Interfacial interactions in rubber-based composites

The interfacial region of nitrile butadiene rubber matrix composites filled with magnetite and carbon black particles was studied. Raman spectroscopy was used as an alternative to study the filler-matrix interface behaviour. It was found that the amount of magnetite and its size (nano or micro) induce variations in the stress transfer between the fillers and the matrix. Stress propagation altered the graphitic domains of the carbon black that fill the matrix and induced shifts in position, changes in width, and intensity of the D and G bands. The XPS high-resolution spectra corresponding to the Fe2p, C1s, and S2p regions of the composites confirmed chemical interactions at the interface of the nanosized magnetite-filled composites. Fe-C and Fe-S bonds were identified in those regions between the fillers and the NBR matrix. No chemical bonds were found at the interface of the composites filled with microsized magnetite.