Preparation And Properties Of SEBS-Based Self-Crosslinked And Composite Anion Exchange Membranes

With the pollution of the environment and exhaustion of energy,fuel cell?FC?as a new energy conversion device attract a lot of attention wordwide.It includes proton exchange membrane fuel cell?PEM?and anion exchange membrane fuel cell?AEMFC?,featured the advantages of high efficiency and startup at room temperature,which can be widely used in portable power supply,automobile and other related fields.As an important component for anion exchange membrane fuel cells?AEMFCs?,anion exchange membranes?AEMs?should have good ionic conduction,stability in alkaline and oxidative environment and mechanical properties.SEBS,poly?styrene-ethylene-co-butylene-styrene?,has excellent chemical stability and low cost.And the phenyl groups on the side chains are easy to be modificated and linked to the quaternary amine groups.In this article,a serious AEMs were made by chemical crosslinking to build the crosslinking structure or compositing,and the AEMs also be twice quaternized to improve the chemical stability and OH^-conductivity.A SEBS and PTFE composite anion exchang membrane with tetramethyl guanidum?TMG?and trimethylamine?TMA?as fuctional groups was prepared.The chloromethylate SEBS and BTMG was characterized by ¹H-NMR.The polymers and resulting AEMs was characterized by FTIR.The resulting SEBS-BTMG-TMA/PRFE membrane with tensile strength was 60.2MPa and the elongation at break was 128.5%,and higher than SEBS-BTMG with the tensile strength was 20.2MPa and elongation at break was 48.7%.Furthermore,after immersion in Fenton?4ppm FeSO₄,10%H₂O₂?reagent for 9h,it still had 75%residual mass and 75%OH^-conductivity much better than SEBS-BTMG brocken after 3h.And the SEBS-BTMG-TMA/PTFE also had excellent alkaline stability.After immersion in 1 mol/L NaOH solution at 80?for 888h,it still had 92.8%OH^-conductivity.A SEBS based anion exchange membrane with tetramethyl guanidium?TMG?and trimethylamine?TMA?as functional groups and A cross-linked structure formed between CMSEBS and di-n-butylamine?DBA?was prepared.The optimal reacting time of TMA and SEBS-BTMG-DBA was determined by exploring the effects of different reaction time.The polymer and the resulting AEMs were characterized by FT-IR,respectively.Through the post-ammination reaction of SEBS-BTMG-DBA with TMA,resulting in SEBS-TMA-7h membrane with high OH^-conductivity of 51.5 mS/cm at 80?and the IEC of 1.41 mmol/g.This was much better than SEBS-BTMG with OH^-conductivity of 31.8 mS/cm at 80?and IEC of 0.39 mmol/g.Furthermore,SEBS-TMA-7h also had excellent alkaline stability,after immersioned in 1 mol/L NaOH solution at 80?for 510h,it still had 90%OH^-conductivity.