Permeability and durability effects of cellulose polymer variation in polymer inclusion membranes

This report describes the preparation of a series of new cellulose-based polymer inclusion membranes (PIMs) and compares their properties to those made with cellulose triacetate (CTA). The cellulose derivatives considered in this study include cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB) containing both high and low butyryl content, and cellulose tributyrate (CTB). PIMs were prepared containing bis-tert-butylcyclohexano-18-crown-6 as a metal cation carrier. Differences in ion permeability based on polymer type were investigated by monitoring K+ flux. Flux of K+ diminished with increasing size of the polymer side chains. The resistance of varying PIMs to hydrolysis under acidic and alkaline conditions was determined. It was found that the length of polymer alkyl chain is proportional to PIM durability under pH conditions favoring hydrolytic cleavage of the polymer β-glucosidic linkages.