Effect of High Aspect Ratio Fillers on the Performance of Styrene-Butadiene Rubber

ABSTRACT

Among the many material performance properties of vulcanized elastomers for tire tread application, rolling resistance and wet traction are particularly important since both greatly impact fuel efficiency and traction of a vehicle. Rolling resistance and wet traction are generally negatively correlated, i.e., with the increase in rolling resistance of a tire, its wet traction decreases. Silica nanofillers are often used for achieving the desired balance of wet traction and rolling resistance. However, the high cost of silica limits its wide spread application. In this research we studied the effects of using fillers with different aspect ratios (calculated by dividing the long dimension of a filler by its short dimension) on the performance of vulcanized styrene butadiene rubber (SBR), a common rubber for tire tread application. Three high aspect ratio fillers were used: aragonite calcium carbonate, wollastonite and carbon nanofiber. For comparison purpose, spherical silica filler was also included. We found that the high aspect ratio fillers were efficient in improving the wet traction and rolling resistance as well as enhancing the mechanical energy dissipation of SBR. Among the three high aspect ratio fillers studied, wollastonite provided the best wet traction and rolling resistance balance due to its high aspect ratio and compatibility with the base rubber. The effects of fillers induced crosslinking on the dynamic performance were also discussed.

KEYWORDS:

• Dynamic mechanical analysis
• filler aspect ratio
• rolling resistance
• SBR rubber
• wet traction

Acknowledgements

This work was supported by Independent Research and Development Funding (IRAD) by the Office of Technology Transfer of the Johns Hopkins University Applied Physics Laboratory (JHU/APL). Financial support for writing this paper was provided by the JHU/APL Research and Exploratory Development Department.