Synthesis and Swelling Properties of Guar Gum-g-poly(sodium acrylate)/ Na-montmorillonite Superabsorbent Nanocomposite

Abstract

Novel guar gum-g-poly(sodium acrylate)/Na-montmorillonite (GG-g-PNaA/MMT) superabsorbent nanocomposites were synthesized by grafted copolymerization among natural guar gum (GG), partially neutralized acrylic acid (NaA) and Na-montmorillonite (MMT) in the aqueous solution using ammonium persulfate as initiator and N,N′-methylenebisacrylamide (MBA) as crosslinker. Fourier transform infrared spectroscopy confirmed that NaA had been grafted onto GG and the -OH groups of MMT participated in the reaction. X-ray diffraction and scanning electron microscopy analyses revealed that MMT was exfoliated and equably dispersed in GG-g-PNaA matrix. The effects of MMT and MBA on water absorbency were investigated. The results show that introducing MMT into the GG-g-PNaA network improved the swelling capability and the swelling rate of the superabsorbent nanocomposite. The nanocomposites keep water absorbency high, within a wide pH range from 4 to 11 and exhibit better reswelling capability.