RADIATION INDUCED ACRYLAMIDE/CITRIC ACID HYDROGELS AND THEIR SWELLING BEHAVIORS

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.

Keywords:

• Acrylamide
• Citric acid
• Hydrogel
• Gamma radiation
• Swelling
• Polymer

ACKNOWLEDGMENT

The authors gratefully acknowledge the support of the Polymer Group in the Department of Chemistry, Hacettepe University.