This thesis consists of a feasibility study on the use of carbon nanotubes as fillers in epoxy resins. The study is oriented towards the fabrication of epoxy composites that are both mechanically robust and thermally conductive. The specificity of this work is to evaluate the effects of functionalizing the carbon nanotubes before insertion into the epoxy matrix. Among the different chemical routes explored, a method consisting of covalently bonding functional molecules on carbon nanotubes is selected.