Synthesis of Sulfonation Poly(-propylsulfonicacid isatin biphenylene) for Polymer Electrolyte Membrane Fuel Cell Containing SiO₂ Nanocomposite Membrane.

Polymer containing isatin was synthesized by super acid-catalyzed carbon-carbon coupling reaction. Propylsulfonic acid was grafted on isatin unit by substitution reaction with potassium salt of 3-bromo-1-propanesulfonic acid. The sulfonic acid composition was regulated at 25~80 mol% of propylsulfonic acid in order to achieve expected ion exchange capacity of maximum 2.