Carbon Nanotube Nanocomposites to Improve Rubber Mechanical Property

In recent years, there is an increasing demand for automobile to achieve high fuel economy (high gasoline mileage), which requires to use low-energy consumption and low rolling resistance tire.   Based on the data from U.S. Department of Energy, approximately 5-15% of the fuel consumed by a typical car may be used to overcome rolling resistance.  For heavy trucks, this quantity can be as high as 15%-30%. Low rolling resistance tires minimize wasted energy as a tire rolls, thereby decreasing required rolling effort - and in the case of automotive applications, improving vehicle fuel efficiency.

Carbon nanotubes are the strongest and stiffest materials in terms of tensile strength and elastic modulus, which are thought to be dreaming engineering materials. A multi-walled carbon nanotube is shown to have a tensile strength of 63 gigapascals (GPa).¹ In combination with its low solid density (1.3-1.4 g/cm^-3), the specific strength of carbon nanotube is 48,000 kN×m×kg^-1,² which is more than 300 times higher than that of high carbon steel (154 kN×m×kg^-1).  The high strength of carbon nanotubes make them attractive for applications as ultrastrong fibers.³ The carbon nanotubes, however, exhibit high tendency to form aggregate, due to strong van der Waals forces (or more specifically, pi-stacking).  The difficulty to uniformly disperse the nanotubes in the substrate has been preventing the full realization of their mechanical strengths. Our group recently find that carbon nanotubes can be processed into nanocomposites, which leads to decrease rubber rolling resistance and improve mechanical property.

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2. Collins, P. G.; Avouris, P. Nanotubes for Electronics. Scientific American 2000, 283, 62-69.

3. Stach, E. Nanomaterials: Nanotubes reveal their true strength. Nature Nanotechnology 2008, 3, 586-587