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Phase behavior and molecular mobility in polyurethane/styrene–acrylonitrile blends
Author(s) -
Vatalis A. S.,
Kanapitsas A.,
Delides C. G.,
Viras K.,
Pissis P.
Publication year - 2001
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1192
Subject(s) - dynamic mechanical analysis , materials science , differential scanning calorimetry , glass transition , copolymer , acrylonitrile , polyurethane , polymer blend , polymer chemistry , thermal analysis , styrene , polymer , composite material , thermal , thermodynamics , physics
Differential scanning calorimetry (DSC), thermally stimulated depolarization currents (TSDC) techniques, dielectric relaxation spectroscopy (DRS), and dynamic mechanical thermal analysis (DMTA), covering together a wide range of temperatures and frequencies, were employed to investigate molecular mobility and microphase separation in blends of crosslinked polyurethane (PUR) and styrene–acrylonitrile (SAN) copolymer, prepared by reactive blending with polymer polyols. The results by each technique indicate that the degree of microphase separation of PUR into hard‐segment (HS) microdomains and soft‐segment (SS) microphase increases on addition of SAN. The various techniques were critically compared to each other, with respect to their characteristic time and length scales, on the basis of activation diagrams (Arrhenius plots). The results show that for the dynamic glass transition of the PUR SS microphase the characteristic time scales at the same temperature are similar for DMTA, DSC, and TSDC and shorter for DRS. In terms of fragility, the PUR/SAN blends are classified as fragile systems. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1071–1084, 2001

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