Multianalytical Characterization of Acrylic Industrial Paints Used in Contemporary Mural Art

Abstract

Contemporary outdoor mural paintings have been recognized as artistic expressions closely connected with urban communities. These artworks are prone to suffer deterioration due to exposure to harsh environmental conditions. Therefore, knowledge on painting materials used by street artists is mandatory for the preservation of these paintings. In this study, for the first time, the composition of white household paints of three brands from the local market is investigated. Organic and inorganic components are identified by a multianalytical approach using scanning electron microscopy with energy-dispersive X-ray spectroscopy, thermogravimetric analysis, attenuated total reflection-Fourier transform infrared spectroscopy, and X-ray diffraction. The paints contain a styrene–acrylic copolymer and titanium white in the rutile phase as pigment. Then, two mural paintings are selected to collect samples in order to perform a stratigraphic study and characterize their materials and painting technique. In the mural “Toad on the wrong way,” the use of an acrylic resin as varnish contributes to its conservation. In the red sample of “CIDEC factory,” the identification of Pigment Red 149 (PR149) allows us to attribute the fading of the red areas to the photo-oxidation reaction of this synthetic organic pigment.