Synthesis and properties of chemically cross-linked polyvinyl alcohol)/quaterized hydroxyethylcellulose ethoxylate (PVA/QHECE) as novel alkaline anion-exchange membrane

摘要

A new type of chemically cross-linked polymer blend membranes consisting of polyvinyl alcohol) (PVA) and quaterized hydroxyethylcellulose ethoxylate (QHECE) have been prepared and evaluated as OH~--conducting polymer electrolytes. The OH~--conductivity (a) 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 x 10~(-4)-1.52 x 10~(-3) S cm~(-1) were 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.