Thermal conductivity of low density carbon aerogels

Carbon aerogels with densities ranging from 0.182 to 0.052 g/cm(3), pore sizes ranging from 88 to 227 nm, and particle diameters ranging from 20 to 13 nm were prepared. Thermal conductivity measurements by laser flash method indicate that the lowest thermal conductivity can be obtained at a density of 0.066 g/cm(3), in the temperature range from 100 to 300 A degrees C in air. The lowest thermal conductivity is 0.0263 W/m K at 200 A degrees C. The characteristic density, at which the lowest thermal conductivity can be obtained, is temperature dependent. At a higher temperature, a higher density carbon aerogel will be more efficient in the reduction of the total conductivity by reducing the radiative conductivity.