Swelling Property of the Polyacrylamide Hydrogel Prepared by gamma-ray Irradiation

Polyacrylamide hydrogel has been synthesized by introducing x-radiation in the range of 0.4 to 5.0 kGy from(60)C(o), source for 10, 15, 20 & 25% aqueous acrylamide monomer solutions. The influences of concentration, dose, time and pH on swelling property of prepared hydrogel has been investigated. The degree of swelling is observed to be higher in case of lower concentrations and doses than higher ones. The rate of degree of swelling decreases with the increase of dose upto 1 kGy then it remains almost constant. The swelling increase rapidly with time for first 48 h then slowly to 96 h and becomes nearly constant from that time. The influence of monomer content in hydrogel sample on the swelling property, diffusional behaviour of water and diffusion coefficient have also been studied. The swelling enhances with the rise of pH due to the change of ionic content of the solvent. Maximum degree of swelling is found at neutral pH. Water desorption of hydrogel occurs within 48 h for 10 to 15% monomer concentrations, within 72 h for 20 to 25% monomer concentrations and then becomes stable. Initially, increase of desorption is so rapid and it seems that water has no affinity to gel.