High Aspect Ratio Nanofillers for Improving the Balance between Rolling Resistance and Wet Traction in Tires or Like Materials

Reference#: P03636

Rolling resistance and wet traction are two of the most important performance features for tire selection. It has been reported that rolling resistance consumes approximately 33% of wheels’ total usable energy, and the value increases at lower travelling speeds of less than 60 mph (DOT US811 154 August, 2009). Optimizing rolling resistance and wet traction is a critical challenge of tire manufacturing.

In today’s carbon-black-filled system, most tire technologies will improve one property at the expense of the other. With introduction of silica, the balance between wet traction and rolling resistance can be improved, but the wet trailer slide traction in silica system is not optimized because of frequency dependency (Rubber Chemistry and Technology 1999, volume. 72, page. 5). We have conceived a novel way of improving the balance between rolling resistance and wet traction through the addition of nano-size silica rods and silica nanofiber.

Because of the high aspect ratio in these nano-size silica structures, according to the Halpin–Tsai model, the stiffness of the formulation/rolling resistance will be improved and the high energy loss in the nano-silica structures will be maintained. Another interesting phenomenon that we have found is the excellent mechanical damping characteristics based on dynamic mechanical property derived from poly(lactic acid) (PLA) nano-size fibers, which show the high damping characteristics in the pure nanofiber web. This feature will reduce the noise level in the vehicles.

We plan to use the commonly used sio2 filler but with different morphology for improving the overall rubber stiffness—i.e., lowering the rolling resistance—and, because of the hydrophilicity of silica, the wet traction will improve at the same time. The Johns Hopkins Applied Physics Laboratory is well equipped to make these nano-sized silica structures (electro-spinning) and has a well-established sol-gel process for making them.

Our novel technology will revolutionize current tire manufacturing technology and, as a result, reduce vehicle fuel consumption, enhance vehicle control at high speed and in wet road conditions, improve long-term wear on tires, and reduce noise. We envision excellent dual use potentials for this technology both for military vehicles like Humvees and tank track pads and for commercial tires and specialty tires for racing.

Patent Status: U.S. patents pending.

Mr. K. Chao
Phone: (443) 778-7927

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