Preparation Of SiO₂/TiO₂ Compounder Micro-spheres For Application In Cosmetic

In this work, Tetraethoxysilane (TEOS) and Titanium n-butoxide (TBOT) as raw materials were used to prepare compounded micro-spheres consisting of micrometer -sized silicon dioxide wrapped nanometer-sized titanium dioxide by the facile sol-gel method. The composite particles were modified with organosiloxane to yield the strong polarity nanometer-sized TiO2, witch agglomerate easily in the un-polarity solutions.Various experimental techniques such as Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) were applied to characterize properties of composite particles. The analysis of FT-IR and XRD are applied to examine the amount of loaded TiO2 after wrapping SiO2. The SEM is used to observe the images and forms of compounded particles and a UV-vis spectrum is used to investigate the optical features of composite grains.Optimum conditions were drawn out for the preparation of the composite particles by investigating the effect of the SiO2 solution ageing time, the ratio of SiO2 to CH3CH2OH, H2O to TBOT, Si to Ti, pH values, calcination temperatures and so on. Orthogonal experiments were applied to determine factors of granularity diameter and to choice optimum reaction conditions. The results showed that the main diameter of the composite particles is 15 to 25μm by controlling the different reaction condition and the structure of SiO2 as core and TiO2 as shell. The treatment of the surface of the composite particles can be overcome remarkably the condensation, and enhanced the stability of the dispersed systems. The analysis of FT-IR indicates that some graft polymers exist at the SiO2/TiO2 composite particles. The surface properties of modified composite particles were studied by dispersibility and penetration. The results showed that modification could improve both the hydrophobe and dispersion properties of the composite particles. The result of UV-vis absorption spectroscopy indicates the composite particles absorbed ultraviolet radiation strongly, and the photocatalysis experiment reveals that the photocatalysis of the modified particles decrease enormously. The dispersibility of TiO2 nano-particles in compounded particles observably improved UV-absorbability of compounded particles by about 4 to 5 times.Additionally, introducing the composite particles into the cosmetic, we have achieved the perfect stability. We compared the ultraviolet absorption of sun block made by ourselves with OLAY natural white UV moist lotion, SIROSE vroad spectrum sunscreen milk and so on. The results display the ultraviolet absorption of self-made sun block is stronger than that of OLAY and SIROSE in the range of 250 to 450nm wavelength. Developed with inorganic chemical sunscreen, this special process effectively shields skin from the harmful influences of ultraviolet radiation. The process utilizes ultra-fine Titanium Dioxide to reflect and absorb ultraviolet radiation and safely and effectively prevent them penetrating into skin.