Synthesis and Characterization of a Superabsorbent Polymer Gel Using a Simultaneous Irradiation Technique on Corn Straw

Utilizing gamma rays as an initiating agent, a simultaneous irradiation method was applied to graft acrylic acid and acrylamide onto corn straw that had been decrystallized using a NaOH/urea solution at a reduced temperature, aiming to fabricate superabsorbent polymer gel (SAPG) capable of absorbing significantly more water. The structural attributes of the corn straw, the decrystallized corn straw, and the SAPG were analyzed via Fourier transform infrared spectroscopy (FTIR), X-ray crystal powder diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM). To enhance the SAPG's performance, optimization of various parameters was carried out, such as irradiation dose, dose rate, the ratio of monomer to corn straw, the proportion of acrylic acid (AA) to acrylamide (Am), and the degree of neutralization. The resulting SAPG exhibited distilled water absorption of 1033 g/g and 90 g/g in 0.9 wt.% NaCl solution, with a radiation dose of 5 kGy, a dose rate of 1.5 kGy/h, AA-to-AM mass ratio of 1.2, monomer-to-CS mass ratio of 7, and 90% AA neutralization.