Titanium dioxide/poly(methyl methacrylate) composite microspheres prepared by in situ suspension polymerization and their ability to protect against UV rays

Homogenously dispersed TiO2/poly(methyl methacrylate) (PMMA) composite microspheres were produced in the size range of 1-10 mum and the interfacial characteristics of TiO2 and PMMA in suspension polymerization were considered. In electron microscopy observation, it was found that TiO2 nanoparticles were embedded homogeneously in the PMMA phase. This study elucidates that the interfacial compatibility between TiO2 and PMMA played a decisive role in producing the composite microspheres structured with inner TiO2 and continuous PMMA, which was achieved by treating the surface of the TiO2 particles hydrophobically. The TiO2/PMMA composite microspheres produced showed good ability to protect against UV rays and are therefore of great usefulness in cosmetic formulations.