Intercalation of anionic organic ultraviolet ray absorbers into layered zinc hydroxide nitrate
Ana Cristina Trindade Cursino1, José Eduardo Ferreira da Costa Gardolinski, Fernando Wypych
1CEPESQ-Research Centre of Applied Chemistry, Department of Chemistry, Federal University of Paraná, P.O. Box 19081, 81531-980 Curitiba, PR, Brazil. anacursino@quimica.ufpr.br
Abstract:
Layered zinc hydroxide nitrate (ZHN) was synthesized and nitrate ions were topotactically exchanged with three different anionic species of commercial organic ultraviolet (UV) ray absorbers: 2-mercaptobenzoic acid, 2-aminobenzoic acid, and 4-aminobenzoic acid. The exchange reactions were confirmed by X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV-Vis) spectroscopy, and thermal analysis (thermogravimetry, TGA, and differential thermal analysis, DTA). In all the anionic exchanged products, evidence of grafting of the organic species onto the inorganic matrix was obtained. In general, after intercalation/grafting, the UV absorption ability was improved in relation to the use of the parent organic material, showing that layered hydroxide salts (LHS) can be good alternative matrixes for the immobilization of organic species with UV-blocking properties in cosmetic products.
