Rheological Properties of Conductive Polymer Composites around the Electrical Percolation Threshold

The electrical conductivity of polymeric materials containing conductive particles ows a typical percolation behavior. Besides this effect adding the particles to a polymer matrix affects the rheological properties considerably. In the literature one can find some studies relating the electrical percolation to a comparable change of rheological quantities. The term "theological percolation" is introduced; however, its delmition is not consistent in the literature. In this contribution some literature data obtained from dynamic -mechanical measurements are discussed and confronted with own data from oscillatory and creep -recovery measurements. From a critical evaluation of the data it follows that rheological properties change continuously with the filler content in the range of the electrical percolation threshold. A simple model is proposed to explain the differences between the electrical and rheological behavior of polymer composites.