Multi-scale dynamics of filler particles and polymer in nanocomposites – NANODYN
Multi-scale dynamics of filler particles and polymer in nanocomposites.
The general goal of this project is to improve our understanding of the multi-scale dynamical properties of nanocomposites of industrial relevance, made with an industrial filler and a typical car tire polymer. Elucidating the complex structure and dynamics of the material at the different scales and their impact on the macroscopic material properties is a challenge for fundamental scientists, an economic necessity for industry, and an ecological imperative for society.
Understand basic phenomena of mechanical reinforcement and dissipation by studying an industrially relevant nanocomposite system.
The current discussion on the European regulation of CO2 emission of cars illustrates that it is urgent to reduce the contribution of car tires which amounts to some 20%. The phenomena of viscous dissipation – at the origin of parts of fuel consumption and thus CO2-emission –, but also of other properties like wear and grip, have their origin in the relaxation modes of nanocomposites in tires at very different time (or frequency) scales. These materials - polymer matrices with embedded nanoparticles, like e.g., silica – have a complex macroscopic behavior: dissipation, for instance, is described by rheology, but its understanding necessitates taking into account relaxation mechanisms with origins in 10^10 times quicker processes. The aim of the present project is to study a system close to the industrial application, based on a styrene-butadiene-polymer, filled with strongly aggregated industrial silica. For comparison, we will study in parallel a chemically similar reference system containing spherical silica nanoparticles well-defined in size. After a first task of formulation of samples of both types, followed by a detailed structural characterization based on a quantitative approach coupling small-angle scattering and electron microscopy, we propose to combine seven experimental approaches (rheology, dielectric spectroscopy, dynamic light scattering, atomic force microscopy, nuclear magnetic resonance, X-ray photon correlation, quasi-elastic neutron scattering) in order to grasp the multi-scale character of the dynamics of these nanocomposites, allowing for a deeper understanding of all dissipative relaxations of these complex materials.
The techniques used for studying the large dynamic and structural range of these materials are small-angle scattering and electron microscopy coupled to simulations for structure, and rheology, dielectric spectroscopy, dynamic light scattering, atomic force microscopy, nuclear magnetic resonance, X-ray photon correlation, and quasi-elastic neutron scattering for dynamics. These techniques cover large time and length scales, and the probes are sensitive to different entities within the samples (filler nanoparticles, polymer, ions, ...). These methods are thereby sensitive to local relaxations of polymer on the nanometer scale, then cover dipole and charge fluctuations on scales bridging molecular sizes to filler aggregates (dielectric spectroscopy), whereas light scattering is sensitive to nanometric to microscale reorganizations of filler nanoparticles, and rheology to a combination of chain reptation, polymer relaxation mechanisms at interfaces, and filler displacements.
First measurements of the filler mobility in nanocomposite by light scattering techniques. Such measurements lead to a direct link between the microscopic filler dynamics and the mechanical (macroscopic) properties.
Development of a new model system allowing to mix hydrophilic silica and hydrophobic polymer with different coating agents. This will allow tuning the interfacial contribution and possibly filler dispersion.
1. «International workshop on Nanocomposites and Polymer Dynamics«, Montpellier, 22-24 Juin 2015. Local organization committee: A.C. Genix, J. Oberdisse and C. Eve. Ca. 50 participants.
The current discussion on the European regulation of CO2 emission of cars illustrates that it is urgent to reduce the contribution of car tires which amounts to some 20%. The phenomena of viscous dissipation – at the origin of parts of fuel consumption and thus CO2-emission –, but also of other properties like wear and grip, have their origin in the relaxation modes of nanocomposites in tires at very different time (or frequency) scales. These materials - polymer matrices with embedded nanoparticles, like e.g., silica – have a complex macroscopic behavior: dissipation, for instance, is described by rheology, but its understanding necessitates taking into account relaxation mechanisms with origins in 10^10 times quicker processes.
The aim of the present project is to study a system close to the industrial application, based on a styrene-butadiene-polymer, filled with strongly aggregated industrial silica. For comparison, we will study in parallel a chemically similar reference system containing spherical silica nanoparticles well-defined in size. After a first task of formulation of samples of both types, followed by a detailed structural characterization based on a quantitative approach coupling small-angle scattering and electron microscopy, we propose to combine six experimental approaches (rheology, dielectric spectroscopy, dynamic light scattering, nuclear magnetic resonance, X-ray photon correlation, quasi-elastic neutron scattering) in order to grasp the multi-scale character of the dynamics of these nanocomposites, allowing for a deeper understanding of all dissipative relaxations of these complex materials.
Project coordination
Anne-Caroline Genix (Université Montpellier 2 - Laboratoire Charles Coulomb)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
Partner
L2C Université Montpellier 2 - Laboratoire Charles Coulomb
Help of the ANR 199,784 euros
Beginning and duration of the scientific project:
September 2014
- 42 Months
