Improved absorption performance of itaconic acid based superabsorbent hydrogel using vinyl sulfonic acid

Abstract

Superabsorbent hydrogel (SAH) is widely used in hygiene products such as diapers. For these SAHs, the centrifuge retention capacity (CRC) and absorbency under load (AUL) are particularly important. Here, we compare the absorption properties of poly(itaconic acid–co-acrylic acid) with poly(itaconic acid-ter-acrylic acid-ter-vinyl sulfonic acid). PEGDA (Poly(ethylene glycol) diacrylate) and HDODA (1,6-hexanediol diacrylate) were used as internal crosslinking agents, and sodium persulfate as initiator. In addition, 1,4-butanediol is used as a surface crosslinking agent to improve the gel strength of SAH. The structure of the synthesized SAH was confirmed by FT-IR, and the gel strength was compared by rheological analysis. SAH using vinyl sulfonic acid had a maximum increase in CRC of 11.7 g/g compared to poly (itaconic acid-co-acrylic acid) SAH. In addition, after surface cross-linking, the AUL of the SAH using vinyl sulfonic acid increased by 6.9 g/g compared to the poly(itaconic acid-co-acrylic acid) SAH.