Synthesis, Characterization and Swelling Behaviors of Hydroxyethyl Cellulose-g-Poly(acrylic acid)/Attapulgite Superabsorbent Composite

In this work, a series of novel hydroxyethyl cellulose-g-poly(acrylic acid)/attapulgite (HEC-g-PAA/APT) superabsorbent composites were prepared through the graft polymerization of hydroxyethyl cellulose (HEC), partially neutralized acrylic acid (AA), and attapulgite (APT) in aqueous solution, and the composites were characterized by means of Fourier-transform spectroscopy, scanning electron microscopy, and transmission electron microscopy. The effects of polymerization variables including concentrations of the initiator and crosslinker and APT content on water absorbency were studied, and the swelling properties in various pH solutions as well as the swelling kinetics in various saline solutions were also systematically evaluated. Results showed that the introduction of 5 wt% APT into HEC-g-PAA polymeric network could improve both water absorbency and water absorption rate of the superabsorbent composites. In addition, the superabsorbent composites retained high water absorbency over a wide pH range of 4-10, and the swelling kinetics of the superabsorbent composites in CaCl2 and FeCl3 solutions exhibited a remarkable overshooting phenomenon. POLYM. ENG. SCI., 50:1019-1027, 2010. (C) 2010 Society of Plastics Engineers