Studies On Properties Of Anti-salt Poly(Acrylate-acid) Coplymer Superabsorbent Prepared By Inverse Suspension Polymerization

Poly (acrylate-co-acrylamide) (PAAAM) is prepared from partly neutralized acrylic acid (AA) and acrylamide (AM) by inverse suspension polymerization. The influence of some factors on its absorbency such as mol ratio and neutralization of monomer, concentration of crosslinker and initiator and initial temperature is discussed in detail. The results have shown that the maximum absorbency of PAAAM in distilled water and in 0.9% NaCl aqueous solution is 1300g/g and 93g/g, respectively.The effects of various salt solutions on the swelling properties are studied systemically. The results have shown that the hydration of ion is the primary affecting factor for the absorbency of the PAAAM among univalent salt solutions under the same concentration. Moreover, the complexation of cation with anionic groups of hydrogel becomes a dominant factor for multivalent cationic salt solutions, except the causes of hydration of ion. However, because a majority of the multivalent anions are complex group, the hydrolysis of the anionic groups exerts an important influence on the absorbency for anionic salt solutions.The adsorption properties of PAAAM in CuCl2, NiCl2, CoCl2 solutions are investigated and the factors that influence the adsorption such as pH value and the concentration of heavy metal ion are discussed. The maximal adsorption capacity of Cu2+,Ni2+ and Co2+ onto PAAAM are 166.4,113.5 and 101.8mg/g, respectively. It is found that PAAAM resin has the high selectivity to Cu2+ compared to the other metal ions used in this study.To acquire better performance superabsorbent, four factors affecting the performance of superabsorbent are selected to the proceed U12(6×24) uniform design in the copolymerization of acrylic acid and 2-acrylamido-2-methyl propane sulfonic acid. The optimization factors are determined to be: monomer Mol ratio: AMPS:(AA+AMPS)=0.08, neutralization of monomer: 75%, amount of crosslinker and initiator : 0.035% and 0.16% of total monomers, respectively. The results have shown that superabsorbent synthesized under optimize terms can absorb distilled water as such as 1600 g/g and 0.9%NaCl solution 130g/g.The absorption properties in salt solutions and the adsorption properties in heavy metal ion solutions of poly(acrylic acid–co-2-acrylamido-2-methyl propane sulfonic acid) (PAAAMPS) are investigated compared to those of PAAAM. The result has...