基于季铵化壳聚糖-聚乙烯醇互穿网络型复合碱性聚电解质膜

Quaternized Chitosan-Polyvinyl Alcohol Based IPN Composite Alkaline Polymer Electrolyte Membranes

通过对溶胶-凝胶法所制的纳米SiO_2进行季铵化改性得到季铵化SiO_2(QSiO_2),再将其与季铵化壳聚糖(QCS)和聚乙烯醇(PVA)的共混膜基体进行复合,经戊二醛交联制备了一系列不同QSiO_2添加量的互穿网络型QCS-PVA/QSiO_2复合碱性聚电解质膜。采用红外光谱、扫描电镜、热重分析、交流阻抗等考察了膜的结构、热稳定性和OH-离子电导率等。结果表明,无机粒子的加入使得复合膜的热稳定性提高,离子电导率呈现先上升后下降的趋势,在QSiO_2质量分数为5%时,其室温离子电导率达到最高0.0644 S/cm,是未添加QSiO_2的纯膜电导率(0.022 S/cm)近3倍,有望作为碱性聚电解质膜用于燃料电池中。

Quaternized SiO_2（QSiO_2） was firstly prepared by modification of nano-sized SiO_2 using silane coupling agent with quaternary ammonium groups.And then,a series of quaternized chitosan-poly（vinyl alcohol）/QSiO_2（QCSPVA/QSiO_2） interpenetrating polymer networks（IPN） composite membranes were fabricated by adding QSiO_2 into the QCS-PVA blend matrix and followed by glutaraldehyde crosslinking.The structure,thermal stability and ionic conductivity of the composite membranes were characterized by FT-IR,SEM,thermogravimetric analysis（TG） and electrochemical impedance spectroscopy（EIS）.The results show that the thermal stability of the composite membranes is significantly improved.The ionic conductivity of QCS-PVA/QSiO_2 composite membranes exhibits a trend of rise first then fall.The QCS-PVA/QSiO_2 composite membranes with 5% QSiO_2 show the highest ionic conductivity as high as 0.0644 S/cm,which is about three times of the ionic conductivity of the pure QCS-PVA membrane（0.022 S/cm） at room temperature,indicating the potential application of these composite membranes in fuel cells.