DEVELOPMENT OF THE RUSSIAN PRODUCTION TECHNOLOGY OF HIGH CLEARANCE GEL-LIKE AQUATIC POLYACRYLIC ACID (PAA)

Abstract

Guided by theoretical ideas about the laws of radical chain polymerization processes, work was carried out to study the influence of the parameters and conditions of aquatic polymerization of acrylic acid on the suitability of its polymer for therapeutic dentistry. These studies served as the basis for the development and patenting of the domestic technology for the production of a ~ 40 % aquatic gel-like solution of PAA, which is widely used both in Russia and abroad for the production of dental filling composites, and thus successfully solved the issue of import substitution and avoided various manipulation sanctions. The patented domestic technology for the production of a 40 % gel-like preparation of polyacrylic acid consists of 3 stages. 1. Dissolving 1.5 kg of maleic anhydride and 0.6 kg of initiator α,α'-azoisobutyronitrile in 32.5 kg of freshly distilled acrylic acid. 2. Tide polymerization of the prepared mixture in 120 liters of solvent water at a temperature of 93-98 ℃ for 4.5– 5 hours. 3. Concentration of the resulting ~20 % PAA solution under vacuum (residual pressure 0.8–0.015 MPa), at a temperature 65-90 ℃ to obtain a standard 40 % commercial preparation of polyacrylic acid.