ABSTRACT - 591708 The disclosure relates to a cryogel-forming vinyl alcohol co-polymer operable to form a cryoge1 in an aqueous solution at a concentration of less than about 10% by weight, in the absence of a chemical cross-linking agent and in the absence of an emulsifier, wherein the vinyl alcohol co-polymer comprises a saponified product of a vinyl acetate co-polymer formed from at least about 80% by weight of vinyl acetate monomer, and at least about 3 % by weight of acrylamide monomer or a mixture of acrylamide monomer and acrylic acid monomer, wherein the saponified product has a degree of saponification of at least about 90%. Also disclosed is a method of forming vinyl acetate co-polymer, comprising copolymerizing at least about 80% by weight of vinyl acetate monomer, and at least about 3% by weight of acrylamide monomer or a mixture of acrylamide monomer and acrylic acid monomer, based on the weight of the monomers, in an aqueous medium with a polymerization initiator and a buffer, wherein the aqueous medium is free of emulsifier. Further disclosed is a method of forming a vinyl alcohol co-polymer cryoge1, comprising freezing an aqueous solution of said vinyl alcohol co-polymer at a temperature of from 0°C to about -196°C to form a molded mass, and thawing the molded mass to form a hydrogel.
