A novel superabsorbent material based on soybean straw: Synthesis and characterization

A novel superabsorbent copolymer (SAP) was developed by grafting acrylic acid onto the pretreated soybean straw (PSBS) using gamma-ray irradiation. The structure of soybean straw, treated soybean straw, and SAP were characterized through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM). The effect of irradiation dose, the dosage of cross-link agent, and the monomer ratio of the graft copolymer on the water absorbency of the SAP was investigated. The highest water absorbency of 1,489 g/g in distilled water and 56 g/g in 0.9 wt% NaCl solution was obtained, when the ratio of acrylic acid (AA) to PSBS was 6:1. This irradiation technique is superior to traditional methods with advantages such as less heavy pollution, low-energy consumption, and high-water retention performance. The outcome is deemed to open up new pathways to synthesize environmentally safe superabsorbents with applications in the food, pharmaceutical, and medical industries.