Effect of same chloromethylation and sulfonation process on the ion exchange membranes in terms of polymer types and ionic properties

Abstract

Ionic membranes are known as dense membranes in which ions have transferred according to the desired purpose under an electrical current. In this study, sulfonation and chloromethylation processes were applied to different polymers and exchangers during the production phase of anion and cation exchange membranes. The results showed that the polysulfone-based anion and cation exchange membrane exhibited the lowest resistance of 0.268 Ω cm-2 and 0.71 Ω cm-2, the highest ion exchange capacities of 3.74 and 3.41 meq/g, and also the highest ionic conductivities of 28.3 and 10.76 mS/cm, respectively. On the other hand, the tensile strengths were measured for polystyrene-based anion exchange and poly(butadiene-co-styrene)-based cation exchange membranes 507 and 626.15 MPa. Although polystyrene and poly(butadiene-co-styrene) exhibited good results in terms of tensile strength, polysulfone-based AEM and CEM were the best in terms of ionic properties such as ion separation, permeability, and resistance. In addition, chloromethylation method with the mixture of formaldehyde and HCl has improved the resistance, ion exchange capacity, and ionic conductivity properties of AEMs compared to other chloromethylation methods.