After 2 hours, specified amount
of glycerol was added to the mixture and the reaction was continued for 24 hours
The
crosslinked polymers, then, were placed in distilled water. The water was replaced
regularly up to 48 hours to ensure the removal of unreacted materials. The swollen
gels were dried in a vacuum oven at 40°C to constant weight (about 24 hours), cut
into pieces, and stored in a dessiccator for subsequent experiments. The chemical
structure of the hydrogel is schematically presented in scheme 5-1.