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Keywords:

  • glass transition;
  • polyurethanes;
  • dielectric properties

Abstract

Molecular mobility in castor oil based polyurethane was investigated with thermally stimulated depolarization current (TSDC) measurements and alternating-current (ac) dielectric relaxation spectroscopy. Three peaks could be observed in TSDC thermograms from 173 to 373 K. The relaxation located at 213 K could be attributed to the change in the molecular chain due to the interaction between the isocyanate and the solvent, and it was well fitted with the Vogel–Fulcher–Tammann equation. The other two peaks were located at 274 and 365 K and could be attributed to interfacial polarization and space charge, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 746–749, 2005