Electrical conductivity behaviour of sheared poly(methyl methacrylate)/carbon black composites

The electrical conductivity behaviour of unsheared (static) and sheared poly(methyl methacrylate)/carbon black (CB) composite disc-shaped samples with various CB concentrations as a function of the radial position were investigated and analysed. It was found that the angular averaged electrical conductivity of the static samples is independent of the radius and CB concentration. In comparison to that, the angular averaged electrical conductivity of the samples with a shear history is decreasing as a function of the radius due to the linear increase of the deformation from the centre to the rim of the samples. It is shown, that this effect is less pronounced increasing the composite concentration. A simple model is proposed to explain this behaviour. The results obtained in this study are in a very good agreement with the investigations performed via coupled electrical and rheological measurements and provide a deeper insight into structural changes in conductive polymer composites induced by shear deformations.