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Rubber magnetic composites were prepared by incorporation of barium ferrite in constant amount—50 phr into acrylonitrile-butadiene rubber. Dicumyl peroxide as the curing agent was used for cross-linking of rubber magnets alone, or in combination with four different types of co-agents. The main aim was to examine the influence of curing system composition on magnetic and physical-mechanical properties of composites. The cross-link density and the structure of the formed cross-links were investigated too. The results demonstrated that the type and amount of the co-agent had significant influence on cross-link density, which was reflected in typical change of physical-mechanical properties. The tensile strength increased with increasing amount of co-agents, which can be attributed to the improvement of adhesion and compatibility on the interphase filler-rubber due to the presence of co-agents. Magnetic characteristics were found not to be influenced by the curing system composition. The application of peroxide curing systems consisting of organic peroxide and co-agents leads to the preparation of rubber magnets with not only good magnetic properties but also with improved physical-mechanical properties, which could broaden the sphere of their application uses. [ABSTRACT FROM AUTHOR]

Rubber magnetic composites were prepared by incorporation of unmodified and surface modified strontium ferrite into rubber matrices based on NBR and NBR/PVC. Strontium ferrite was dosed to the rubber matrices in concentration scale ranging from 0 to 100 phr. The main goal was to investigate the influence of the type of ferrite on the curing process, physical-mechanical and magnetic properties of composites. The mutual interactions between the filler and rubber matrices were investigated by determination of cross-link density and SEM analysis. The incorporation of magnetic fillers leads to the increase of cross-link density and remanent magnetic induction of composites. Moreover, the improvement of physical-mechanical properties was achieved in dependence on the content of magnetic fillers. Surface modification of ferrite contributed to the enhancement of adhesion on the interphase filler-rubber. It can be stated that ferrite exhibits reinforcing effect in the composite materials and this reinforcing behavior was emphasized with the increase in polarity of the rubber matrix. [ABSTRACT FROM AUTHOR]

Elastomeric magnetic composites were prepared by incorporation of strontium ferrite into polymer matrices based on natural as well as butadiene rubber. Besides the rubber and ferrite, or the combinations of ferrite and carbon black (in case of natural rubber), the model rubber compounds contained only ingredients which support curing process. The study was dedicated to the observation of fillers dispersion degree in the rubber matrices and investigation of physical-mechanical and magnetic properties of prepared composites. The results indicate that the dispersion degree of ferrite in the rubber matrices is not very high, but it can be positively influenced by the addition of carbon black. Despite of the fact that ferrite exhibits only low reinforcing effect on cross-linked elastomeric materials, physical-mechanical properties can be also positively influenced by the mutual change in combinations of both fillers (ferrite and carbon black). The prepared materials seem to have suitable magnetic and elastic properties. [ABSTRACT FROM AUTHOR]