Synthesis of Superabsorbent Polymers Based on Sulfated Starch and Study of Their Water Absorption Properties

Abstract This study aims to synthesize and characterize a sulfated‐starch‐based superabsorbent polymer (S‐SAP). The S‐SAP is prepared by grafting 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) and acrylic acid (AA) onto sulfated starch, which is subsequently crosslinked using N , N ‐methylene‐bis‐acrylamide (MBA) via free radical polymerization with ammonium persulfate as the initiator. The successful grafting of AA and AMPS onto the starch backbone improves the thermal stability and increases the swelling capacity of the polymer. The swelling capacity and reusability of the S‐SAP are compared with those of commercial superabsorbent polymers (C‐SAPs). The swelling capacity of the S‐SAP is higher than those of C‐SAPs, reaching 417 g g −1 in distilled water and 47 g g −1 in a 0.15 M NaCl solution. The water absorption kinetics of the S‐SAP shows a good fit with the pseudo‐second‐order model. The polymer prepared herein has potential applications in horticulture and agriculture.