Surface Modification of Nanosilica with an Acrylic Silane Coupling Agent: The Role of Processing on the Surface Chemistry of Particles

In order to modify the nanosilica surface from hydrophilic to hydrophobic one, and to have a better. dispersion of nanosilica in a non-polar media, nano silica surface treatment using methacryloxy propyl trimethoxy silane was performed. In this study three independent variables were explored. These factors included silane coupling agent concentration, bath pH and hydrolysis ratio. Particle analysis was performed to investigate the surface behavior of the treated nanosilica. pH of particles was determined in a mixture of water and ethanol. Apparent densities were measured using a Helium Pycnometer. FTIR Spectroscopy was used to study the surface chemistry of the treated nanosilica. Thermogravimetric analysis (TGA) and elemental analysis were employed to illustrate the quantitative amounts of grafted silane on the surface. It was revealed that pH of particles changed from 3.8 for pristine silica to 4.9 and 6.9 for the lowest and the highest grafted particles respectively. The results indicated that the silane/silica concentration had a strong effect on the grafting of silane on the silica surface. Based on the elemental analysis, carbon content of treated silica in different condition of experiments changed between 1.2.