Green Fabrication of Tertrabutylammonium Styrene Sulfonate Cation-Exchange Membranes via a Solvent-Free Photopolymerization Strategy

A solvent-free UV-initiated free-radical photopolymerization was employed to synthesize a series of cation-exchange membranes (CEMs) based on tertrabutylammonium styrene sulfonate (SSTBA). A novel casting solution was formed by dissolving SSTBA and an initiator in a mixture of styrene and trimethylolpropane triacrylate monomers without any organic solvent. Polymerization and membrane formation were simultaneously progressed to obtain the cross-linked CEMs within only 15 min, and the electrochemical properties were not inferior to those of the commercial CEMs. The effects of SSTBA content on mechanical stability, ion-exchange capacity (IEC), water uptake, and membrane resistance were investigated. It was found that with the increasing content of SSTBA, the overall properties of membranes were improved. The practicability of prepared membranes was evaluated by desalination performance in electrodialysis. The membrane with the most superior performance exhibited IEC of 2.2 mmol·g–1, a resistance of 0.78 Ω·cm2, and a desalination ratio up to 99.3%, better than commercial CEMs. These results confirmed the possibility of preparing CEMs with an environmentally friendly strategy.