Encapsulation of titanium dioxide particles by polystyrene via radical polymerization

The paper describes the preparation and characterization of a novel type of SiO2-and-Al2O3-coated-TiO2 particle encapsulated by polystyrene via radical polymerization. SiO2-and-Al2O3-coated-TiO2 particle was modified by 3-(trimethoxysilyl)propylmethacrylate (MPS) coupling agent, followed by free radical copolymerization of styrene with the methacrylate group of MPS at the particle surface. The inorganic particle/polystyrene core-shell composites were characterized by means of FTIR spectroscopy, transmission electron microscopy (TEM), elemental analysis, gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). TEM and FTIR investigation provided direct and clear evidence for the presence of polystyrene shell on SiO2-and-Al2O3-coated-TiO2 core particles, and TGA showed quantitative evidence of the presence of polystyrene shell on SiO2-and-Al2O3-coated-TiO2 core particles. It was demonstrated that polystyrene shell was chemically bonded to inorganic core surface, leading to more stable core-shell microspheres.