STUDY OF LIGHT-RESISTANT AND HEAT-RESISTANT FILM FORMERS TO IMPROVE THE ANTI-AGING PROPERTIES OF LEATHER COVERS OF ANCIENT BOOKS OF THE MATENADARAN

Abstract

In the Matenadaran restoration department, scientific work continues on the study of the waterproof properties of film formers used as coatings for leather bindings. Nowadays, restorers also have the task of finding antioxidants that can protect polymer films from aging during their operation and long-term storage, which will also ensure the constancy of the physical, chemical and mechanical properties of medieval leather with polymer coatings.

In contrast to heat aging occurring in a mass of products(bookbindings), light aging starts with the surface. The rays of the violet and ultraviolet parts of the spectrum act most actively on the aging process. The aging of polymers in the light is a photochemical process when a polymer molecule, absorbing an energy quantum of the corresponding wavelength of light, goes into an unstable state of excitation. As a result, the polymer molecule gives off energy, turning into a chemical, and is spent on oxidation and destruction reactions.

Effective ultraviolet light deactivators are 2-hydroxybenzophenols, aliphatic and aromatic amines and others. A very determining condition for protecting the polymer coating of bindings from exposure is the solubility of the antioxidant in the film former. Sometimes light-filtering substances are introduced into the composition of the polymer coating compositions. For this purpose, we used different antioxidants: silicones, diethanolamine, etc.

It is known that the aging of polymeric materials is significantly accelerated by the action of light, heat, mechanical stress, and in the presence of oxygen. The membrane`s physico-chemical and physico-mechanical features were screened when added different levels of a substance that improves the membrane former`s anti-aging property as well as the exposure to heat and light.