Abstract: The alkaline anion-exchange membranes were developed from poly(vinyl alcohol)/quaterized hydroxyethylcellulose ethoxylate (PVA/QHECE) by incorporating polyethylene glycol (PEG) as a plasticizer using chemical and physical cross-linking method. The PVA/QHECE/PEG membranes were characterized in detail at structural and hydroxyl ion (OH^-) conducting property by AC-impedance spectroscopy, FTIR spectroscopy, scanning electron microscopy (SEM), thermal gravity analysis(TG), gas chromatogram (GC) and tensile strength technique. The results show that the membrane flexibility and mechanical property are highly improved by incorporating PEG, especially for the membranes with high content of QHECE. The thermal stability of the membranes with PEG (300℃) is 40℃ higher than that of without PEG (260℃). No decreaes in OH^- condutivity was observed for the membranes after conditioning in 80℃, 6 mol/L KOH for 264 h. On the contrary, the OH^- conductivity increased from 1.06×10^-3 S/cm (before conditioning) to 3.88×10^-3 S/cm(after conditioning), while no obvious change in water uptake was observed. In addition, the methanol permeability of the PVA/PAADDA/PEG membranes are all lower than 10^-7 cm²/s, which is only 1/20-1/40 of Nafion^®117 under the same measuring conditions, indicating that the membranes are promising for potential use in alkaline direct methanol fuel cells.

Key words: Alkaline anon-exchange membrane, Poly(vinyl alcohol), Quaterized hydroxyethylcellulose ethoxylate, Polyethyleneglycol, Chemical and physical cross-linking, Alkali resistance stability, Methanol permeability