PVA (Mw 67000, 87-89% hydrolyzed, ～1400 polymerization) is a form of polyvinyl alcohol with a molecular weight of 67000 and hydrolytic properties. The degree of hydrolysis indicates the rate at which acetate groups in the original polyvinyl acetate are converted to hydroxyl groups. This PVA is obtained by polymerizing vinyl acetate and subsequently removing the acetate groups through hydrolysis. Polyvinyl alcohols with varying degrees of hydrolysis can be used in self-crosslinking to form freeze gels, which are utilized as biological excipients.