Study of the chemical composition and the mechanical behaviour of 20th century commercial artists' oil paints containing manganese-based pigments

摘要

The present study deals with 20th century manufactured artists' oil paints containing raw udand burnt umber pigments, this is, natural earth pigments resulting from the combination of iron and udmanganese oxides. Manganese, in particular, is known to be a primary drier and to have a siccative udeffect on oil paint films.udThis research aims to show the diversity of formulations behind apparently same commercial names as udwell as to understand how the content of manganese, the presence of modern lipidic media and the udhydrolysis mechanisms can promote significant differences in the expected mechanical properties of udoil paint films, thus conditioning their long-term performance. udSeveral manufactured artists' oil paint films containing manganese were selected. Dried films from udraw and burnt umber oil paints by Winsor&Newton® (UK), Grumbacher® (USA), Gamblin® (USA) and udSpeedball® (USA) were studied and information about their chemical composition and mechanical udbehaviour is here presented. In addition to the identification and the study of the inorganic and organic udcomponents present in each formulation through LM, SEM-EDX, FTIR-ATR, XRD, GC-MS analysis, udtensile tests were run and stress-strain curves were obtained. Together with evident hue differences, udthe obtained results showed significant differences in the chemical composition and the mechanical udbehaviour of the oil paint films.