Dynamics of Hydrogen Bonds and Cross-Linked Structures in Polyurethane Film Observed by Terahertz Spectroscopy

Terahertz (THz) absorption spectra of the cross-linked polyurethane films are observed at the temperature between 30–180 °C. The obtained spectra show characteristic absorption band at 3 THz assigned as hydrogen bonded urethane group. Another band at 7 THz was assigned as intermolecular vibration of cross-linked structures between polymer chains. The temperature dependent spectra were analyzed by the perturbation correlation moving window two-dimensional spectroscopy (PCMW2D) to clarify the slight spectral change. The thermal behavior of the absorption intensities shows the dynamics of hydrogen bonds and cross-linked structures in the polyurethane films.