Specific rheological and electrical features of carbon nanotube dispersions in an epoxy matrix

The rheological analysis of epoxy pre-polymer/MWCNT dispersions indicates that a physical network is formed. This is destroyed with an imposed shear, giving a viscoplastic and shear thinning behavior. Such destruction is not reflected in dynamic viscoelastic experiments, due to the very rapid recovery of the MWCNT network in the pre-polymer matrix. This responds to the observed lower electrical than rheological percolation threshold. Electrical conductivity results fulfill electron hopping/tunnelling mechanism, which implies a tube-tube distance close to 5. nm. However, rheological percolation requires nanotubes should touch each other, since no polymer chains are implied in the network.