Synthesis and characterization of super-absorbent hydrogels based on hemicellulose

A kind of novel hemicellulose-based hydrogel with excellent water absorbency was synthesized by the graft copolymerization of acrylic acid (AA), acrylic amide (AM) with hemicellulose. The various factors that influenced the water absorbency of the modified hemicellulose were studied, including AA content, hemicellulose content, neutralization degree of AA, and weight ratio (to monomer) of cross-linker and initiator. The optimal conditions were found as follows: m(AA) : m(AM) : m(hemicellulose)=15 : 3.5 : 1, the neutralization degree of AA was 75%, and weight ratio (to monomers) of the cross-linker and the initiator was 0.03% and 1.0%, respectively. The maximum absorbencies toward distilled water and 0.9 wt % NaCl solution were 1128 g/g and 132 g/g, respectively. The characteristics of the hydrogels were also investigated by Fourier Transform InfraRed (FT-IR), scanning electron microscope (SEM), and atomic force microscope (AFM). The results indicated that the undulant surface and broad network structure offer the hydrogels excellent water absorbency. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42441.