Measurement of reversible rate of conservation materials based on gel cleaning approach

In this work, a new hydrogel designed for water-sensitive artifacts especially for China Dunhuang mural was synthesized to remove the ineffective conservation materials on mural surface. The reversible rate of each conservation material was measured based on hydrogel cleaning. It was found that the gel filled with cleaning agents showed excellent performance over the empty gel. Besides, it was more environment-friendly without mechanical damage to the sensitive surface and easier to control the cleaning process compared with pure organic solvent cleaning. 3D microscopic system confirmed the cleaning effects both visually and quantitatively. The best “conservation material-cleaning agent” pairs and their reversible rates were obtained, which were “ParaloidB72---P-xylene   +   ethyl acetate---80%”, “polyvinyl acetate---P-xylene   +   ethyl acetate---40%”, “acrylic---P-xylene---44%”, “silicone---P-xylene   +   1-Pentanol---55%”. It was also found that the reversible rates of the conservation materials declined after aging.