Synthesis and Properties of Chemically Cross-Linked Poly(<i>Vinyl Alcohol</i>)/quaterized Hydroxyethylcellulose Ethoxylate (<i>PVA/QHECE</i>) as Novel Alkaline Anion-Exchange Membrane

Abstract

A new type of chemically cross-linked polymer blend membranes consisting of poly(vinyl alcohol) (PVA) and quaterized hydroxyethylcellulose ethoxylate (QHECE) have been prepared and evaluated as OH--conducting polymer electrolytes. The OH--conductivity (s) of the membranes was investigated as a function of cross-linking time, blending composition and water uptake. Membrane swelling decreased with cross-linking time, accompanied by an improvement in mechanical properties and a small decrease in OH--conductivity due to the reduced water absorption. The OH--conductivities in the range of 2.7 ×10-4－1.52 ×10-3S cm-1were obtained at room temperature (19±2°C), depending on the polymer composition and the content of cross-linking agent. TG analysis showed that the membranes exhibited the thermal stability high up to 350°C when incorporating 75% QHECE. In addition, the membranes displayed a high alkaline stability without losing their integrity and OH--conductivity after conditioning in 6M KOH at 60°C for one week.