Material Characterization and Microwave Substrate Applications of Alumina-Filled Butyl Rubber Composites

Composites of butyl rubber with micron alumina (BRAL) and nanoalumina (BRnAL) have been prepared by sigma mixing. The stress-strain curves of both BRAL and BRnAL composites show the mechanical flexibility of the composites. The dielectric and thermal properties of both composites were studied as a function of ceramic loading. For 0.1 volume fraction of micron alumina loading, the composites have attained a relative permittivity (epsilon(r)) of 2.82 and loss tangent (tan delta) of 0.0023 at 5 GHz, and for the same volume fraction of nanoalumina content, the composite showed epsilon(r) of 3.15 and tan delta of 0.014 at 5 GHz.