섬유

Effect of Hard Segments on Morphology of Polyurethanes

  • 출판일2001.02
  • 저자
  • 서지사항
  • 등록일 2016.11.02
  • 조회수 239
Experiments synthesized a series of thermoplastic polyurethanes with five diisocyanates and hydrogenated bisphenol A as the hard segments and polycarprolactone diol as the soft segment. Differential scanning calorimetry, wide angle X-ray diffraction, and small angle X-ray scattering analyses measured the effects of the hard segments on plyurethane morphology. The kinetic factors (hard segment mobility and system viscosty) controlled morphology in some of the samples. The polurethanes UMDI and UTDI had greater hard and soft segment incompatibility than such aliphatic diisocyanates as UHDI, IPDI, and HMDI based on their solubility parameters. Based on thermodynamics, phase separation should be more complete for polyurethanes with aromatic hard segments. Based on kinetics, however, phase separation became more complete with aliphatic hard segments due to their higher mobility and lower viscosity during the reaction and postcure process. 6 refs.
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