Synthesis, characterization and swelling behaviors of guar gum-g-poly(sodium acrylate-co-styrene)/vermiculite superabsorbent composites

Abstract

A series of novel superabsorbent composites guar gum- g-poly(sodium acrylate- co-styrene)/vermiculite (GG- g-poly(NaA- co-St)/VMT) were prepared by the simultaneous graft copolymerization of guar gum (GG), partially neutralized acrylic acid (NaA), styrene (St) and vermiculite (VMT) using ammonium persulfate (APS) as the initiator and N,N′-methylene- bis-acrylamide (MBA) as the crosslinker. Fourier transform–infrared (FT-IR) and ultraviolet-visible (UV-vis) spectroscopy revealed that NaA and St had been grafted onto GG main-chain, and VMT participated in polymerization reaction. The simultaneous incorporation of St and VMT improved the surface pore structure, and VMT led to a better dispersion in the polymer matrix as shown by field emission scanning electron microscope (FESEM). Swelling results indicated that the inclusion of proper amount of St and VMT in the superabsorbents induced enhanced swelling capability, rate, and salt-resistant performance. Moreover, the composites showed good pH-stability in the solution of various pHs, and exhibited smart swelling–shrinking on–off swelling characteristic in physiological solution, which can be used as promising candidate for its applications in various fields.