Synthesis, Characterization and Fuel Cell Application of Polyimides

Proton conducting polyimides containing pendant benzimidazole groups have been synthesized by different ratios of 5-(1H-benzimidazol-2-yl)-benzene-1-3-diamine (DABI) and oxydianiline (ODA) in the presence of oxydianiline (ODPA). All the polymers were structurally characterized by Fourier transform infrared (FT-IR) spectroscopy while the thermal properties were studied by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). From application point of view, proton conductivity of all polymers doped with phosphoric acid was studied by impedance analyzer. All the polymers have been found to be thermally stable with high dielectric constants and are proton conductive. The polymer with highest DABI value showed highest conductivity (max 0.11 S/cm). Keywords: Dielectrics, polymers, proton conductivity, thermal properties, fuel cell, thermodynamic limitation, pollution, oxygen solubility, benzimidazole ring, spectroscopy technique