PGA纳米纤维改性磺化聚醚砜质子交换膜的制备与性能研究

发布时间：2018-03-18 12:00

  本文选题：聚谷氨酸　切入点：纳米纤维　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：质子交换膜燃料电池(PEMFC)是一种可以将化学能直接转换成电能的装置,其具有功率密度高、能源利用率高、环保、启动快等优点,是能源利用的一种新方式。质子交换膜(PEM)是其核心部件之一,起到传递质子和隔绝燃料的作用,其性能的优劣直接决定电池的性能。目前商业化的全氟磺酸膜具有昂贵的成本、高温低湿时较低的质子传导率、较高的甲醇渗透率等缺陷,严重阻碍了质子交换膜燃料电池的广泛应用。因此高性能、高性价比质子交换膜的开发成为当前研究热点。近年来,具有大比表面积、较高长径比、较好机械性能的纳米纤维,被许多科研工作者应用到质子交换膜中以提高质子交换膜的机械性能和质子传导性能。本论文以磺化聚醚砜为基础,通过引入聚谷氨酸纳米纤维来构建质子传输通道的方式制备高性能的质子交换膜。主要研究内容如下:通过溶液喷射纺丝技术制备不同PGA含量的纳米纤维,分析了牵伸风速和聚谷氨酸的含量对纤维成型的影响。通过FESEM测试、FTIR分析、XPS分析和TGA分析表明随着牵伸风速的增加纳米纤维的成型性逐渐增加,当牵伸风速过大时纤维缠结严重;随着PGA含量的增大纤维表面疵点增多,纤维直径增大,热稳定性增加。通过电化学测试表明PGA纳米纤维随着温度和湿度的升高纳米纤维的电导率逐渐增大,另外随着PGA含量的增加,纤维电导率也逐渐增加。通过溶液浸渍的方法制备了不同聚谷氨酸纳米纤维含量的SPES复合膜,复合膜的表面平整致密,纳米纤维被SPES基质完全包覆两者相容性好。TG测试结果显示,纳米纤维的加入复合膜具有足够的热稳定性适用于直接甲醇燃料电池质子交换膜。聚谷氨酸纳米纤维复合膜的吸水率随纤维含量的增大而增加,相比于SPES膜,复合膜的吸水率得到了极大的改善,复合膜的溶胀率在合理范围内。通过引入纳米纤维成功构建了质子传输通道,并改善了 SPES膜的质子传导率,且复合膜的质子传导率随着纳米纤维含量的增加呈增加趋势。SPES-30复合质子交换膜的质子传导率最好,在80℃时高达0.261 Scm~(-1)。所有复合膜的阻醇性能均优于纯SPES膜,并且随着聚谷氨酸纳米纤维的增加甲醇渗透系数减小。同时SPES-30具有最好的选择性其值为29.72×104sscm-3。利用辅助电极法静电纺丝技术成功制备取向PGA纳米纤维,通过溶液浸渍的方法,将纳米纤维与SPES形成了复合质子交换膜。通过扫描电镜、XPS、XRD以及TG测试表明取向PGA纳米纤维成功制备,并且具有较好的取向性和热稳定性;通过电化学性能测试表明所制备的取向PGA纳米纤维复合膜具有较好的质子传到导性能,在复合膜的取向方向上质子电导率在100%湿度和80℃时为0.368 Scm~-1。
[Abstract]:Proton exchange membrane fuel cell (PEMFC) is a device that can convert chemical energy directly into electric energy. It has the advantages of high power density, high energy efficiency, environmental protection, fast start-up and so on. PEM is one of the core components of PEM, which plays the role of proton transfer and fuel isolation. The performance of PEM directly determines the performance of the battery. At present, the commercial perfluorosulfonic acid membrane has high cost. Low proton conductivity and high methanol permeability at high temperature and low humidity seriously hinder the wide application of proton exchange membrane fuel cells. Therefore, the development of proton exchange membrane with high performance and high performance-to-price ratio has become a research hotspot in recent years. Nanofibers with large surface area, high aspect ratio and good mechanical properties have been applied to proton exchange membranes to improve the mechanical properties and proton conductivity of proton exchange membranes. This paper is based on sulfonated polyether sulfone (sulfonated polyether sulfone). High performance proton exchange membranes were prepared by introducing poly (glutamic acid) nanofibers to construct proton transport channels. The main research contents are as follows: different PGA nanofibers were prepared by solution jet spinning. The effects of draft velocity and content of poly (glutamic acid) on fiber molding were analyzed. The results of FESEM, FTIR and TGA analysis showed that the formability of nanofibers increased with the increase of draft velocity. With the increase of PGA content, fiber surface defects increase and fiber diameter increases. The electrical conductivity of PGA nanofibers increases with the increase of temperature and humidity, and the electrical conductivity increases with the increase of PGA content. The SPES composite films with different content of polyglutamic acid nanofibers were prepared by solution impregnation, and the surface of the composite films was smooth and compact. The nanofibers were completely coated with SPES matrix with good compatibility. TG test showed that, The thermal stability of nanofiber composite membrane is suitable for direct methanol fuel cell proton exchange membrane. The water absorption of polyglutamic acid nanofiber composite membrane increases with the increase of fiber content, compared with that of SPES membrane. The water absorption of the composite membrane was greatly improved and the swelling rate of the composite membrane was within a reasonable range. The proton transport channel was successfully constructed by introducing nanofibers and the proton conductivity of the SPES membrane was improved. The proton conductivity of the composite membrane increased with the increase of nano-fiber content. The proton conductivity of SPES-30 composite proton exchange membrane was the best, and reached 0.261 Scm-1 ~ (-1) at 80 鈩，

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