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Rheo‐Optical behavior of binary polymer blends: The effect of simple shear flow on phase behavior
Author(s) -
Chen Z. J.,
Wu R.J.,
Shaw M. T.,
Weiss R. A.,
Fernandez M. L.,
Higgins J. S.
Publication year - 1995
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760350112
Subject(s) - materials science , polystyrene , shearing (physics) , shear rate , lower critical solution temperature , upper critical solution temperature , polymer blend , shear flow , polymer , rheometer , light scattering , shear (geology) , streak , optical microscope , composite material , phase (matter) , scattering , optics , polymer chemistry , thermodynamics , rheology , scanning electron microscope , chemistry , physics , organic chemistry , copolymer
The phase behavior of polymer blends under simple shear flow has been studied using a custom‐designed rheo‐optical system consisting of a two‐dimensional small‐angle light scattering (SALS) device incorporated into a conventional rheometer. Two‐dimensional SALS images were gathered for model polymer blend systems with different quiescent phase behavior: polystyrene/polyisobutylene (PS/PIB) that exhibits upper critical solution temperature phase behavior and polystyrene/poly(vinyl methyl ether) (PS/PVME) that shows lower critical solution temperature phase behavior. For the PS/PIB blend, shear‐induced phase mixing occurred at a critical shear rate. Below that critical shear rate, the dispersed phase was highly elongated parallel to the flow direction. For PS/PVME blends, a streak scattering pattern was observed even though the sample became optically clear after shearing. We observed, apparently for the first time, the development of a bright‐streak pattern from a transient dark‐streak pattern for a polymer blend system under shear. Rheo‐microscopy studies revealed an intriguing wave pattern that developed coincident with the observation of a streak pattern by SALS. The relationship between the two phenomena has not yet been established.