Synthesis and Characterization of Nanosilica from Rice Husk with Applications to Polymer Composites

The present study deals with preparation of Silica nanoparticles (SiO2NPs) from rice husk ash and to be used as nanofiller in Epoxy/SiO2 –nanocomposites. Pure amorphous Silica (SiO2) was prepared from rice husk ash (RHA) by thermal treatment of the rice husk at 400°C followed by acidic treatment and then thermal treatment of the ash at 650°C. The produced Silica was then characterized by X-ray fluorescence and X-ray diffraction to confirm the purity and crystalline of silica. The obtained pure amorphous Silica was used to produce Silica nanoparticles. Process parameters such as: NaOH mixing time and drying time, were studied and the particle sizes were confirmed by Atomic force microscopy (AFM). The best average particle diameters of SiO2 NPs were (53nm) using the best mixing time 14 hours of Silica particles with 2.5 N NaOH at best drying time (48 hours) of silica solution. Fourier Transformation infrared Spectroscopy (FTIR) showed that broadband appeared at about 3429.43cm -1 which represent the presence of hydroxyl groups on the SiO2 NPs surface and no further functionalization is needed. Tensile test of Epoxy - (0, 0.25, 0.5, 0.75, 1, 2, 3, 6, 9, 12 and 14 wt%) SiO2 nanocomposites results showed that the best improvements in tensile strength of epoxy resin at a loading of 0.5 wt % SiO2 NPs due to better dispersion.