Preparation and Characterization of Anion Exchange Membrane Based on Polyhedral Oligomeric Silsesquioxane Star-Shaped Block Copolymers Containing Imidazolium Polymerized Ionic Liquid

Two polyhedral oligomeric silsesquioxane (POSS) star-shaped block copolymers POSS-(PMMA-b-PVIm)₈ with different PVIm blocks were synthesized, with POSS as intramolecular crosslinking point, polymethyl methacrylate (PMMA) and polyvinylimidazole (PVIm) as two blocks. Quaternization reaction and ion exchanging process of POSS-(PMMA-b-PVIm)₈ were followed subsequently to prepare anion exchange membranes (AEM), marked as PMV-1 and PMV-2.The water uptake (WU), swelling degree (SD), mechanical property, ion exchange capacity (IEC), conductivity (σ) of the two membranes were investigated. The WU and SD still remain appropriate level even at 90℃, the WU is 18.09% and 25.81%, the SD in the width is just 25.31% and 35.45% respectively. IEC of the membranes at 30℃ is 2.38 meq/g and 3.12 meq/g respectively. Both membranes exhibit good mechanical property and excellent conductivity, σ could reach 44.0 mS/cm and 255.0 mS/cm at 90℃. After immersion in 1 mol/L NaOH solution at 60℃ for 120 h, σ of PMV-1 membranes decreases no more than 30%.