Preparation of Nano-Sio_2 Aqueous Suspension

Two kinds of (hydrophilic a nd hyd rophobic) na no - SiO2 a que ous suspension are obtained by several means such as high-speed mechanical stirring, sand grinding, ultrasonic wave dispersing and dispersant surface modification. The effect of type and amount of dispersant, type of wetting agent, pH value, waterborne resin and dispersing means on the dispersibility and stability of nano-SiO2 aqueous suspension are studied by means of sedimentation under room temperature, Zeta potential measurement and TEM. Nano-SiO2 aqueoussuspension with good dispersibility and stability is prepared by combination of sand grinding and ultrasonic wave dispersing, adding optimum dispersant, wetting agent and waterborne resin under the optimum pH value.