Synthesis and swelling behavior of poly (acrylic acid-acryl amide-2-acrylamido-2-methyl-propansulfonic acid) superabsorbent copolymer

Superabsorbent copolymer (SAP) based on acrylic acid, acryl amide and 2-acrylamido-2-methyl-propansulfonic acid has been prepared in an aqueous solution using potassium persulfate as initiator and N,N′-methylenebiacrylamide (NMBA) or triethyleneglycol diacrylate (TEGDA) as crsosslinker. The absorbing properties such as equilibrium water absorbency and swelling properties in different concentration of saline waters were investigated. The relationship between the properties and synthesis conditions such as the concentration and kinds of crosslinking agent, initiators and neutralization degree and monomer ratio were also investigated. The results show that the water absorbency of the SAPs reach 58 g/g at the ionic strength of 1000 mmol/L and the water absorbency decreases with the increase of the concentration of saline water.