Mechanical and electrical properties of alumina–natural rubber composites

Abstract

The mechanical and electrical properties of natural rubber (NR)–alumina (Al₂O₃) composites crosslinked with dicumyl peroxide (DCP) were investigated. Scanning electron micrographs indicate the interaction of the C–C microstructure and that alumina particles are moderately dispersed in the matrix. The X-ray diffraction patterns indicate that Al₂O₃ is of the β phase polytype that possesses high ionic conductivity. The electrical conductivity of the composites with DCP is greater by nearly three orders of magnitude than that of NR–Al₂O₃ composites without DCP and pure NR. The increase in the electrical conductivity and the mechanical property is caused by the strong C–C bond, the tunnelling phenomenon and the ionic polarisation of the alumina particles acting as the dispersed phase in the elastomer matrix.