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Calcium hydroxide nanoparticles for deacidiﬁcation of canvas oil paintings

Oil paintings consist of several layers, cellulose is the main components of all types supports of oil painting either it was canvas, paper or wood. The deacidification of canvas oil painting was studied. Cellulose is oxidized by air and hydrolyzed by water vapor, The oxidation process creates acid groups that lower the pH of the canvas which cause the loss of canvas oil paintings mechanical properties. Nanoparticles of Ca(OH)2 can be dispersed in different solvents (e.g. short chain alcohols) and applied on canvas, to balance acidity and long-term protection. The characterization of nanoparticles was carried out by transmission electron microscopy (TEM), regular shape of particles can be seen. Scanning electron microscope (SEM) show stable fiber of cellulose. Canvas samples were artificially aged after deacidification using calcium hydroxide nanoparticles dispersed in short chain alcohols. Cellulose pyrolysis temperature and samples’ pH were evaluated after and before the artificially aging, the applied deacidification treatments raised samples pH to slightly basic values, these values remained constant upon artificial aging.