Abstract
Citric acid (CAc) moieties containing acrylamide (AAm) hydrogels were prepared by gamma irradiation of their aqueous solutions. A possible polymerization and crosslinking mechanism for acrylamide/citric acid (AAm/CAc) hydrogels is proposed. The effects of irradiation dose and citric acid content on swelling behavior were investigated. Swelling took place in water at 25°C and was followed gravimetrically. Incorporation of a relatively low amount of citric acid to acrylamide hydrogel increased its swelling up to 950% from 700%. The diffusion of water into AAm/CAc hydrogels was found to be a non-Fickian type. Diffusion coefficients of AAm/CAc hydrogels found as 5 × 10−7− 10 × 10−7 cm2 sec−1. It has also been found that the number average molar mass between crosslinks is increased with the CAc content and decreased with irradiation dose.
ACKNOWLEDGMENT
The authors gratefully acknowledge the support of the Polymer Group in the Department of Chemistry, Hacettepe University.