The Effect of PEG on the Water Absorption Capacity and Rate of Superabsorbent Copolymers Based on Acrylic Acid

Abstract

ABSTRACT In this study, acrylic acid–based superabsorbent copolymers were synthesized with different comonomers (PEGs) by inverse suspension polymerization technique. The said superabsorbent copolymers were obtained from the aqueous solution of monomers dispersed in a continuous organic phase. The inverse suspension polymerization was accomplished by the use of aqueous solutions of partly neutralized acrylic acid with a predetermined crosslinker agent/monomer ratio in cyclohexane. Sorbitan monostearate was used as a surfactant, ethylene glycol dimethacrylate (EGDM) either as a comonomer or a crosslinking agent, potassium persulfate as the initiator, and polyethylene glycols (PEG 200, PEG 1000, PEG 4000) were used as pore-making agents. The copolymers (SAPs) were characterized by IR spectroscopy and SEM micrographs. Effect of PEGs on the water absorption capacity, rate of absorption to reach equilibrium, and the time needed to release the water absorbed from the gels were investigated. It was observed that the copolymer based on EGDM-Na acrylate + PEG4000 (A3) gave better results than the other copolyemrs. Keywords: swellingwater-soluble polymersradical polymerizationgelscrosslinking