Piezoresistivity - A powerful tool to monitor the behaviour of filler networks in rubber

Elastomers are often filled with various reinforcing particles to meet the desired performance measures, namely mechanical properties. These reinforcing filler particles, for example electrically conductive carbon allotropes, are used in quantities above the percolation threshold and thus form clusters or even filler networks that determine the ultimate performance of the final rubber product. Any changes or effects on the state of the filler network will immensely influence the performance of the rubber product. Therefore, lots of pioneer works could be found that study the changes of the filler network with respect to an external force (strain, temperature, etc.) and correlate to changes in mechanical & dynamic-mechanical properties. In our work an attempt is made to characterise changes in the integrity of filler networks inside rubber composites during mechanical loading in-situ by changes in electrical conductivity. Thus the dynamic piezoresistive characteristics were studied in detail on conducting rubber composites and temporal changes in the filler network could be correlated to the mechanical performance during dynamic deformation. The knowledge gained in our investigations will provide a potential tool for development of "self-sensing" rubber materials and future rubber based sensors suitable for dynamic loading conditions.