Characterizations of interpenetrating polymer network hydrogels composed of poly(vinyl alcohol) and poly(N-isopropylacrylamide)

Abstract

Interpenetrating polymer network (IPN) hydrogels base don poly(vinyl alcohol) (PVA) and poly)N-isopropylacrylamide) (PNIPAAm) were prepared by the sequential-IPN method. The IPN hydrogels were analyzed for sorption behavior of water at 35°C and at a relative humidity of 95% using a dynamic vapor sorption system, and water diffusion coefficients were calculated. Differential scanning calorimetry was used for the quantitative determination of the amounts of freezing and non-freezing water. Free water contents in the IPN hydrogel of IPN1, IPN2 and IPN3 were 45.8, 37.9 and 33.1% in pure water, respectively.