Anion exchange membrane from polyvinyl alcohol functionalized with quaternary ammonium groups via alkyl spacers

Anion exchange membranes (AEMs) functionalized with quaternary ammonium groups are prepared from polyvinyl alcohol for alkaline polymer electrolyte fuel cell (APEFC) application. A series of AEMs were synthesized by direct quaternization of PVA using flexible alkyl spacer as charge carrier added in different weight percentages. These membranes were further cross-linked chemically and thermally before evaluating their ionic conductivity and ion exchange capacity. The interaction of alkyl spacer group with the polymer backbone was confirmed by FT-IR spectroscopy. XRD pattern reveals that the introduction of quaternary ammonium group disrupts the crystalline structure of polymer, increasing its amorphous phase thereby enhancing the conductivity. The QPVA membrane with 15 wt% of alkyl spacer exhibited an improved conductivity of 0.0057 S cm(-1) at 40 A degrees C in comparison with other ratios. The cell polarization data for the optimized QPVA membrane was studied at 40 A degrees C with varying ionomer amount. The alkaline stability and cell durability for the optimized QPVA membrane were evaluated for 300 and 25 h, respectively.