Anion exchange membranes based on poly (styrene-b-(ethylene-co-butylene)-b-styrene) grafted poly (2,6-dimethyl-1,4-phenylene oxide)

Poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) has been widely studied in the field of anion exchange membranes (AEMs) due to its superior flexibility and chemical stability, but the poor dimensional stability of functionalized SEBS restricts its further application. Thus, we adopt an effective strategy to reinforce AEMs based on SEBS via grafting poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) using Williamson ether synthesis reaction. With the addition of PPO, grafted membranes exhibit outstanding comprehensive properties, such as mechanical strength, chemical stability, especially dimensional stability. SEBS-PPO-QA-1 grafted membrane with the highest content of PPO showed the best tensile strength (20.54 MPa), and restrained swelling behavior (swelling ratio of 4.81% at 25°C). Moreover, the conductivity retention of SEBS-PPO-QA-1 grafted membrane is up to 92.71% at 80°C after 10 days alkaline treatment. The ion exchange capacity of SEBS-PPO-QA-3 grafted membrane is 1.719 mmol/g, and the ionic conductivity of SEBS-PPO-QA-3 grafted membrane reach 58.27 mS/cm at 80°C and 25.53 mS/cm at 20°C. Therefore, the SEBS-PPO-QA- X grafted membranes, which combine the advantages of PPO and SEBS, are promising in AEM application.