Rubber magnets based on NBR and lithium ferrite with the ability to absorb electromagnetic radiation

Abstract

Rubber magnetic composites were prepared through the incorporation of magnetic soft lithium ferrite into acrylonitrile butadiene rubber. Standard sulfur-based curing and peroxide curing systems were used for cross-linking of rubber matrices. The experimental part was focused on the investigation of ferrite content and curing system composition on cross-link density, physical-mechanical, magnetic and shielding characteristics of composites. The results demonstrated that cross-link density and physical-mechanical properties of composites can be modified by both the amount of ferrite and composition of the curing system. The influence of curing systems on magnetic properties was negligible. It can be stated that the application of lithium ferrite to rubber matrix leads to the preparation of rubber composites with the ability to efficiently absorb harmful electromagnetic radiation in the tested frequency range. The shielding efficiency of composites increased with increasing content of magnetic filler. K E Y W O R D S electromagnetic radiation shielding, magnetic filler, peroxide curing, rubber magnets, sulfur curing

Mechanical, Thermal, Electrical Characteristics and EMI Absorption Shielding Effectiveness of Rubber Composites Based on Ferrite and Carbon Fillers

“…It has been reported in scientic works that materials showing return loss at −10 dB can absorb 90-95% of EMI. The materials reaching return loss at −20 dB can efficiently absorb around 99% of electromagnetic radiation [26][27][28]. Figure 3 depicts the return loss of ferrite filled composites in the examined frequency range.…”

Electromagnetic absorption shielding effectiveness and physical‐mechanical properties of rubber composites

“…The experimental outputs have revealed the incorporation of those ferrites into polymers leads to the fabrication of composites that can efficiently shield electromagnetic radiation by absorption mechanisms. [35][36][37][38] Magnetic fillers were applied in concentration scale ranging from 100 to 500 phr. It was shown that the highest absorption shielding performance exhibited composites filled with 200 and 300 phr of ferrites.…”

“…In addition to laboratory prepared lithium and manganese zinc ferrite, commercially available nickel‐zinc ferrite and manganese‐zinc ferrite have been tested. The experimental outputs have revealed the incorporation of those ferrites into polymers leads to the fabrication of composites that can efficiently shield electromagnetic radiation by absorption mechanisms 35–38 . Magnetic fillers were applied in concentration scale ranging from 100 to 500 phr.…”

Influence of Combined Sulfur and Peroxide Curing Systems and Ageing on the Properties of Rubber Magnets

“…Due to their unique properties, they have been widely used as permanent flexible magnets, shielding devices, microwave absorbers or sensors of magnetic and electromagnetic fields. [1,2] Sulfur vulcanization of rubber compounds is a complex process, which leads to the formation of different types of sulfidic cross-links between macromolecules of rubber. Sulfur cured vulcanizates are characterized by high tensile and tear strength, good dynamic properties, but poor resistance to ageing and weak high temperature stability.…”

“…Due to their unique properties, they have been widely used as permanent flexible magnets, shielding devices, microwave absorbers or sensors of magnetic and electromagnetic fields. [ 1,2 ]…”