Anisotropic thermal conductivity study of nano-additives/epoxy based nanocomposites

This study investigates the anisotropic thermal conductivity behavior of an tetrafunctional epoxy resin containing low percentages (at loading level from 0.25 to 2% wt) of different types of carbonaceous nanofillers, such as 1-D Multiwall Carbon Nanotubes (MWCNTs) and 2-D predominant shape of Exfoliated Graphite nanoparticles (EG). The Transient Plane Source (TPS) measurements shown that, for epoxy formulations filled with MWCNTs, the axial (through-plane) thermal conductivity increase about 60% with respect to the value shown by the resin alone while the radial (in-plane) thermal conductivity remains unchanged. The use of two-dimensional nanoparticles (EG) produces a more significant increase in the thermal conductivity value in both directions. These preliminary results indicate that in the analyzed nanocomposite formulations the thermal channels formed by the carbon nanotubes (MWCNTs) are predominantly along the axial direction whereas in the case of the exfoliated graphite (EG) they are distributed in both directions with a preference in the axial direction where the increase of thermal conductivity is about 250% at 2% wt of nanoparticles loading.