Study on superabsorbent composites. XVIII. Preparation,characterization, and property evaluation of poly(acrylic acid‐co‐acrylamide)/organomontmorillonite/sodium humate superabsorbent composites

A series of novel multifunctional poly (acrylic acid‐co‐acrylamide) (PAA‐AM)/organomontmorillonite (O‐MMT)/sodium humate (SH) superabsorbent composites were synthesized by the graft copolymerization reaction of partially neutralized acrylic acid and acrylamide on O‐MMT micropowder and SH with N,N′‐methylene bisacrylamide as a crosslinker and ammonium persulfate as an initiator in an aqueous solution. The superabsorbent composites were characterized by means of Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The effect of the relative weight ratio of SH to O‐MMT on the water absorbency was studied, and the results indicated that the best water absorbency of 591 g/g in distilled water was obtained when an O‐MMT content of 20 wt % and an SH content of 30 wt % were incorporated. The superabsorbent composite possessed a good capacity for water retention; even after 30 days, 24.4 wt % of water could still be saved by the sand soil containing 1.0 wt % superabsorbent composite. The results from this study show that the water absorbency of a superabsorbent composite is improved by the simultaneous introduction of O‐MMT and SH into a PAA‐AM network in comparison with the incorporation of only O‐MMT or SH. Also, in comparison with PAA‐AM/MMT/SH, an appropriate amount of O‐MMT can benefit the developed composites with respect to their water absorbency, salt resistance, and capacity for water retention in sand soil. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008