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Rheology and phase separation of poly(styrene-co-maleic anhydride)/poly (methyl methacrylate) blends Chopra, Divya
Abstract
The effects of shear flow on the phase behavior of a polymer blend with high glass transition temperature, Tg, constituents and small dynamic asymmetry (T,g contrast) were investigated using shear and capillary rheometry, complemented by differential scanning calorimetry and analysis of the extrudates. This blend is a lower critical solution temperature mixture of a random copolymer of styrene and maleic anhydride, SMA, and poly(methyl methacrylate), PMMA. Both shear-induced mixing, at low and very high shear rates, and shear-induced demixing, at moderate shear rates, were observed. A way to detect and isolate the degradation effects, which are predominant in SMA at high temperatures, and result in opaque but not necessarily phase-separated samples, is also presented. The methodology presented here for the determination of the shear-phase diagram in a flowing polymer blend should be applicable to any industrial mixture, and it is of particular value for assessing the effects of strong shear flow, relevant in processing applications. Furthermore the method of solution preparation, i.e., solution-cast versus melt-mixed samples, did not affect the Theologically determined demixing temperatures. Finally, a simple general thermodynamic model within the framework of Flory's statistical mechanical lattice model is presented for predicting the shear-induced phase changes in polymer fluids. Theoretical predictions of the shear-induced phase diagrams agree reasonably well with selected experiments with the systems polystyrene/dioctyl phthalate and poly(styrene-comaleic anhydride)/poly(methyl methacrylate).
Item Metadata
Title |
Rheology and phase separation of poly(styrene-co-maleic anhydride)/poly (methyl methacrylate) blends
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1998
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Description |
The effects of shear flow on the phase behavior of a polymer blend with high
glass transition temperature, Tg, constituents and small dynamic asymmetry (T,g
contrast) were investigated using shear and capillary rheometry, complemented
by differential scanning calorimetry and analysis of the extrudates. This blend is a lower
critical solution temperature mixture of a random copolymer of styrene and maleic anhydride,
SMA, and poly(methyl methacrylate), PMMA. Both shear-induced mixing, at low and very
high shear rates, and shear-induced demixing, at moderate shear rates, were observed. A way
to detect and isolate the degradation effects, which are predominant in SMA at high
temperatures, and result in opaque but not necessarily phase-separated samples, is also
presented. The methodology presented here for the determination of the shear-phase diagram
in a flowing polymer blend should be applicable to any industrial mixture, and it is of
particular value for assessing the effects of strong shear flow, relevant in processing
applications. Furthermore the method of solution preparation, i.e., solution-cast versus melt-mixed
samples, did not affect the Theologically determined demixing temperatures. Finally, a
simple general thermodynamic model within the framework of Flory's statistical mechanical
lattice model is presented for predicting the shear-induced phase changes in polymer fluids.
Theoretical predictions of the shear-induced phase diagrams agree reasonably well with
selected experiments with the systems polystyrene/dioctyl phthalate and poly(styrene-comaleic
anhydride)/poly(methyl methacrylate).
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Extent |
4817313 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-05-21
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0058531
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1998-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.