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Segmental dynamics of reactively prepared polystyrene blends: Unsaturated polyester resin versus high impact polystyrene
Author(s) -
Qazvini N. Taheri,
Mohammadi N.
Publication year - 2007
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.26365
Subject(s) - polystyrene , fragility , materials science , composite material , polyester , dispersion (optics) , dynamic mechanical analysis , polymer chemistry , polymer , chemistry , physics , optics
Segmental dynamics of two phase‐separated reactively prepared polystyrene blends namely unsaturated polyester resin (UPR) and high impact polystyrene (HIPS) was investigated by dynamic–mechanical spectroscopy and calorimetric studies. The results showed a thermorheologically simple behavior for the HIPS, which could be quantified based on the KWW function with β KWW of 0.37. The UPR data, however, could not be evaluated using KWW function, even though lower β KWW than the HIPS was expected for it. Furthermore, the α‐dispersion of the UPR was considerably broader while its fragility index was comparable with the HIPS. Nonetheless, segmental dynamics comparison based on normalized Δ C p ( T g ) by molecular weight of the structural units of the studied systems showed much greater differences. Accordingly, the UPR was both kinetically and thermodynamically more fragile than the HIPS. The higher fragility of the UPR could be attributed to its larger relative cooperativity size and topological constraints. Finally, enhanced contrast in dynamic fragilities of two studied systems could be achieved if similar overall and local compositions could be made experimentally. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007