CRYOTROPIC GELATION OF POLY(VINYL ALCOHOL) SOLUTIONS

Poly(vinyl alcohol) cryogels are macroporous heterophase polymeric gel s, which are formed as a result of the freezing-thawing treatment of c oncentrated solutions of the polymer. These gel materials are of great interest for biotechnology, medicine, food industry, etc. The problem s associated with the mechanisms of the cryotropic gelation of poly(vi nyl alcohol) are considered in this review article, as well as the inf luence of the polymer characteristics and the conditions of cryogenic treatment on the structure and physicochemical properties of the cryog els prepared are discussed. In addition, the peculiarities of the free zing of poly(vinyl alcohol) concentrated solutions and the results of the studies of the cryocracking possibilities are described. The effec ts of the presence of soluble additives possessing different lyotropic qualities on the course of such a gelation in frozen systems are revi ewed.