Effects of different factors on the heat conduction properties of a nanostructured material comprising carbon nanotubes

Abstract

The increasing popularity of carbon nanotubes has created a demand for greater scientific understanding of the
characteristics of thermal transport in nanostructured materials. However, the effects of impurities, misalignments, and
structure factors on the thermal conductivity of carbon nanotube films and fibers are still poorly understood. Carbon
nanotube films and fibers were produced, and the parallel thermal conductance technique was employed to determine the
thermal conductivity. The effects of carbon nanotube structure, purity, and alignment on the thermal conductivity of carbon
films and fibers were investigated to understand the characteristics of thermal transport in the nanostructured material. The
importance of bulk density and cross-sectional area was determined experimentally. The results indicated that the prepared
carbon nanotube films and fibers are very efficient at conducting heat. The structure, purity, and alignment of carbon
nanotubes play a fundamentally important role in determining the heat conduction properties of carbon films and fibers.
Single-walled carbon nanotube films and fibers generally have high thermal conductivity. The presence of non-
carbonaceous impurities degrades the thermal performance due to the low degree of bundle contact. The thermal
conductivity may present power law dependence with temperature. The specific thermal conductivity decreases with
increasing bulk density. At room temperature, a maximum specific thermal conductivity is obtained but Umklapp scattering
occurs. The specific thermal conductivity of carbon nanotube fibers is significantly higher than that of carbon nanotube
films due to the increased degree of bundle alignment.