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全氟磺酸离子交换膜的制备

Processing of Perfluorosulfonated Ion-Exchanged Membranes

【作者】 王凤霞

【导师】 苑会林;

【作者基本信息】 北京化工大学 , 材料加工工程, 2007, 硕士

【摘要】 全氟磺酸酸离子交换膜(PFSIEM)是离子膜氯碱工业和质子交换膜燃料电池的核心材料,其工业化技术为挤出压延法,且仅为杜邦公司和日本Asahi等国外公司所掌握,国内用膜完全依赖进口。本工作研究了PFSIEM挤出加工技术:熔融挤出法和凝胶挤出法。所用树脂为东岳集团的全氟磺酸树脂(氟型:PFSR,氢型:PFSA)。利用DSC和TG对PFSR的热性能进行了分析,对PFSR的熔融指数和毛细管流变性能进行了测定,结果表明:PFSR热稳定性优异,在190℃下MI值为3.3g/10min,熔体属假塑性流体、有切力变稀的流动特性。PFSR适于熔融挤出法成型,通过在一定范围内调整挤出机挤出速度和三辊上光机的牵引速度可得到厚度不同、表观平整密实的薄膜。通过XRD分析了薄膜的结晶性,测定了PFSIEM的含水率、吸水率、溶解度、IEC值以及水化后膜的尺寸变化率,研究了工艺对PFSIEM力学性能的影响,结果表明:挤出PFSIEM具有良好的结晶度;膜的水合性、耐溶解性、IEC值受工艺影响不明显,纵向尺寸变化率小于横向;随着牵伸作用的增加,膜的横向最大拉伸强度无明显变化(17MPa),纵向逐渐增大(达22MPa);170℃下对膜热处理使拉伸强度有一定提高。以GBL作增塑剂熔融挤出得到增塑型薄膜,表观较未增塑薄膜下降,结晶度有所改善,拉伸强度、水化后尺寸变化率略有变化,增塑对薄膜的水合性、耐溶解性、IEC值没有影响。以GBL为潜溶剂配置PFSA凝胶体系,体系PH值为4,因此凝胶挤出法所用设备需具有很好的耐酸腐蚀性。凝胶法成型的薄膜的表观质量和结晶度较熔融挤出法的下降。

【Abstract】 Perfluorosulfonated ion-exchanged membrane (PFSIEM) is the core material for alkali-chloride industry and proton-exchanged membrane fuel cell (PEMFC). The manufacture technology of PFSIEMs is extrusion-calendering, which is mastered by Dupont and Asahi, therefore domestic need has being depending on importation. In this work, we researched extrusion processing technology of PFSIEMs, including melt-extrusion and gel-extrusion. Resin used is made in Dongyue Company, one is Perfluorosulfonyl fluoride resin(PFSR), the other is perfluorosulfonic acid resin(PFSA).DSC, TG, and capillarity rheometer were used to study the thermal stability and melt rheology of the PFSR. The results showed that PFSR has outstanding thermal stability, furthermore, the MI is 3.3g/10min at 190℃, and PFSR melt was a pseudoplastic fluid had a characteristic of shear thinning. So, PFSR is fit to melt-extrusion processing, and different thickness membranes with good appearance can be prepared by adjusting the extrusion speed and the linear speed of grazer.XRD were used to study the crystallinity of PFSIEMs, the results showed PFSIEMs have good crystallinity. Water content, water absorption, solubility, and IEC were tested, the results showed that these parameters were little affected by art of processing. Dimension change of PFSIEMs were tested, results showed that dimension change in machine direction (MD) were less than that in transverse direction (TD). The effect on mechanical property of PFSIEMs of processing art have been studied, results showed that along with the extension increasing the max. tensile strength didn’t change obviously in TD (17MPa) but increased gradually in MD(reached 22MPa). Moreover, the tension strength of PFSIEMs can be improved by hot treating at 170℃.The PFSIEMs plasticized by GBL got inferior surface, but crystallinity is improved. Tension strength and dimension change are slightly changed after plasticizing. IEC and hydration property did not affected by plasticization.Prepared PFSA gel system by using GBL as the latent solvent, and the PH of gel system reached 4. Thus, it is demand that all the machines and equipments used during gel-extrusion procedure with excellent acid resistance. Gel-extruded membranes have worse surface and crystallinity than melt-extruded ones.

  • 【分类号】TB383.2
  • 【被引频次】3
  • 【下载频次】835
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