Synthesis and properties of a novel superabsorbent polymer composite from microwave irradiated waste material cultured Auricularia auricula and poly (acrylic acid‐co‐acrylamide)

A novel superabsorbent polymer composite was successfully synthesized from waste material cultured Auricularia auricula (WMCAA) and poly (acrylic acid‐co‐acrylamide) (P(AA‐co‐AM)) using microwave irradiation. Optimal synthesis conditions were determined by investigating the water absorbency of the superabsorbent composite. The effects associated with weight ratios of WMCAA, acrylamide (AM) monomers, initiators, and acrylic acid (AA) crosslinkers, as well as the degree of neutralization of AA were examined. The maximum water absorbencies were found to be 1548 g/g (distilled water) and 72 g/g (0.9% NaCl solution). Fourier transform infrared spectroscopy (FTIR) was applied to determine the molecular structure of the superabsorbent composite, and scanning electron microscopy (SEM) was used to demonstrate the characteristic compact and porous structure of the material. Further studies conducted via transmission electron microscopy (TEM) revealed the formation of a novel interpenetrating polymer network structure. Thermogravimetry/differential thermal (TG/DTG) analysis demonstrated improved thermal stability in the composite material compared with WMCAA. Additionally, high water absorption rates observed in the polymer during the swelling process indicated first‐order kinetics. The water absorption and adsorption of the superabsorbent composite were studied in a variety of fertilizer solutions, revealing an indirect relationship between water absorbing ability and fertilizer concentration. Conversely, a direct relationship was observed between absorbed fertilizer and fertilizer concentration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3674–3681, 2013