Rheologica Acta

, Volume 44, Issue 1, pp 55–70 | Cite as

Morphology development in polystyrene/polyethylene blends during uniaxial elongational flow

  • Marcus Heindl
  • Maria-Kristin Sommer
  • Helmut Münstedt
Original Contribution
First Online:
Received:
Accepted:

Abstract

The deformation of linear low-density and low-density polyethylene particles dispersed in a polystyrene matrix was studied during defined uniaxial elongational flow conditions for different capillarity numbers and different temperatures. The morphology of the elongated samples was analysed by quenching the specimens in liquid nitrogen directly after the deformation. Furthermore, morphology development after recovery was investigated. By measuring the transient elongational viscosity of the blend matrix the true hydrodynamic stress during the flow process was calculated. Using a modified critical capillarity number, the fibril formation of the dispersed phase could be described at all test conditions. Virtually no break-up processes were observed. This finding could be explained by calculating the characteristic time of fibril break-up due to Rayleigh instabilities. By annealing the elongated samples a spherical shape of the dispersed droplets was regained. Compared with the initial sample morphology a pronounced increase of the particle sizes due to coalescence processes during elongation was observed.

Keywords

Polystyrene/polyethylene blends Uniaxial elongational flow Elongational viscosity Morphology development Capillarity number 
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Notes

Acknowledgements

The authors want to thank the German Research Foundation (DFG) for financial support of this work. For providing several types of oils used for the operation of the elongational rheometer, the authors would also like to thank G.E. Bayer Silicones Germany.

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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Marcus Heindl
    • 1
  • Maria-Kristin Sommer
    • 1
    • 2
  • Helmut Münstedt
    • 1
  1. 1.Institute of Polymer Materials, Department of Materials ScienceUniversity Erlangen-NürnbergErlangenGermany
  2. 2.Institut für KunststofftechnologieUniversity StuttgartStuttgartGermany

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