Study on superabsorbent composite XXV. Synthesis, characterization and swelling behaviors of poly(acrylic acid-co-N-acryloylmorpholine)/attapulgite superabsorbent composites

In this work, a novel poly(acrylic acid-co-N-acryloylmorpholine)/attapulgite superabsorbent composite was prepared by graft copolymerization among acrylic acid, N-acryloylmorpholine and attapulgite in aqueous solution, using N,N0-methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The result from FTIR spectra showed that OH of attapulgite participated in graft copolymerization with acrylic acid and N-acryloylmorpholine. Proper monomer ratio and atapulgite content could form a loose surface, and improve reswelling ability and initial swelling rate. The buffer action of the COOH and COO2 groups in the superabsorbent composite keeps the water absorbency a rough constant in the pH range of 4.4–9.6. Both polarity and structure of an organic solvent are responsible for the phase transition point of the superabsorbent composite.