Thermal, Mechanical and Electrical Investigation of Elastomer-Carbon Black Nanocomposite Piezoresistivity

Polymeric composites, where polymeric matrices are purposefully added with suitable fillers, have raised the interest of the scientific community, since materials with characteristics that depend on the nature of both the polymeric matrix and the filler can be obtained. The paper deals with the investigation of composites based on an insulating polymeric matrix, realized by using polydimethylsiloxane (PDMS) and carbon black (CB), as the filler, for realizing nanocomposites. The PDMS is an insulating matter, while the CB has conducting properties. If a suitable concentration of the CB is used, it is possible, therefore, changing the electrical properties of the composite from insulating to conducting. Such a possibility is, e.g. described in the framework of the percolation theory. Since a deformation of the composite causes a corresponding change in the concentration of the filler, it is possible using the described nanocomposites as piezoresistive elements. Based on the considerations reported above, composites were realized by using different concentrations of the filler, in order to obtain a reasonable value of the composite resistivity. The corresponding thermal, mechanical and electrical properties where, therefore, investigated in typical laboratory conditions.