being tailored. Both mechanical and electrical properties seem to
be more sensitive to the CNT concentrations and geometrical pa-
rameters when compared with thermal properties. For example,
Thostenson et al. 7 studied the influence of nanotube concentra-
tion on the electrical properties of the CNT/vinyl-ester compos-
ites. At a concentration of only 0.1 wt % of CNTs, the volume
resistivity decreased by over eight orders of magnitude. The limit
that governs the sudden transition between insulating and con-
ducting behaviors is known as the percolation threshold, which
will be given more attention in the coming discussions. Gojny et
al. 8 demonstrated that the addition of as little as 0.1 wt % of
CNTs in an epoxy matrix can increase the fracture toughness by
upward of 20% with further improvements observed for amino-
functionalized nanotubes. In comparison, the thermal conductivity
of cured nanotube-epoxy composites shows a minimal and near
insignificant increase with nanotube content, less that 0.5% for a
concentration of 0.5 wt % of CNTs 9.
http://www.mie.utoronto.ca/labs/madl/im ... 050801.pdf