采用化学法-萘钠溶液对疏水增强聚四氟乙烯(ePTFE)基底改性, 往基底孔中填充磺化聚苯并咪唑(SPBI)电解质, 通过多次真空抽滤和热处理法制备SPBI/ePTFE-x质子交换复合膜。分别采用红外光谱、扫描电镜、酸碱滴定法、干湿称重法和交流阻抗法等手段考察不同厚度的ePTFE基底对质子交换复合膜微观结构和性能的影响。结果表明:SPBI电解质成功填充于ePTFE基底中, 膜表面光滑且致密。基底越厚可填充的SPBI越多, 复合膜的IEC随基底ePTFE的厚度增加而增大, 吸水率也随之增大。SPBI/ePTFE-5复合膜水平和厚度方向的溶胀度为5.26%和2.41%, 说明具有较好的尺寸稳定性。SPBI/ePTFE-5复合膜基底厚度薄, 传输质子的路径短, 有利于质子间的传递, 获得了最佳的质子电导率, 在160℃时达到0.18S/cm, 表明SPBI/ePTFE-5质子交换复合膜在高温下具有良好的质子传导性能。
The hydrophobic enhanced polytetrafluoroethylene (ePTFE) substrate was modified by chemical method-sodium naphthalene solution.The SPBI/ePTFE-x proton exchange composite membrane was prepared through multiple vacuum filtration and thermal treatment by filling the substrate pores with sulfonated polybenzimidazole (SPBI) electrolyte.The effects of different thicknesses of ePTFE substrates on the microstructure and performances of the proton exchange composite membranes were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, acid-base titration, wet and dry weighing method and AC impedance method, respectively.The experimental results showed that the SPBI electrolyte had been successfully filled in the ePTFE substrate and the surface structure of the membrane was dense and smooth.The thicker the substrate, the more SPBI could be filled, and the IEC of the composite membrane increased with the increase of thickness of the ePTFE substrate, along with an increase in water uptake.The swelling ratios of SPBI/ePTFE-5 composite membrane in horizontal and thickness directions were 5.26% and 2.41%, respectively, indicating good dimensional stability.The SPBI/ePTFE-5 composite membrane had a thin substrate and a short path for proton transport, which facilitated the interproton transfer.SPBI/ePTFE-5 achieved the best proton conductivity, reaching 0.18S/cm at 160℃, demonstrating that the SPBI/ePTFE-5 proton exchange composite membrane had good proton conductivity at high temperatures.
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基金资助
国家自然科学基金(21306012);江苏省精细石油化工重点实验室开放课题基金资助项目(KF2106);江苏省研究生科研与实践创新计划项目(KYCX21-2857)
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