HIPS morphology

Responsible persons:


Contemporary work includes modelling of formation of High Impact Polystyrene (HIPS) morphology, known also as the "salami" morphology. This modelling is based upon the spinodal decomposition of an initially homogeneous two compound mixture of styrene and polybutadiene. The blend undergoes the phase separation after a reaction forms the third compound - polystyrene. A result of this modelling is the qualitative description of the polystyrene-polybutadiene structure.

In a multi-component system polymer/polymer and polymer/solvent a contra-Fickian diffusion may occur. Instead of dissolving of compounds against their gradient of concentration, as described by the Fick's law, the solution quickly divides into separated phases with considerably different compositions. This phenomenon is well known and used in industry for obtaining materials of daily use (HIPS). However the systematical investigation and modelling studies weren't published yet. Our goal is the development of the software able to sufficiently predict the evolution of HIPS structure formation. 

The illustration of obtained results is provided in the Figure 1. There is shown the decomposition into two separated phases at two different moments. The concentration profiles are obtained after 20 and 380 seconds of decomposition. The colours represent concentration of polystyrene. The red regions represent rising polystyrene phase and the blue regions represent the polybutaiene phase.


Published results:

Vonka M., Kosek J. Modelling the morphology evolution of polymer materials undergoing phase separation. Chemical Engineering Journal, 2012, 207-208, 895-905. 

Vonka M., Šeda L., Kosek J. Modelling of the High-Impact Polystyrene Morphogenesis. Polymer Reaction Engineering – 10th International Workshop, 2011, 302, 151–160.



Juraj Kosek
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+420 220 443 296

University of Chemistry and Technology Prague
Department of Chemical Engineering
Technicka 5
166 28 Prague 6
Czech Republic

University of West Bohemia
New Technologies Research Centre (NTC)
Univerzitní 8
306 14 Pilsen
Czech Republic