Prof. Evelyne van Ruymbeke

Universite catholique de Louvain, Louvain la Neuve, Belgium

Understanding and modelling the dynamics of entangled, linear associative polymers melts.

Abstract
Associating polymers consist of polymer chains that carry functional groups. 
These functional groups are capable of forming transient interactions/bonds, 
which provide a convenient control of the physical properties of this class of 
polymeric systems. For example, depending on the temperature or/and the concentration 
of functional groups, the rheological behaviour of associative polymers ranges from rubber-like to liquid-like.
We focus on melts of entangled, linear associative polymers. In order to model their viscoelastic properties, 
we extend our tube based model that successfully predicts the linear viscoelasticity of ordinary, i.e. non-associative, 
polymer melts, in order to account for the stickers along the chains. These last ones give rise to a slow stress relaxation process, 
which is impossible to capture by ordinary reptation. To describe the dynamics of the system at intermediate frequencies (timescales), 
we show that tension equilibration must be considered, which is a slow Rouse-like relaxation process along the entangled chains, 
due to the blinking nature of the mobile polymer fraction. A detailed comparison between experimental data and model predictions 
is performed for different supramolecular systems.


Date: 26/5/2015
Time:12:30 (coffee & cookies will be served at 12:15)
Place:FORTH Seminar Room 2