Dielectric Properties of Closed Cell Microcellular Ethylene Propylene Diene Rubbers at Microwave Frequency

Microwave dielectric properties of closed cell microcellular EPDM rubber in shortcircuited wave-guide method have been studied at 9.69 GHz. Plots of dielectric constant (∊') with volume fraction of rubber shows a nonlinear relationship for both unfilled and silica filled microcellular rubbers obeying Weiner's inequalities. Several empirical relations have been tried to obtain a good fit. But for the solid vulcanizates other experimental values or points found to give a good fit. However the experimental fit found to deviate from the original empirical relation. A better fit was obtained for a proposed modified empirical relation suggested.