燃料电池用聚砜/聚乙烯醇复合阴离子交换膜的制备及性能研究

Preparation and Properties of Polysulfone/Poly(vinyl alcohol) Composite Anion Exchange Membrane for Fuel Cells

在制备氯甲基化聚砜(CPSF)的基础上,CPSF与4-(咪唑-1基)苯甲醛反应制备得到侧链含有醛基的季铵化聚砜(PSF-BA),接着PSF-BA与聚乙烯醇(PVA)通过化学反应制备一种交联型聚砜/聚乙烯醇聚砜阴离子交换膜(PSF-VA),在用红外光谱(FT-IR)表征其化学结构的基础上,重点研究了阴离子交换膜的吸水率(water uptaking,WU)、尺寸稳定性和耐碱性等性能。本文的PSF-VA复合阴离子交换膜在高吸水率下仍能保持很好的尺寸稳定性、耐碱性和机械性能,其中PSF-VA-3膜的离子交换容量(IEC)高达1.47 mmol/g,PSF-AC-3膜在25和85℃的吸水率(WU)达到了29.9%和47.6%,相应的氢氧根离子传导率为0.041和0.090 S/cm,但是溶胀率(SR)仅为13.7%和36.8%。在强碱中浸泡30天的氢氧根离子传导率保留量达到了84.7%,高传导率下保持很好的尺寸稳定性和耐碱性,克服了阴离子交换膜(AEM)在高离子传导率下尺寸稳定性和耐碱性差的问题。

A kind of quaternary ammonium polysulfone(PSF-BA) containing an aldehyde group on the side chain was obtained by the reaction of CPSF and 4-(imidazole-1-yl) benzaldehyde based on the preparation of chloromethylated polysulfone(CPSF). Subsequently, cross-linked polysulfone/poly(vinyl alcohol) anion exchange membrane(PSF-VA) was fabricated by the reaction of PSF-BA with polyvinyl alcohol(PVA). The chemical structure of modified polymer was characterized by infrared spectroscopy(FT-IR), and water uptaking(WU), size stability and alkali resistance were explored. PSF-VA composite AEMs keep excellent dimensional stability, alkali resistance and mechanical properties under high water absorption. The water absorption of PSF-AC-3 AEM(IEC is 1.47 mmol/g) at 25 and 85 ℃ is 29.9% and 47.6%, the hydrogen ion conductivity is 0.041 and 0.090 S/cm, but the swelling ratio is only 13.7% and 36.8%. The properties are even better than those of Nafion115 membrane under the same conditions. The PSF-AC AEM keeps good dimensional stability and alkali resistance at high conductivity, and the retention of ion conductivity is up to 84.7% after being soaked in strong alkali for 30 days, overcoming the problems of poor dimensional stability and alkali resistance of AEM under high ionic conductivity.