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.