Inverse suspension polymerization of poly(methacrylic acid-co-partially neutralized acrylic acid) superabsorbent hydrogels: synthesis and water uptake behavior

Superabsorbent poly(methacrylic acid-co-partially neutralized acrylic acid) hydrogels have been prepared by inverse suspension polymerization, using SPAN 80 as dispersant, heptane as the organic phase, N,N'-methylene bisacrylamide as the cross-linker and potassium persulphate as initiator. The water uptake behavior has been analyzed as a function of amount of cross-linker, concentration of dispersant, stirring rate, synthesis temperature and particle size of gels. Their swelling behavior was also studied in salt solutions, Various types of diffusion coefficients and activation energy for swelling process were also evaluated.