Synthesis and Characterization of Super Absorbent by Polymerization of Sodium Acrylate

A super absorbent of poly(sodium acrylate) was prepared by solution polymerisation with allyl acrylate as crosslinking agent,acrylic acid as monomer and potassium persulphate(KPS) as initiator.Parameters affecting the absorbability of the polymer were studied.When ρ(crosslinker)=0.594 g/L,ρ(KPS)=0.178 g/L,neutralization degree of monomer x(sodium acrylate)=90%,c(sodium acrylate)=4.17 mol/L,and polymerization temperature was 60 ℃,the absorbability of the polymer is up to 1360 mL/g and 162 mL/g in case of deionising water and w(NaCl)=0.9% water solution,respectively.The obtained polymer has good water absorption reversibility and the water absorbency can reach 90% of the maximum absorbability after 30 min.TGA showed the dried sample had an initial decomposition temperature of 350 ℃.XRD spectrum showed that structure of the polymer without water is orderless and when the polymer absorbed water,(it′s) main chain is spread and the structure inclines to orderliness.