The effect of compressive strain and stress on electrical conductivity of conductive rubber composites

The electrical conductivity changes significantly when compressive strain a nd stress are applied on the conductive rubber composites derived from acry lonitrile-butadine rubber (NBR). ethylene-propylene-diene rubber (EPDM) and their 50:50 blend. The resistivity increases during application of compres sive strain. However, the change of electrical resistivity depends on strai n amplitude, amount of filler loading and type of polymer matrix. The chang e of resistivity with time for compressed samples has also been registered. But. during application of compressive stress (pressure), the resistivity is found to decrease for NBR and increase for EPDM and dual behavior is obs erved in blend. All the increase and decrease of resistivity with the appli cation of stress and strain is explained on the basis of formation and dest ruction of a conductive network. which further depends on viscosity (stiffn ess) of the matrices. The observations are supported by the similar experim ents with conductive silicone rubber composites.