Controlling the size of silica nanoparticles in filler nanomatrix structure of natural rubber

In the present work, size of silica nanoparticles in filler nanomatrix structure was controlled by graft-copolymerization of vinyltriethoxysilane (VTES) onto depmteinized natural rubber (NR) after NR was grafted with styrene to prepare NR-g-Sty-g-VTES. The structure of NR-g-Sty-g-VTES was characterized by FT-IR and NMR spectroscopy. It was demonstrated that the silica nanoparticles and polystyrene (PS) were successfully formed in natural rubber. The morphology of silica nanoparticle in the samples were observed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was observed that very small silica nanoparticles, about 60 nm, were generated in NR-g-Sty-g-VTES. The tensile strength of NR-g-Sty-g-VTES was found increasing 7 times, that is from 3 MPa for NR to 20 MPa for NR-g-Sty-VTES. Storage modulus and loss modulus for NR-g-Sty-g-VTES were found remarkably increasing 20 and 25 times as those for NR, respectively. The formation of well-controlled silica nanoparticle in the nanomatrix was proved to bring about the superior properties for NR material.