Curing, Properties and EMI Absorption Shielding of Rubber Composites Based on Ferrites and Carbon Fibres

In this work, magnetic soft ferrites, namely manganese–zinc ferrite, nickel–zinc ferrite and combinations of both fillers, were incorporated into acrylonitrile-butadiene rubber to fabricate composite materials. The total content of ferrites was kept constant—300 phr. The second series of composites was fabricated with a similar composition. Moreover, carbon fibres were incorporated into rubber compounds in constant amount—25 phr. The work was focused on investigation of the fillers on absorption shieling performance of the composites, which was investigated within the frequency range 1–6 GHz. Then, the physical–mechanical properties of the composites were evaluated. The achieved results demonstrated that the absorption shielding efficiency of both composite types increased with increasing proportion of nickel–zinc ferrite, which suggests that nickel–zinc ferrite demonstrated better absorption shielding potential. Higher electrical conductivity and higher permittivity of composites filled with carbon fibres and ferrites resulted in their lower absorption shielding performance. Simultaneously, they absorbed electromagnetic radiation at lower frequencies. On the other hand, carbon fibres reinforced the rubber matrix, and subsequent improvement in physical–mechanical properties was recorded.