The team aims to use and develop a knowledge in the field of rheology in connection with the morphology of polymers and their processing for a wide perimeter ranging from concepts at the molecular level until to the macroscopic level (descriptors of the structures and morphologies, constitutive equations) taking into account experimental problems (techniques and methods for rheological analysis, modelling of particular processing method especially reactive processing). The team is therefore widely recognized through its contributions in the domains of the rheology of polymer melts and the modelling of the various aspects of polymer processing.

The rheological topics addressed in past studies but that are always dealt with, concern :
• The linear and non-linear viscoelasticity of polymer melts, dynamics of polymer melts and correlation between the MWD and topology of branched materials,
• The linear viscoelasticity of polymer blends in the diluted and concentrated composition range and especially in the co-continous phase domain,
• The linear viscoelasticity of filled systems, including nano-fillers.
These questions are addressed for the purpose of understanding the dynamics of the melts and for the characterization of the polymer systems by the solving of the inverse problems. This can be combined with imaging or physico-chemical analysis (SEC, conducting and dielectric properties) in order to provide new techniques to characterize the polymers.

The processing topics focus on three main sides of the processing of polymers :
• The structuration of the polymers from the melt or in the melt, by controlling and changing the external constraints that are imposed on the melt : temperature (cooling), pressure, shearing, extension, drawing. The understanding of the events and kinetics such as crystallization, controlled segregation and localization of fillers, copolymer structuring, dispersion, phase arrangements is under the scope of the studies,
• The understanding of the relative actions of rheology, diffusion of reactants and chemistry is addressed in the case of reactive processing with special focus on in-situ generation of nanofillers, reactive blending or controlled plasticizing by ionic liquids or carbon dioxide,
• The modelling of particular processes such as reactive coextrusion, rotomolding, special mixing devices.
All these areas find some pragmatic applications towards up-to-date societal problems such as recycling or the use of green plasticizers or solvents.

This scope expands in three main research areas going from linear viscoelasticity to non-linear viscoelasticity in viscosimetric flow and finally to non-viscosimetric complex flows in processing. Besides, the materials under investigation becomes also more complex ranging from homogeneous medium, heterogeneous liquid-liquid, heterogeneous liquid-solid, to materials undergoing a desired on-purpose transformation, possibly of chemical nature.

Leaders : C. CARROT / R. FULCHIRON / A. MAAZOUZ