TITLE

Slow spinodal decomposition in binary liquid mixtures of polymers. V. Molecular weight dependence in the later stage of unmixing

AUTHOR(S)
Takenaka, Mikihito; Izumitani, Tatsuo; Hashimoto, Takeji
PUB. DATE
November 1992
SOURCE
Journal of Chemical Physics;11/1/1992, Vol. 97 Issue 9, p6855
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The unmixing process via spinodal decomposition of poly(styrene-ran-butadiene) (SBR)/polyisoprene (PI) mixtures was investigated by the time-resolved light-scattering method to see how it is affected by the temperature of phase separation T and by the molecular weight of PI with that of SBR fixed. Time changes in the wave number qm(t;T) and intensity Im(t;T) at the peak of the scattering function were followed to explore the coarsening process in the later stage of spinodal decomposition. For each mixture the observed changes at different T were reduced to a master curve when plotted against a reduced time Ï„. This finding is consistent with the scaling postulate by Langer et al. and Chou and Goldburg. The master curves for mixtures with different PI molecular weights were divergent, showing the phenomenon called the N branch. However, it was possible to bring them to a master curve when Ï„ was multiplied by a shift factor depending on the average number of entanglements per chain. The dependence was weaker than that predicted theoretically by Onuki.
ACCESSION #
7619562

 

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