Preparation and Characterization of Nano-TiO2/poly (methyl methacrylate) Hybrid Latex by Reverse Microemulsion Method andIn-SituPolymerization

The organic nano-TiO2 was synthesized in reverse (W/O) microemulsion, using tetrabutyl titanate (TBOT) as precursor and γ-methacryloxypropyl trimethoxy silane (KH-570) as modifier. After phase inversion from W/O microemulsion to oil-in-water (O/W) emulsion, nano-TiO2/poly(methyl methacrylate) hybrid latex was prepared via in-situ polymerization based on the O/W emulsion containing organic nano-TiO2. Fourier transform infrared spectroscopy (FTIR) indicated that KH-570 was successfully grafted onto the surface of TiO2 particles. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) demonstrated that the average diameter of nano-TiO2 was about 10 nm and the hybrid latex had obvious core-shell structure with particle size of 155 nm. The TBOT content and the mass ratio of KH-570 to TOBT have important effect on the polymerization stability and storage stability of the hybrid latex. When the TBOT content was 5% and the mass ratio of KH-570 to TOBT was 0.6, the coagulation rate (Cr) was 3.0% and the zeta potential reached 36.1 mV. The possible formation mechanism of the hybrid latex was also proposed.