Synthesis and Adsorption of Acrylic Acid Superabsorbent Resin by Inverse Suspension Polymerization

Two types of high water absorbing resins,poly(acrylic acid-co-acrylamide)(PAAM) and poly(acrylic acid-co-2-acrylamido-2-methyl-propane sulfonic acid)(PAAMPS)were synthesized by reverse suspension copolymerization.Their absorbencies and adsorptions are investigated in distilled water,NaCl solution and various salt solutions.In initial adsorption stage,the absorbencies in distilled water,0.9%NaCl solution and various salt solutions and the adsorption uptakes of metal ions for PAAM and PAAMPS increase fast and both reach an equilibrium values within 10 min.The absorbencies of PAAM and PAAMPS in salt solutions are clearly lower than that in distilled water,the equilibrium absorbencies of PAAMPS are greater than that of PAAM and the salt-resistant properties of PAAMPS are better than that of PAAM.When AMPS monomer is added instead of AM,the equilibrium adsorption uptakes hardly change for Cu2+ and Cr3+,but decreases slightly for Fe3+.Absorbing time of PAAM becomes longer than that of PAAMPS.