Korea-Australia Rheology Journal

The Korean Society of Rheology (한국유변학회)
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Coalescence behavior of dispersed domains in binary immiscible fluid mixtures having bimodal size distributions under steady shear flow

  • Takahashi Yoshiaki (Department of Molecular and Material Sciences, IGSES, Kyushu University) ;
  • Kato Tsuyoshi (Department of Molecular and Material Sciences, IGSES, Kyushu University)
  • Published : 2005.09.01
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Abstract

Coalescence process of binary immiscible fluid mixtures having bimodal size distributions, prepared by mixing two pre-sheared samples at different shear rates, ${\gamma}_{pre1}\;and\;{\gamma}_{pre2}$, under shear flow at a final shear rate, ${\gamma}_f$, are examined by transient shear stress measurements and microscopic observations in comparison with the results for simply pre-sheared samples having narrow size distributions (unimodal distribution samples). Component fluids are a silicone oil (PDMS) and a hydrocarbon-formaldehyde resin (Genelite) and their viscosities are 14.1 and 21.0 $pa{\cdot}sec$ at room temperature $(ca.\;20^{\circ}C)$, respectively. The weight ratio of PDMS: Genelite was 7:3. Three cases, $({\gamma}_{pre1}=7.2sec^{-1},\;{\gamma}_{pre2}=12.0sec^{-1}\;and\;{\gamma}_f=2.4sec^{-1}),\;({\gamma}_{pre1}=0.8sec^{-1},\;{\gamma}_{pre2}=4.0sec^{-1}\;and\;{\gamma}_f=2.4sec^{-1}),\;and\;({\gamma}_{pre1}=7.2sec^{-1},\;{\gamma}_{pre2}=12.0^sec^{-1}\;and\;{\gamma}_f=7.2sec^{-1})$ the first case, transient shear stress did not show any significant difference but domains larger than the initial state are observed at short times. In the latter cases, there exist undershoot of shear stress, reflecting existence of deformed large domains, which is confirmed by the direct observation. It is concluded that coalescence between large and small domains more frequently occur than coalescence between the domains with similar size in the bimodal distribution samples.

Keywords

References

  1. Doi, M. and T. Ohta, 1991, Dynamics and rheology of complex interfaces. I, J. Chem. Phys. 95, 1242-1248 https://doi.org/10.1063/1.461156
  2. Kitade, S., A. Ichikawa, N. Imura, Y. Takahashi and I. Noda, 1997, Rheological properties and domain structures of immiscible polymer blends under steady and oscillatory shear flows, J. Rheol. 41, 1039-1060 https://doi.org/10.1122/1.550871
  3. Nakatani, A.I. and M.D. Dadmun, 1995, Flow-induced structure in polymers, American Chemical Society, Washington DC
  4. Rusu, D. and E. Peuvrel-Disdier, 1999, In situ characterization by small angle light scattering of the shear-induced coalescence mechanisms in immiscible polymer blends, J. Rheol. 43, 1391- 1409 https://doi.org/10.1122/1.551051
  5. Takahashi, Y., N. Kurashima, I. Noda and M. Doi, 1994a, Experimental tests of the scaling relation for textured materials in mixtures of two immiscible fluids, J. Rheol. 38, 699-712 https://doi.org/10.1122/1.550481
  6. Takahashi, Y., S. Kitade, N. Kurashima and I. Noda, 1994b, Viscoelastic properties of immiscible polymer blends under steady and transient shear flows, Polymer J., 26, 1206-1212 https://doi.org/10.1295/polymj.26.1206
  7. Takahashi, Y. and I. Noda, 1995, Domain structures and viscoelastic properties of immiscible polymer blends under shear flow, ACS Symposium Series 597, 140-152 https://doi.org/10.1021/bk-1995-0597.ch010
  8. Takahashi, Y., M. Suzuki and I. Noda, 2000, Examination of condition for fine structure of immiscible polymer blends by step change of shear rate, Zairyo (J. Soc. Materials Sci., Japan) 49, 1286-1290 https://doi.org/10.2472/jsms.49.1286
  9. Takahashi, Y. and Y. Akazawa, 2005, Hysteresis in domain size of imamiscible polymer blends under shear flow and the related viscosity behavior, Nihon Reoloji Gakkaishi (J. Soc. Rheol. Japan) 33, 17-21 https://doi.org/10.1678/rheology.33.17
  10. Takahashi, Y. and T. Kato, 2005, Coalescence behavior of dispersed domains in imamiscible polymer blends having broad size distribution, Nihon Reoloji Gakkaishi (J. Soc. Rheol. Japan) 33, 37-39 https://doi.org/10.1678/rheology.33.37
  11. Taylor, G.I., 1932, The viscosity of a fluid containing small drops of another fluid, Proc. R. Soc. London. Ser. A 138, 41-48 https://doi.org/10.1098/rspa.1932.0169
  12. Taylor, G.I., 1934, The formation of emulsions in definable fields of flow, Proc. R. Soc. London. Ser. A 146, 501-523
  13. Utracki, L.A., 1989, Polymer alloys and blends, Hanser, Munich
  14. Vinckier, I., P. Moldenaers and J. Mewis, 1996, Relashonship between rheology and morphology of model blends in steady shear flow, J. Rheol. 40, 613-631 https://doi.org/10.1122/1.550800