryl ether ketone polymer proton exchange materials modified by nitrogen heterocyclic were prepared and their high temperature conductivity was studied. The main chain of the polymer is tetramethyl polyaryl ether ketone (PAEK). After bromination reaction with NBS as brominating reagent, brominated polyaryl ether ketone with certain bromination degree can be obtained. Based on the interaction between active bromomethyl and nitrogen heterocyclic, pyridine-1-methyl imidazolium (MeIman), triazolium (BTAA) and 3-amino-1-triazole-4-triazolium (Am) were introduced into the polymer, respectively. The adsorption capacity of phosphoric acid in the four kinds of membrane materials is different. The experimental results show that the membranes with methyl imidazole can absorb relatively more phosphoric acid and exhibit the highest proton conductivity. The proton conductivity of BrPAEK-MeIm1.6 was 0.091 Scm-1 under the condition of 170oC anhydrous, and the thermal stability, oxidation stability and mechanical properties of BrPAEK-MeIm1.6 were excellent.
【学位授予单位】：长春工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ425.236

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