Synthesis and properties of a superabsorbent from an ultraviolet‐irradiated waste nameko mushroom substrate and poly(acrylic acid)

To better use the waste nameko mushroom substrate (WNMS) and prevent its pollution into the environment, a novel superabsorbent polymer was synthesized via the UV irradiation copolymerization of acrylic acid and WNMS in the presence of an initiator (dimethoxy‐2‐phenylacetophenone and ammonium persulfate) and crosslinker N,N′‐methylenebisacrylamide. The factors that had an influence on the water absorbency of the superabsorbent polymer were investigated and optimized. Under the optimized conditions, WNMS–poly(acrylic acid) was obtained. Its swelling behaviors, which followed the pseudo‐second‐order swelling kinetic model, were investigated in distilled water (1701 g/g) and a 0.9 wt % NaCl solution (388 g/g). The water absorbency was 1011 g/g in a 0.1 wt % urea solution and 80% amount of urea diffused into the gels. The urea diffusion followed a Fickian diffusion mechanism. Moreover, the product showed excellent water retention capabilities under the condition of high temperature or high pressure. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40471.