Thermal phase transition of poly(N-propionylethyleneimine) hydrogel

This article presents the preparation of the hydrogel of poly(N-propionylet hyleneimine) and its interpenetrating polymer network (IPN) hydrogel contai ning polyacrylamide by means of gamma-ray radiation and a study of the phas e transition temperature of these hydrogels. As a result, the hydrogel of t he crosslinked poly(N-propionylethyleneimine) exhibited swelling below and shrinking above the phase transition temperature (about 61 degrees C), as w ell as the lower critical solution temperature (LCST) of the liner polymer- water system. The experiment also showed that the LCST of the IPN hydrogel could be adjusted by the incorporation of the second component polyacrylami de. (C) 1999 John Wiley & Sons, Inc.