STUDY ON KINETICS AND SWELLING BEHAVIORS OF THE (n-ISOPROPYLACRYLAMIDE-co-MALEIC ACID) COPOLYMERIC HYDROGELS

Abstract

      Copolymers of N-isopropylacrylamide (NIPAM) and maleic acid (MA) were synthesised by free radical polymerization in water using N,N'-methylene bis - acrylamide (MBA) as crosslinker, using N'-tetrametyletylendiamin (TEMED)/amoni persunfat (APS) ([TEMED]/[APS]=1) as a system initiator. The reactivity ratios of the monomers were computed by Kelen-Tudos method at lower conversion. Hydrogels swelling/deswelling properties in water were investigated. The reactivity ratios obtained rNIPAM 0,45 and rMA 0.08 showed richer content of NIPAM than MA in the copolymer. In addition, swelling equilibrium ratio increased by enhancing the MA content.

Keywords: N-isopropylacrylamide (NIPAAm), maleic acid, thermoresponsive hydrogels