Natural Rubber Nanocomposites with Segregated and Random Network of Multiwalled Carbon Nanotube/Nanosilica Hybrid Fillers

NR-nanosilica/multiwalled carbon nanotube hybrid filler composites were prepared by two different processes. NRCSF composites prepared by the latex stage mixing of the hybrid filler dispersion followed by film casting and curing resulted in segregated hybrid filler network due to the alignment of the filler along the periphery of the rubber latex spheres on drying. Whereas the NRCSH composites prepared by co-coagulating the hybrid filler dispersion with NR latex followed by drying and mixing in an internal mixer destroyed the segregated network structure and yielded a random dispersion of fillers in the matrix. Comparison of properties of both vulcanizates revealed that incorporation of nanosilica decorated multiwalled carbon nanotubes in the natural rubber (NR) has significantly enhanced the mechanical and solvent barrier properties in both cases. However the electrical properties were highly dependent on the filler morphology inside rubber; with very good electrical properties at very low percolation threshold for the NRCSF composites due to the segregated conductive network and very poor electrical properties for the NRCSH composites due to the absence of conductive network.