Data are presented which show that the critical volume loading of a metallic filler needed to induce electrical conductivity in a polymer matrix can be substantially reduced by adding the metal as randomly dispersed fibres. Higher aspect ratio fibres will induce conductivity at lower volume loadings. Composites exhibiting resistivities below 200 ohm cm have been prepared with as little as 7.7 volume percent aluminium fibres having an aspect ratio of 24 : 1. At such low filler loadings the mechanical properties of the composite are similar to those obtained with an identical loading of milled glass fibres. While aluminium is poorly wet by most virgin polymers, this characteristic can be improved by polymer modification and surface treatments. The thermal properties of these composites are shown to follow predictions based on Nielsen's theory. © 1979.
