Influences of Annealing on the Perfluorosulfonate Ion-Exchanged Membranes Prepared by Melt Extrusion

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• 作者：Jing Wang ; Miaokun Yang ; Peng Dou ; Xuejun Wang ; Heng Zhang
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：September 10, 2014
• 年：2014
• 卷：53
• 期：36
• 页码：14175-14182
• 全文大小：392K
• ISSN：1520-5045

文摘

Perfluorosulfonate ion-exchanged membranes (PFSIEMs) have been prepared by the melt-extrusion method. Subsequently, the effect of annealing on the properties of PFSIEMs was studied. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) analysis suggested that 鈭扴O₃^{鈥?/sup> groups could be brought to the membrane surface, presumably by side chain movement during the course of thermal annealing. In the presence of coexisting ion clusters and crystallization, area resistance increased with the rise of the treatment temperature. X-ray diffraction (XRD) analysis further showed that the annealing treatment should increase the crystallinity of membranes, markedly. The equivalent weight (EW) and water uptake were also employed to evaluate the effect of annealing on membranes. For membranes prepared by melt extrusion, abnormal fluctuations are solely evident in the thermogravimetric (TG) traces of annealed specimens. In addition, two glass transition temperatures, ca. 120 and ca. 250 掳C, have been observed in the differential scanning calorimetry (DSC) analysis. When the thermal annealing temperature was increased, however, the lower endothermic peak shifted to the high temperature region, mostly because water molecules can serve as the plasticizer to reduce T_g. In addition, we also found that the dynamic mechanical property of membranes can be substantially impacted by annealing. Changes in the temperature relaxation have been explored with dynamic mechanical analysis (DMA).}