Synthesis and characterization of novel cross-linked quaternized poly(vinyl alcohol) membranes based on morpholine for anion exchange membranes

• Synthesis of a mild and nontoxic quaternization agent
• Introduce the ionic conductive groups by one step instead of traditional two steps
• Innovatively conducting the cross-linking reaction with bisphenol-A epoxy resin
• Relative excellent electrical and thermal properties

A series of novel cross-linked and quaternized poly(vinyl alcohol) (QPVA) anion exchange membranes were prepared for application in alkaline anion exchange membrane fuel cells. These membranes, with excellent electrical and thermal properties, were prepared via a relatively simple procedure, by using nontoxic and mild 4-methyl-4-glycidylmorpholin-4-ium chloride (MGMC), made in the laboratory, as a quaternization reagent to graft aliphatic morpholine ring units that acted as the fixed charged groups, followed by reacting the remaining unreacted hydroxyl groups with different amounts of bisphenol-A epoxy resin (DGEBA) and alkalization. The reaction products were characterized by nuclear magnetic resonance (1HNMR), Fourier transform infrared (FTIR), elemental analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and electrochemical methods. The membranes exhibited good thermal stability below 210 °C. The ionic conductivity can be as high as 5.21 × 10− 2 S·cm− 1 at 60 °C in water.