Formation and evaluation of interpenetrating networks of anion exchange membranes based on quaternized chitosan and copolymer poly(acrylamide)/polystyrene

Abstract

A high-strength anion exchange membrane with a full interpenetrating network (full-IPN) structure was prepared from quaternized chitosan (QCS), polyacrylamide (PAM) and polystyrene (PS). The influences of the component content of the membrane and crosslinking degree of the QCS on the mechanical properties, anionic conductivity as well as methanol permeability of the membranes were investigated. The results indicated that the full-IPN structure as well as the presence of the hydrophobic PS could improve the mechanical properties and decrease the methanol permeability of the membrane. Corresponding to the increase in the content of PAM/PS (the molar ratio of PAM/PS was 1:1) from 0wt.% to 40wt.% in the full-IPN membrane, the tensile stress was increased from 30.1MPa to 43.9MPa, the methanol permeability was decreased from 6.64×10−6cm2s−1 to 6.54×10−7cm2s−1, respectively. Anionic conductivities of 6.00×10−3–1.26×10−2Scm−1 were achieved at 80°C for the obtained membranes. To the membranes with a QCS content of 60wt.%, the conductivity and tensile stress of about 90% were maintained after soaking the membranes in 1molL−1 KOH for 120h, and a 10molL−1 KOH for 50h at room temperature, respectively.