Study on the Irradiation Modification of Reed Straw and the Preparation of Highly Absorbent Gels by Graft Copolymerization

The goal of synthesizing more environmentally friendly high-water-absorbing gels (HWAGs) is to reduce the consumption of petroleum resources. We also aimed to make rational use of plant straw. Reed straw (RS) was modified using strong irradiation. Acrylamide (AM) and acrylic acid (AA) were grafted onto the cellulose for graft copolymerization reactions. The cellulose and gels were analyzed using infrared spectroscopy (IR), scanning electron microscopy (SEM), and thermogravimetric (TG) analysis. To reduce the crystallinity of the RS, the optimal irradiation dosage is 96 kGy. Single-factor and orthogonal experiments were conducted to determine the optimal reaction conditions for IRSC-HWAG: the monomer ratio m(AA):m(AM) was 1.5; The material ratio of (m(AA+Am):m(IRSC)) was 9:1; The neutralization degree of AA was approximately 90%; The irradiation dose was 5 kGy, with a dose rate of 2.0 kGy/h; the crosslinking agent dosage was 1.2%. The absorption rate of deionized water (Qd) by the gels was approximately 1160 g/g; the absorption rate of salt water (Qs) by the gels was approximately 99 g/g. A water-retention experiment demonstrated the IRSC-HWAG’s superior water-retention properties. These properties were compared with those of resins synthesized using pure chemical reagents. This experiment provides valuable reference data for the further development of plant-based water-retention agents.