A series of sulfonated polyimides were synthesized by condensation of bis(p-hydroxylphenyl)-1,4,5,8-naphthalenetetracarboxylic di-imide(NTDA) with various molar ratios of 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone to 4,4′-dichlorodiphenyl-sulfone. Both the monomers and the polymers were characterized by FTIR and {}+1H NMR. All the synthesized polymers have intrinsic viscosities above 0.70, which implies that the polymers have a high molecular weight. The DSC and TGA analysis of the polymers show that all of the polymers have good thermal stabilities. The polymers also have a good solubility, and could be cast into tough membranes. Some properties of the polymer membranes were also studied.
