Synergistic effect of nanobarite and carbon black fillers in natural rubber matrix

Novel rubber nanocomposites based on natural rubber (NR), nanobarite (NB) and carbon black (CB) were prepared by mechanical compounding with the aim of determining the synergistic effect of NB and CB fillers in the NR matrix. The morphology and properties of these nanocomposites were investigated. The results indicated that the reinforcement of NB was influenced by the organic treatment method. In comparison with unmodified NB (U-NB) and NB modified by sodium stearate (SA-NB), NB modified by sodium aluminate and sodium stearate (SA-Al2O3-NB) exhibited outstanding reinforcement due to its homogenous dispersion in the NR matrix and the stronger polymer–filler interactions. In order to optimize the synergistic effect of CB and SA-Al2O3-NB in the NR matrix, thorough and systematic analyses were performed on NR/CB/SA-Al2O3-NB containing various combinations of CB and SA-Al2O3-NB, which revealed that the overall properties strongly depended on the extent of the dispersion of CB and SA-Al2O3-NB fillers. Incorporating 2 wt.% SA-Al2O3-NB to the control NR containing 45 wt.% CB resulted in an obvious synergistic effect, including accelerating the curing process, improving the mechanical properties and enhancing the thermo oxidative resistance and corrosion resistance.