Abstract: Superabsorbent resins with performance of good salt-tolerance were synthesized by inverse-suspension polymerization of acrylic acid in the presence of a crosslinking agent(N,N'-methylene bisacrylamide), an initiator (ammonium persulfate) and a chelant (ethylenediamine tetraacetic acid, EDTA). Influences of the amounts of crosslinking agent, chelant and initiator as well as degree of neutralization of acrylic acid on the absorption capacities toward water and salt solution were studied. It was found that the introduction of chelant EDTA promoted significantly absorption toward salt solution. It was also demonstrated that amounts of crosslinking agent, initiator and the degree of neutralization of acrylic acid influenced to a certain extent the absorption of resin toward 0.9% NaCl solution. Stable suspension could be obtained by using mixed non-ionic/anionic oligomers as surfactants. The resulted resins showed absorption capacities of more than 670 g/g toward water and 170 g/g toward 0.9% NaCl solution respectively.

Key words: salt-tolerance, superabsorbent resin, inverse-suspension polymerization