"Traditional damping polymers perform poorly at elevated temperatures," said Nikhil Koratkar of Rensselaer Polytechnic Institute. "Our new materials provide excellent damping at high temperatures, suggesting that these nanocomposites show great potential for a variety of applications in aircraft, spacecraft, satellites, automobiles and even sensors for missile systems - basically any structure that is exposed to vibration."

Koratkar and colleagues believe that the damping effect is produced by sliding at the interfaces between the polycarbonate matrix and the nanotubes. At higher temperatures this interfacial slip is activated more easily, boosting the effect.

The team made the nanotube-polycarbonate composites by a solution mixing process. They dissolved single-walled carbon nanotubes in tetrahydrofuran (THF) solution and polycarbonate in a separate THF solution. Following mixing of the two solutions in the correct proportions, the researchers precipitated the composite before hot pressing it to prepare tensile test specimens.

The researchers made composites with a weight fraction of 1.5% nanotubes. The resulting material contained bundles of single-walled carbon nanotubes, while each bundle had a diameter of around 35 nm.

The team tested the dynamic mechanical properties of the composites at temperatures of –60 to 90°C. For temperatures above 30°C the materials exhibited a higher loss modulus as the temperature increased.

The researchers reported their work in Nano Letters.