Cross-linking, mechanical, dynamical, and EMI absorption shielding effectiveness of NBR based composites filled with combination on ferrite and carbon based fillers

In the current study, manganese-zinc ferrite in a concentration scale ranging from 100 to 500 phr was incorporated into acrylonitrile-butadiene rubber having the constant amount of carbon black (20 phr) or carbon nanotubes (5 phr). The work was focused on the investigation of fillers combination on curing process, physical-mechanical, and dynamic characteristics of composites. The electromagnetic interference absorption shielding efficiency of composites was subsequently investigated at low frequencies. The results revealed that composites filled with a combination of ferrite and CB are able to efficiently shield electromagnetic radiation in the tested frequency range 1 MHz to 3 GHz, while electromagnetic interference absorption shielding performance of CNT/ferrite composites was insufficient. The reason can be attributed to the outstanding increase of electrical conductivity of composites filled with combination of ferrite and CNT. As the best absorption shielding material can be considered the CB/ferrite composite containing 100 phr of ferrite, as it exhibited the widest absorption frequency bandwidth at return loss of −10 and −20 dB. The presence of ferrite in composites resulted in the decrease of cross-link density, modification of curing characteristics and physical-mechanical properties, and no significant influence on glass transition temperature. © 2021 John Wiley & Sons Ltd.