Phase separation in entangled polystyrene/poly(vinyl methyl ether) blends

Citation
S. Pavawongsak et al., Phase separation in entangled polystyrene/poly(vinyl methyl ether) blends, POLYMER, 41(2), 2000, pp. 757-763
Citations number
14
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
POLYMER
ISSN journal
0032-3861 → ACNP
Volume
41
Issue
2
Year of publication
2000
Pages
757 - 763
Database
ISI
SICI code
0032-3861(200001)41:2<757:PSIEPM>2.0.ZU;2-7
Abstract
The entanglement effects on the phase separation of polystyrene/poly(vinyl methyl ether) (PS/PVME) blends were studied by considering the viscoelastic relaxation time and the early stages of dynamic demixing. Particular inter est was focused on the blend in which the molecular weight of one component is much higher than that of the other component (M-w, (PS) >> M-w, (PVME)) The viscoelastic relaxation time of high molecular weight PS and PVME in t he blends can be clearly separated and the onset of the phase separation pr ocess after a temperature jump is delayed to a later time. We suggest that this is due to the formation of a temporary network of the well entangled p olymer which needs to relax before phase separation can occur. The results are in good agreement with the theoretical work reported previously by Clar ke et al. [Macromolecules 1997;30:4459]. For the blends containing low mole cular weight linear and 3-armed star molecules, the viscoelastic effects on the phase separation are not significant since the polymers are not effect ively entangled. (C) 1999 Elsevier Science Ltd. All rights reserved.