The effect of swelling time on rheological properties of hydrogels, consisting of high-amylose carboxymethyl corn starch and acrylic polymers

摘要

This paper discusses the results of studies on the preparation of hydrogels with superabsorbent properties, prepared from high-amylose carboxymethylated corn starch, which was obtained by graft copolymerization, in an aqueous environment, of acrylamide and sodium acrylate mixture on to starch, using potassium persulfate as a free radical initiator and N,N'-methylenebisacrylamide (MBA) as a cross-linker. Series of hydrogels with varying molar ratio of crosslinker to monomers were synthesized. The swelling behavior of they hydrogels was studied and the swelling properties were estimated using the kinetic equation. Rheological measurements were also performed, and continuous Maxwell model was applied to describe the viscoelastic properties. The results indicate that both G' and G '' moduli were dependent on the conditions of the reaction (ratio of cross-linker to monomer) and practically independent of the water absorption time. During the swelling process, the hydrogels exhibit high water absorption value sand novel rheological properties.