Water Behavior of Poly(acrylic acid)/ Poly (acrylonitrile) Semi-Interpenetrating Polymer Network Hydrogels

Abstract

Semi-interpenetrating polymer network (semi-LPN) hydrogels, composed of poly(acrylic acid) (PAAc) and poly(acrylonitrile) (PAN), were prepared using UV irradiation. The characteristics of semi-IPN hydrogels were investigated by swelling experiments, and differential scanning calorimetry (DSC). The semi-IPN hydrogels exhibited swelling ratio in the range of 24.1-81.8% at 35°C. The swelling ratio of the semi-IPN hydrogels depended on pH and temperature. DSC was used for the quantitative determination of the amounts of free and bound water. The free water contents in the semi-IPN hydrogel AN21, AN31, and AN41 were 1.2, 2.4, and 11.3% in pure water, respectively. Activation energies of semi-IPN hydrogels also were calculated.