The Influence of Fillers Morphology and Distribution on the Mechanical Behaviour of Nano-Filled Elastomers

Nano-filled elastomer composites are used in a very broad range of applications such as tires, damping materials and impact modifiers. The addition of nanoscale rigid particles in a polymer matrix induces nonlinear effects that are not yet fully understood far above the glass transition temperature of the pure matrix.
A model of the reinforcement of nanocomposites [1] based on the reduced mobility of the polymer confined between two spherical filler particles [2] has been developed over the last ten years. In order to study the influence of the filler shape, structure, size, and dispersion state, we have extended the model were the morphology of the fillers is defined explicitly as spherical particles aggregated in the polymer matrix. The model is then solved by mesoscale numerical simulation in order to describe the mechanical properties of the nanocomposite.
We study the mechanical response of nanocomposite materials filled with aggregates of different shapes and distribution state to deformations of various amplitudes in the reinforcement regime.
We show that the mechanical behaviour of nanocomposites materials strongly depends on the filler morphology and we propose that stress-relaxation mechanisms in the material are related to the disorder (particle size, aggregation number, distribution state) in the filler population.
Our model opens the path for the development of systems with tailored properties by adjusting the fillers morphology.

[1] Merabia, S.; Sotta, P.; Long, D.R., Macromolecules 2008, 41, 8252-8266

[2] Dequidt, A.; Long, D.R.; Sotta, P.; Sanséau, O., Eur. Phys. J. E 2012, 35:61