Simultaneous characterization of dielectric and dynamic-mechanical properties of elastomeric materials under static and dynamic load

Abstract

The inner dynamics of carbon black filled elastomeric material under static and dynamic load are examined by means of simultaneous dielectric and dynamic-mechanical analysis at room temperature. The experiments are performed on styrene butadiene rubber (SBR) samples filled with carbon black well above the dielectric percolation threshold. By increasing the mechanical load, a decrease in the conductivity is found due to continuous mechanical damage to the filler network structure, which prevents the transport of charge carriers through the sample via the carbon black network. The Cole-Cole equation is applied to fit the experimental data. The resulting fit-parameters show different load dependence. The mechanical damage to the filler network makes the relaxation processes broader and leads to higher relaxation times, whereby the relaxation strength increases. This has been attributed to an increase in the correlation length of the filler network with increasing load.