POLYACRYLIC ACID AND POLYVINYL ALCOHOL-BASED POLYMER COMPLEXES AND HYDROGELS

In aqueous solution, in the acidic environment (pH <3), water-soluble complexes are formed based on polyacrylic acid (PAA) and polyethyleneglycol with a molecular weight of more than 6000 or on polyvinyl alcohol (PVA). The conditions for obtaining hydrogel based on polyacrylic acid and polyvinyl alcohol with a high degree of swelling (about 500 g of water/g of polymer) were determined: pH <3, temperature 120-140 degrees C. The degree of interaction of polymers is directly proportional to the content of polyvinyl alcohol in the initial mixture in the range of the molar PVA and PAA ratios from 1 : 1 to 10 : 1, the temperature and duration of heat treatment and is inversely proportional to the molecular weight of polyacrylic acid. The equilibrium degree of hydrogel swelling increases at the pH of the swelling medium above 6, and the swelling rate depends on the solvent diffusion into the hydrogel and is determined by the size of its particles and the swelling conditions (washing, mixing, etc.).