Preparation of silica nanoparticles using silicon tetrachloride for reinforcement of PU

Abstract A facile and economic method was proposed for the preparation of silica nanoparticles by the hydrolysis of silicon tetrachloride in alkaline solution. The starting material silicon tetrachloride was inexpensive and obtained from the by-product of polysilicon industry. The effects of the type of alkaline, alkaline concentration, reaction time, surfactant and post processing on the properties of silica nanoparticles were investigated. The morphology and size of silica nanoparticles were characterized by transmission electron microscopy and scanning electron microscopy. Spherical silica nanoparticles with narrow size distribution, high specific surface area, high dibutyl phthalate (DBP)-absorption and low density were obtained at the optimal conditions. Afterwards, silica nanoparticles were dispersed in polyurethane (PU) coatings via solution blending to reinforce PU. The mechanical properties of PU films were measured using universal testing machine and sclerometer. The results showed that the mechanical properties of PU films were obviously improved with the addition of the silica nanoparticles.