Resistivity behavior of carbon-black-filled silicone rubber in cyclic loading experiments

Stress–relaxation and cyclic loading behavior of silicone/EC black vulcanizates have been measured at several strains up to 0.8. The first extension is always very different from the subsequent ones. Orientation effects of anisometric carbon particles are starting to play an important role only after a certain elongation has been exceeded. The conductive elastomers can be stabilized by mechanical preconditioning procedures involving cycling at high extensions. The stabilized specimens then behaved nearly reversibly when cycled at strains below about 50% of the previous preconditioning strain. The resistivity-extension cycle consists of a single peak or a double peak per a strain peak depending on the strain level. The transition from single to double resistivity peaks depends on whether particle orientation takes place during the stretching process, which depends upon the level of strain.