Development of a dispersion process for carbon nanotubes in an epoxy matrix and the resulting electrical properties

To avoid electrostatic charging of an insulating matrix an electrical condu ctivity above sigma = 10(-6) Sm-1 is needed. At present, the most common pr actice to achieve this conductivity is to use a conductive filler such as c arbon black. In this work, untreated catalytically-grown carbon nanotubes w ere dispersed in an epoxy matrix. After curing the epoxy, the electrical pr operties of the composite were measured in order to relate the filler volum e fraction to the electrical conductivity. The intense stirring process use d to disperse the carbon nanotubes has made it possible to achieve a matrix conductivity around sigma = 10(-2) Sm-1 with filler volume fractions as lo w as 0.1 vol.%. These figures represent an advance on best conductivity val ues previously obtained with carbon black in the same epoxy matrix. These l ow filler fractions ensure that the mechanical properties of the matrix are not compromised. (C) 1999 Elsevier Science Ltd. All rights reserved.