COMPARATIVE EVALUATION OF PROPERTIES OF XEROGELS AND AEROGELS BASED ON POLYVINYL ALCOHOL AND L-LACTIDE AND Ε-CAPROLACTONE COPOLYMER

Phys.-Math.), Chief Rasearch Scientist, Institute of Organoelement Compounds RAS named after A.N. Nesmeyanov (Moscow) The difference between aеrоgels and traditional xerogels is in the method being used in removing liquid. Recently, materials dried with the help of freeze-drying have been called aerogels. Nowadays, the term "aerogels" is used to refer to the materials obtained under supercritical conditions. The dis-tinctive features of aerogels are high porosity and specific surface, low density. These materials are positioned for medical use, for example, in tissue en-gineering and as wound dressings. The properties of aerogels based on various raw materials are described in the literature: polylactides, alginates, pec-tin, starch, cellulose, isocyanates, polymethyl siloxanes and etc. The aim of this work was to compare the physical and mechanical properties of aerogels and xerogelsout of polyvinyl alcohol and L-lactide and ε-caprolactone copolymer as an example. Drying technology in supercritical CO2 leads to increasing the strength of aerogels and xerogels based on PVA and PCL, increasing their rigidity, specific surface area and, consequently, obtaining highly porous materials. It is possible to select further the concentration and molecular mass of polyvinyl alcohol as well as solvents for copolymer of L-lactide and ε-caprolactonebased polymers for the production of porous materials, but it is obvious that the supercritical drying technology leads to an increase of aerogels elasticity while maintaining sufficient strength in a moist medium, that is very important when using medical products in vivo.