Overview
The addition of nanoparticles in rubber tire tread is essential to improve the wear properties of the material but leads to an increase in rolling resistance. The substitution of carbon black by silica allows to limit the rolling resistance and the performances of the system are controlled primarily by two parameters:
- The Dispersion of the filler
- The load-polymer interface
The problem is that these two parameters are not independent and the dispersion is difficult to measure in industrial systems due to nanoparticles fractality.
The objectives of this project were therefore multiple:
- Study of a model where the particle dispersion system is measurable => elastomers reinforced with spherical silica;
- Comparison with a 'real' system;
- Better understand how to modulate the different system parameters in order to obtain materials with perfectly controlled properties.
Funding
Results
Thanks to the developed model systems, it was possible to determine the impact of dispersion on rolling resistance and adhesion properties.
A good dispersion of the filler causes:
- an increase of the reinforcement (in the linear regime) at temperatures corresponding to the adhesion phenomena => better adhesion
- a reduction of capacity at temperatures corresponding to the rolling resistance => decreased rolling resistance.
The effect of interface was also considered and it was possible that the presence of a coupling agent providing the bond between the filler and the matrix also improves both the rolling resistance and the phenomena of adhesion.
All these results made it possible to develop a model of mesoscopic elastomeric reinforcement loads taking into account the modification of the dynamic properties of the polymer in the vicinity of the loads.
The confinement of the polymer between the nanoparticles (controlled by the distance between loads, so the dispersion) and the interaction between the filler and the matrix (depending on the nature of the interface) completely determine the properties.