About the restoration of museum objects from unburned clay

The article deals with the problems of conservation of artifacts made from unbaked clay. The reasons causing the destruction of such objects are described. A brief history of the search for a suitable reinforcing composition for the preservation of loess artifacts and the result of the choice of these materials by the largest museums with such collections is given. The work carried out in the chemical-technological laboratory (The State Research Institute for Restoration) to find the optimal material for strengthening such items is outlined. Polyethylene glycol (PEG-1500) was taken as the basis of the strengthening composition, as the volume that penetrates most deeply and evenly into the loess layer. To increase the strength of PEG-1500, the processes of its modification with various polymers were carried out: methylcellulose, acrylic copolymer, and polyvinyl butyral. Fragments of painting on a loess base from the excavations of Central Asia were used as model samples. The samples were determined by the depth of impregnation, change in hardness, change in color. As a result of the work, two reinforcing compositions based on PEG-1500 were selected: with an acrylic copolymer and polyvinyl butyral. They were used for samples of varying degrees of destruction. Cases of strengthening loess volumes with and without a paint layer are considered. A technique for cleaning samples with different degrees of density has been worked out. A table is given of the penetration depth and strengthening action of the consolidant, depending on the strength of the clay base and the presence of a paint layer