Nano Composite Membranes of Sulfonated Poly(Ether Ketone)/ Poly(Ether Sulfone) Copolymer and SiO_2 for Fuel Cell Application

摘要

Novel bisphenol-based wholly aromatic poly(ether ketone)/poly(ether sulfone) copolymers containing pendant sulfonate groups were prepared by direct aromatic nucleophilic substitution polycondensation of 4,4-difluoro-3,3'-disodiumsulfonylbenzophenone (40mol% of bisphenol), difluorophenylsulfone and bisphenol A. Organic-inorganic composite membranes were obtained by mixing organic polymers with hydrophilic SiO_2 (ca. 20nm) obtained by sol-gel process. The physic-chemical properties of these composite membranes were studied by thermogravimetry analysis(TGA), differential scanning calorimetry (DSC) and transform infrared(FTIR) spectroscopy. Scanning electron microscopy (SEM) and atomic Force microscopy (AFM) were used to observe the surface of membrances. The proton conductivity as a function of temperature decreased as SiO_2 content increased, but water uptake increased. The membranes were shown all requisite properties; IEC (1.5meq./g), thermal stablity (T_g= 185℃), and low affinity towards methanol (1.5×10~(-7) -4.3×10~(-7) cm~2/S).