Preparation and performance study of AEEA/SA porous salt-resistant superabsorbent polymer

Increased osmotic pressure was achieved by ligand chelation using N-(2-hydroxyethylenediamine) (AEEA) as a ligand chelating agent and NaHCO3 as a pore-forming agent, establishing a gradient of ion concentration inside and outside the superabsorbent polymer which improved the salt resistance of a super absorbent polymer (SAP). By grafting AEEA with acrylic acid (AA) onto starch (St) and sodium alginate (SA) using an aqueous solution polymerization process, The AEEA/SA porous salt-resistant superabsorbent polymer (PASS) for enhancing the soil environment was created. Single-factor experiments were used to optimize the product preparation parameters, which were then characterized using FTIR, TGA, XRD, and SEM. When NaHCO3 and AEEA were added at 0.42 wt. % (Same as below, based on the total amount of starch and sodium alginate.) and 0.52 wt. %, respectively, PASS revealed a porous and loose network structure, indicating that they were successfully grafted onto starch and sodium alginate. The water absorption rates of PASS in distilled water, tap water, and 0.9 % NaCl solution were 682 g/g, 395 g/g, and 198 g/g, respectively, while the water absorption rates of the superabsorbent polymers (SS) without the addition of NaHCO3 and AEEA were 407 g/g, 225 g/g, and 65 g/g, respectively, and the water absorption rates were increased by 67.56 %, 75.55 %, and 205 %, so NaHCO3 and AEEA had a significant impact on the water absorption rate of salt-tolerant superabsorbent polymers.