Investigação do processo de fotodegradação em compostos ativos de filtros solares através das técnicas de absorção UV-VIS, FTIR e tensiometria óptica

Abstract

Solar radiation is essential for life on Earth since almost all of the biological cycles depends directly or indirectly from the ultraviolet, visible, and infrared. The need for the use of sunscreens, sunscreens also called, is an indisputable reality today. Although there are a huge variety of works related to research and development of new sunscreens, few works are dedicated to the process of photodegradation of these materials, although the effectiveness of sunscreens is guaranteed if they have a high photostability. There is also a special attention to the photochemistry of sunscreens, the possible formation of photoproducts, chemical reactions of its accumulation in human skin, can have deleterious effects. Organic sunscreens contain chromophore groups capable of absorbing light at wavelengths present in sunlight, however, can also be transformed by indirect means the presence of a photosensitizer. In this work, we aim to study the effects of UV radiation on the chemical stability of the three compounds used in commercial sunscreens. While most studies in the literature dealing with the photobleaching of solutions sunscreens, this dissertation will investigate the creams because of the techniques used is not adapted for solutions. Using the techniques of absorption UV-VIS, FTIR and optical tensiometry, we investigated the evolution of the photodegradation process of thin films of these compounds on glass slides soda-lime. Our results show that it is possible to identify how the UVA and UVB affect the chemical stability of these compounds, especially in the presence of oxygen.