Abstract

Synthesis of copolymer hydrogels from aqueous solution of acrylamide/2-hydroxyethyl methacrylate (HEMA) has been performed with radiation processing technology using Co-60 gamma source. The influence of radiation dose and concentration of HEMA on gel content, swelling properties and thermal stability of copolymer hydrogel has been investigated. Gel content of prepared hydrogel obtained maximum at the radiation dose of 30 kGy. Swelling ratio and equilibrium water content decrease with increased radiation dose and concentration of HEMA in feed solution. The water absorption of hydrogel increases with increased standing time in swelling medium. It is fast up to 24 h and then it becomes slow. The water absorption also decreases with increased concentration of HEMA in the feed solution. The water absorption of copolymer hydrogel obtained at 30 kGy radiation dose decreases from 1800 to 1400% for the increment of HEMA content from 1 to 3%. This type of diffusion of prepared hydrogel is found to be a non Fickian diffusion. The thermal stability of copolymer hydrogel prepared at the radiation dose of 30 kGy increases with increased amount of HEMA in the feed solution.

Key words: Radiation, copolymer, swelling behaviors, acrylamide/2-hydroxyethyl methacrylate.