SYNTHESIS AND CHARACTERIZATION OF POLYIMIDES FROM METAL-CONTAINING (BA, SR, PB, ZN)DIAMINES

Metal-containing polyimides with the metals in the main chain were prepared by firstly reacting pyromellitic dianhydride with a mixture of divalent metal salts of sulfanilic acid [ASA(M)] and 4,4'-diaminodiphenylmethane to form poly(amide acid) salts, the desired polyimides being obtained when the poly(amide acid) salts were separated from the solvent and heated under imidization conditions. The structures of the resulting polyimides were characterized by H-1 and C-13 nuclear magnetic resonance and infra-red spectroscopy, and their thermal properties by thermogravimetric analysis and dynamic thermal analysis. It was found that the inherent viscosity of the poly(amide acid) salt solutions decreased markedly with increasing metal content.