Effect of nickel-cobalt-zinc ferrite filler on electrical and mechanical properties of thermoplastic natural rubber composites

Thermoplastic natural rubber (TPNR) as polymer matrix was prepared by the melt blending method. Nickel-cobalt-zinc (NiCoZn) ferrite as a filler was prepared by the double-stage sintering method in air. The filler was incorporated in the polymer matrix using a Brabender internal mixer. The filler content was varied from 0 to 30 wt.%. The morphological study of the fractured surface using a scanning electron microscope (SEM) shows the effects of strain. The X-ray diffraction (XRD) indicates the coexistence of both the ferrite and thermoplastic. Electrical properties were studied using a high frequency response analyzer (HFRA) at room temperature (298 degrees K). The results show that resistivity (q) decreases, but the dielectric constant increases, with increasing filler content. The resistivity and dielectric constant for all the composites are in the range of 8.9 x 10(6) x 9.7 x 10(5) Omega m and 33-72, respectively. A sharp change in both quantities around 15 wt.% filler content is interpreted as due to the transition from a dispersed system to an attached system. The tensile study shows that the elongation at break point and the tensile strength of the composite at room temperature decrease with increasing filler content. The hardness of the samples decreases with increasing filler content.