Estudo do óleo de linhaça natural e envelhecido artificialmente em sistemas contendo óxido de zinco e dióxido de titânio

• Ano de defesa: 2009
• Autor(a) principal: Marcelo Marques da Fonseca
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Análise Térmica; Linhaça; Pigmentos; Química analítica; Reologia; Torta oleaginosa; Química; Tintas
• Link de acesso: http://hdl.handle.net/1843/SFSA-85TT7T

Natural and artificially aged films of linseed oil and paints containing zinc oxide and titanium dioxide have been studied by Thermal Analysis (TG / DTG, DTA and DSC), in Infrared Spectroscopy with Fourier Transform (FTIR) spectroscopy and the average life of Positrons (EVMP). The characterization of natural samples showed, by XRD, the presence of zinc oxide and titanium dioxide as the main pigment used in oil paints and calcium carbonate as filler common of these materials. The gas chromatography confirmed and quantified the linseed oil in the matrix and Infrared Spectroscopy with Fourier Transform of helped in identifying the constituents of the organic matrix. This technique (FTIR) demonstrates variations that happened in the organic matrix, about the systems under study, relating to the products of auto-oxidation which modifying the steric and electronic properties of the environment. The thermogravimetry (TG) in dynamic atmospheres of synthetic air and nitrogen showed that natural and aged samples are decomposed into distinct stages, identified by the DTG curves and the stages of decomposition are preceded by adsorption of gaseous oxygen and nitrogen by organic matrix. The DTA curves, obtained in dynamic atmosphere of synthetic air, the oxidation of the paint showed through clear exothermic peaks occurring in the range between 380 ° C and 500 ° C, differing from the oxidation of films of linseed oil that had several exothermic peaks in same region, which is unified with time of aging. Other techniques like DSC and EVMP and kinetic study of thermal decomposition of the samples confirmed the reticulation process and organizational structure of the matrices containing zinc oxide and titanium dioxide allows the correlation of these processes with the conductive nature of these pigments.