Structure and Properties of Fatigued Segmented Poly(urethaneurea)s III. Quantitative Analyses of Hydrogen Bond

Abstract

Hydrogen bonds in segmented poly(urethaneurea)s (SPUU) were studied with Fourier transform infrared spectroscopy (FT IR). Absorption curves due to the urethane and urea carbonyl groups were resolved into several peaks by a peak resolving method. Evaluation of individual peak intensity enabled one to estimate the amounts of hydrogen bonds formed with urea and urethane carbonyl groups, referred to as hydrogen bond indices, HUA and HUT, respectively. HUA and HUT were defined as the ratios of absorbances of hydrogen bonded carbonyl groups to free carbonyl groups, respectively for urea (UA) and urethane (UT) carbonyl groups. It was found that the indices of hydrogen bonds of urethane and urea carbonyl groups were the parameters which represent phase mixing, i.e., dispersion of hard segments in the soft segment matrix, and the cohesive force in the hard segment domain. The variation of the indices of hydrogen bonds with increasing elongation and temperature indicated progress of the phase mixing and reduction of the cohesive force of the hard segment domain.