RADIATION INITIATED SYNTHESIS OF ACRYLIC ACID-CO-ACRYLAMIDE AS PH AND SALT SENSITIVE HYDROGEL

This paper is a report on a study which synthesized acrylic hydrogel in the presence of ultrasonic irradiation (20-kHz, power 80%, pulse 8) in a water/glycerol medium. Acrylic acid (AA) and acrylamide (AAm) were used as acrylic monomers, and methylene bisacrylamide (MBA) as the crosslinker. The experiments were performed at a constant temperature of 37°C. The swelling behaviors in various buffer solutions, temperatures and various ionic salt solutions were investigated in detail. In addition, the pH-reversibility was preliminarily investigated with alternating pH between 11 and 3. It was found that hydrogel formation is faster in the presence of ultrasound than in its absence. In addition, SEM and UV spectroscopy showed that the hydrogel synthesized ultrasonically has a higher swelling capacity and a more uniform and porous structure. It was also discovered that hydrogel formation speeds up at higher quantities of glycerol. However, an increase in crosslinker concentration proved ineffective although it changed the appearance of the hydrogel. The effect of cationic salt solutions on the swelling had the following order: Na+>Ca2+>Fe3+. The results showed that the equilibrium swelling was achieved in 20 min. The hydrogel was responsive to the pH and salts; it also has reversible swelling and deswelling character. The method proposed in this research can be used in the synthesis of biomedical materials and in the development of drug delivery systems

Keywords:

Copolymerization , Synthesis , Hydrogel , Swelling , pH-sensitive