The explosive progress of electronic devices and communication systems results in production of undesirable electromagnetic pollution, known as electromagnetic interference. The accumulation of electromagnetic radiation in the space results in...

In the present work, composite materials were prepared by incorporation of manganese-zinc ferrite, carbon black and combination of ferrite and carbon black into acrylonitrile-butadiene rubber (NBR). For cross-linking of composites, standard sulfur-based curing system was applied. The main goal was to investigate the influence of the fillers on the physical-mechanical properties of composites. Then, the electromagnetic absorption shielding ability was investigated in the frequency range 1 MHz–3 GHz. The results revealed that composites filled with ferrite provide sufficient absorption shielding performance in the tested frequency range. On the other hand, ferrite behaves as an inactive filler and deteriorates the physical-mechanical characteristics of composites. Carbon black reinforces the rubber matrix and contributes to the improvement of physical-mechanical properties. However, composites filled with carbon black are not able to absorb electromagnetic radiation in the given frequency range. Finally, the combination of carbon black and ferrite resulted in the modification of both physical-mechanical characteristics and absorption shielding ability of hybrid composites.

In this work, rubber composites were fabricated by incorporation of manganese-zinc ferrite alone and in combination with carbon-based fillers into acrylonitrile-butadiene rubber. Electromagnetic parameters and electromagnetic interference (EMI) absorption shielding effectiveness of composite materials were examined in the frequency range 1 MHz–3 GHz. The influence of ferrite and fillers combination on thermal characteristics and mechanical properties of composites was investigated as well. The results revealed that ferrite imparts absorption shielding efficiency to the composites in tested frequency range. The absorption shielding effectiveness and absorption maxima of ferrite filled composites shifted to lower frequencies with increasing content of magnetic filler. The combination of carbon black and ferrite also resulted in the fabrication of efficient EMI shields. However, the EMI absorption shielding effectiveness was lower, which can be ascribed to higher electrical conductivity and higher permittivity of those materials. The highest conductivity and permittivity of composites filled with combination of carbon nanotubes and ferrite was responsible for the lowest absorption shielding effectiveness within the examined frequency range. The results also demonstrated that combination of ferrite with carbon-based fillers resulted in the enhancement of thermal conductivity and improvement of mechanical properties.

The aim of the work was the investigation of the effect of dicumyl peroxide and different types of co-agents on cross-linking and physical-mechanical properties of vulcanisates based on acrylonitrile-butadiene rubber. First, dicumyl peroxide was applied for cross-linking at different curing temperatures. Based on the achieved results, the optimum temperature and peroxide concentration was chosen for the next experiments, in which organic peroxide was combined with various Type I and Type II co-agents. The results revealed that Type I coagents take active part in vulcanisation process as they contribute to the increase in crosslink density of vulcanisates. This was reflected in the increase in modulus and hardness and the decrease in elongation at break of vulcanisates. The tensile strength was also improved by the application of Type I co-agents. On the other hand, the decrease in cross-link density and deterioration of physical-mechanical properties was recorded by application of Type II co-agents.

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