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ExxonMobil Chemical European Science & Engineering Award - € 40.000
ExxonMobil Chemical European Science & Engineering
Award - € 40.000
2 laureaten die elk € 20.000 krijgen. Uitreiking op 5
december 2007.
Prof. Jan Vermant, Katholieke Universiteit Leuven (B), winner of the ESEP European
Award ’07.
In the present work we have investigated
the flow-induced structuring in suspension of both spherical and non-spherical
nature. Model suspensions of colloidal and nano-sized particles in polymeric
media with controlled rheological properties have been studied, in situ and
time resolved using advanced optical, rheo-optical and scattering techniques.
The results reveal subtle, and sometimes unexpected effects of the rheology of
the polymeric matrix fluid. These include particle chaining for spherical
particles whereas for ellipsoidal particles, a cascade of orientational
transitions van be observed upon increasing flow strengths. Overall the work is
leading to a fundamental understanding of structure formation and rheological
properties of particle filled materials and nanocomposities. It is unique in
the sense that we have tried to systematically focus on isolating the effects
of medium rheology on the changes in the hydrodynamic forces acting upon and
in-between particles suspended in polymeric fluids.
Prof. Martin Zatloukal, Tomas Bata University, Zlin (CZ), winner of the ESEP European
Award ’07.
The effect of processing conditions, die
design and material characteristics on the flow stability in both
extrusion/coextrusion dies and post die areas has been investigated theoretically
by using Finite Element Methods or variational principles and the theoretical
predictions were compared with the corresponding experimental data. Specific
attention has been paid to three types of instabilities.
Die drool manifests itself as an undesirable
build-up of material, normally on the lip or open face of extrusion dies,
influencing significantly productivity and quality. The high value of negative
pressure occurrence at the die exit region can explain this.
In coextrusion, one of the main limiting
factors is the appearance of the interfacial instabilities in two forms:
‘wave’ and ‘zig-zag’. Stress variables have been
proposed to the bubble instabilities at particular processing conditions is a
known problem. A new film bowing model has been proposed by using variational
principles.