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Resumo Neste estudo foram avaliadas as interacoes entre tres representantes minerais constituintes das rochas ornamentais graniticas (quartzo, microclina e muscovita) e tres protetivos comerciais com propriedades hidrorrepelentes. Os minerais foram caracterizados quimica e mineralogicamente por analises de fluorescencia e difracao de Raios-X (FRX e DRX, respectivamente), enquanto os protetivos foram caracterizados por meio de espectroscopia de infravermelho com transformada de Fourier (FTIR). Para avaliacao da eficacia dos protetivos, foram realizados estudos de mobilidade eletroforetica a partir da avaliacao do potencial zeta dos minerais em funcao do pH, antes e apos tratamento com cada produto. Os resultados indicaram melhor desempenho do protetivo a base de siloxano, reduzindo a eletronegatividade da superficie de todos os minerais, principalmente na faixa levemente acida de pH entre 3 e 6, onde ocorrem os principais intemperismos capazes de alterar as propriedades fisico-quimicas de rochas expostas em centros urbanos. Foram visualizadas reducoes medias de ate 15mV para quartzo, 5 mV para muscovita e 20 mV para microclina. Analises previas das rochas de um monumento e dos protetivos inicialmente elegidos para protecao sao importantes para a correta conservacao e restauro dos bens petreos que resguardam seus valores artisticos e culturais. Palavras Chave: conservacao e restauro, potencial zeta, mineral Abstract SURFACE CHEMISTRY STUDY FOR THE SELECTION OF HYDRORPEPEAL PROTEINS AND TECHNOLOGICAL SUPPORT FOR CONSERVATION AND RESTORATION OF STONE ASSETS. Interactions between the main minerals that compose the granitic dimension stones (quartz, microcline and muscovite) and three commercial hydrophobic protective coatings were investigated in this study. The minerals were characterized chemically and mineralogically through fluorescence X-ray analysis (XRF) and X-ray diffraction (XRD) respectively, while the protective coatings were characterized by Fourier transform infrared spectroscopy (FTIR). The interactions between minerals and protective coatings were evaluated by zeta potential measurements of the minerals as a function of pH before and after surface treatment with each product. The results showed that only one protective coating was able to reduce the electronegativity in all mineral samples, especially in mildly acidic pH range, where several outdoor weathering effects occur, modifying the physical and chemical properties of stone-built monuments in urban environment. Previous analysis of the stones that constitute the monument as well as preselected products for its treatment are considered important to guide the proper conservation and restoration of stone-built cultural heritages that enshrine their artistic and historical values. Keywords: conservation & restoration, zeta potential, mineral

ESTUDO DA QUÍMICA DE SUPERFÍCIE PARA SELEÇÃO DE PROTETIVOS HIDRORREPELENTES E SUPORTE TECNOLÓGICO PARA CONSERVAÇÃO E RESTAURO DE BENS PÉTREOS