Electrical properties of a composite comprising epoxy resin and α-hematite nanorods

Electrical properties of pure epoxy and epoxy-hematite nanorod composites have been investigated. The nanorods were synthesized by the forced hydrolysis method and further mixed with epoxy to obtain the nanocomposite. TEM analysis revealed that they have an average diameter of about 8 nm, with an average aspect ratio of 25. DC-conductivity and DC-current relaxation measurements showed a significant influence of Fe2O3 nanorods on the DC-electrical properties of the epoxy matrix. However, the observed effects of the filler below and above the glass transition are different. Because of their high specific surfaces, nanorods affected segmental mobility of epoxy molecules to a large extent, which resulted in an increase in the glass transition temperature (Tg) and a decrease in the real part of dielectric permittivity in high frequency/low temperature region. It is further observed that at elevated temperatures (above Tg) and low frequencies the real part of dielectric permittivity of the nanocomposite exceeds that of the pure matrix, i.e. there is a transition towards microcomposite-like dielectric behaviour.