Effect of Matrix Chemical Nature on the Properties of Composites for Microwave Absorbers

Abstract

Virgin and carbon black-filled composites have been prepared using two completely different matrixes – natural rubber (a non-polar, crystallizing elastomer) and nitrile butadiene rubber (a polar, non-crystallizing elastomer). The investigations reported reveal how the chemical nature of the rubber matrixes affects the dielectric (dielectric permittivity and dielectric loss angle tangent) and microwave (reflection coefficient, electromagnetic attenuation and electromagnetic shielding) properties of the obtained materials. The effects observed have been explained by the fact that interface polarization, relaxation processes, wetting and distribution of the absorption active filler are strongly dependent on the matrix character. The chemical nature of the matrix used predetermines composites properties through the effects related to the mechanisms of dielectric losses and electromagnetic interaction. The results obtained allow an appropriate choice of elastomeric matrixes for the production of composites designed for microwave absorbers.