Immobilization of TiO2 nanoparticles on montmorillonite clay and its effect on the morphology of natural rubber nanocomposites

Natural rubber/organoclay/titanium dioxide nanocomposites were obtained via mechanical blending using rubber latex, organically modified montmorillonite clay (cloisite 30B) and titanium dioxide (TiO₂). Glycerol was utilized as a dispersant for the inorganic components. Scanning electron microscopy analysis shows that TiO₂ nanoparticles were deposited on the clay surface and that the clay–TiO₂ combination was homogeneously dispersed on the natural rubber. The high aspect ratio and the polar character of the clay layers allowed interactions with individual nanoparticles of TiO₂. The X-ray diffraction patterns reveal an increment of the crystalline character of the NR/C30B/TiO₂ nanocomposites as a consequence of the nanoscale dispersion of the TiO₂ particles. Infrared Spectroscopy spectra indicate compatibility between natural rubber and glycerol due to the formation of hydrogen bonds. A mechanism in particle–natural rubber compatibility, in which glycerol is involved, is proposed. However, nanoscale dispersion was largely dependent on the clay–TiO₂ interactions. This work proposes an easy method to immobilize TiO₂ nanoparticles on clay layers, which allows their dispersion in polymers. Nanocomposites obtained by this method can be used for supports of photocatalyst molecules.