Superabsorbent composite. XIII. Effects of Al3+‐attapulgite on hydrogel strength and swelling behaviors of poly(acrylic acid)/Al3+‐attapulgite superabsorbent composites

Abstract

AbstractAl3+‐attapulgite (Al3+‐APT) was prepared by treating attapulgite (APT) with AlCl3 aqueous solution of various concentrations. The poly(acrylic acid)/Al3+‐attapulgite (PAA/Al3+‐APT) superabsorbent composite was prepared by reaction of partly neutralized acrylic acid, and Al3+‐APT in aqueous solution using N, N′‐methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The surface morphology of the composite was investigated by SEM, and the Al3+‐APT composite generated a relatively planar surface comparing the nature APT. The effects of Al3+‐APT on hydrogel strength and swelling behaviors, such as equilibrium water absorbency, swelling rate, and reswelling capability, of the superabsorbent composites were also studied. The hydrogel strength and reswelling capability were improved, however, the equilibrium water absorbency and swelling rate decreased with increasing AlCl3 solution concentration. The equilibrium water absorbency firstly increased, and then decreased with increasing Al3+‐APT content. The results indicate that Al3+‐APT acts as an assistant crosslinker in the polymeric network, which has great influences on hydrogel strength and swelling behaviors of the PAA/Al3+‐APT superabsorbent composites. POLYM. ENG. SCI., 47:619–624, 2007. © 2007 Society of Plastics Engineers.