Reinforcement of natural rubber with carbon black/nanoclay hybrid filler

Natural rubber (NR) based nanocomposites were prepared by incorporation of a hybrid filler system, organoclay and carbon black (CB), through melt compounding. The hybrid filler exhibited more significant reinforcing effect over the same loading of CB on NR matrix, as revealed by mechanical tests and dynamic mechanical analysis. Wide angle X-ray diffraction, transmission electron microscopy and scanning electron microscopy were used to study the microstructure of NR nanocomposites. Dynamic rheological tests were performed to elucidate the mechanism of reinforcement in order to explain the superior performance of NR containing the hybrid filler. The storage modulus G' of uncured rubber composites exhibits a three order increase in magnitude for rubber filled with 15 parts per hundred parts of rubber CB and 10 parts per hundred parts of rubber organoclay as compared with gum rubber, leading to a solid-like low frequency behaviour. The findings suggest that the reinforcement is due to a more developed filler network formation in hybrid filler system than that in single phase filler.