Thermal and mechanical properties of fiber‐forming poly(urethane semicarbazide)s

Fiber‐forming poly(urethane semicarbazide)s were prepared with poly(butylene adipate)glycol as soft‐segment domains and hexamethylene diisocyanate/terephthalic dihydrazide as hard‐segment domains. The hard‐segment content was varied via variations in the polyol/isocyanate molar ratio, and the films were characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. The effect of the hard‐segment‐content variation on the properties was studied by differential scanning calorimetry, stress–strain analysis, and dynamic mechanical testing. Differential scanning calorimetry showed that the samples exhibited a very low level of hard/soft‐segment phase mixing. The stress–strain analyses revealed that the elongation at break decreased with an increase in the hard‐segment content and that the mechanical property depended on the overall crystallinity of the samples. Dynamic mechanical tests revealed a high glassy‐to‐rubbery state modulus and a high degree of phase separation between the hard and soft segments.