Acoustic, dielectric, and mechanical properties of a new rigid-rod poly(heteroarylene)

The structural, relaxational, and stress-strain properties of rigid-rod poly(heteroarylene)s containing high-polarity functional groups in macrochains are studied. The groups are capable of forming strong intermolecular bonds, including those with polar low-molecular substances (residual solvent or water). The acoustic and dielectric spectroscopy methods are used. The properties of a recently obtained poly(heteroarylene)—poly(naphthoyleneimidobenzimidazole)—are studied in detail. It is shown that these rigid-rod polymers can exhibit local and large-scale molecular rearrangements at temperatures considerably lower than the glass transition temperature. The frequency vs. temperature diagram of relaxation transitions is obtained, and the activation energies for these processes are determined. The possible molecular dynamics mechanisms are discussed.