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

Abstract

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. Copyright © 2014 Wiley Periodicals, Inc.