Properties of Heterocyclic Condensation Polymers

Basic questions concerning heterocyclic polymers are reviewed. Initial investigations on the heterocyclic polymer BBB prepared from napthalene-1,4,5,8 tetracarboxylic acid and 3,3′-diaminobenzidine are described. These include infrared absorption studies of the structure of the polymer, fractionation of the polymer by exclusion chromatography on a porous substrate, and light scattering and dilute solution viscometry on fractions of the polymer dissolved in a strong acid. These data are interpreted to conclude that: (1) in dilute solutions BBB behaves as a “flexible coil” macromolecule, with perhaps relatively free rotation about the single bond connecting the long, inflexible, nearly planar repeat units; (2) a sufficient amount of interchain complex formation occurs in the solid state to give the linear, noncrystalline polymer some of the physical properties of a highly cross-linked network polymer.