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

• Novel anion exchange membranes with interpenetrated network (IPN) structure
• Increased tensile stress of the membrane with IPN structure
• Decreased methanol permeability of the prepared membranes
• High tolerance to alkaline solution of the membranes

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 0 wt.% to 40 wt.% in the full-IPN membrane, the tensile stress was increased from 30.1 MPa to 43.9 MPa, the methanol permeability was decreased from 6.64 × 10− 6 cm2 s− 1 to 6.54 × 10− 7 cm2 s− 1, respectively. Anionic conductivities of 6.00 × 10− 3–1.26 × 10− 2 S cm− 1 were achieved at 80 °C for the obtained membranes. To the membranes with a QCS content of 60 wt.%, the conductivity and tensile stress of about 90% were maintained after soaking the membranes in 1 mol L− 1 KOH for 120 h, and a 10 mol L− 1 KOH for 50 h at room temperature, respectively.