Superabsorbent polymer of poly[acrylamide-co-(acrylic acid)] by foamed polymerization.: I.: Synthesis and water swelling properties

Superabsorbent polymers of acrylamide and acrylic acid were synthesized by foamed polymerization, initiated by ammonium persulfate and N, N, N', N'-tetramethylenediamine. The crosslinking agent N, N'-methylenebisacrylamide, the foaming agent sodium bicarbonate, and a foam stabilizer, a triblock copolymer of polyoxyethylene/polyoxypropylene/polyoxyethylene, were used in the polymerization. The superabsorbent polymer synthesized with an acrylamide/(acrylic acid) ratio of 1:9 by mole at 250 rpm and 45degreesC for 30 min of polymerization time produced the highest water absorption of 2300 times its dried weight. This article describes the synthetic method and measurements of water absorption.