Synthesis and Swelling Behavior of Superabsorbents Cross-Linked with N-Maleyl Chitosan

Abstract

A kind of superabsorbent based on the monomers maleic anhydride (MA) and acrylic acid (AA) was prepared by solution polymerization using ammonium peroxodisulfate (AP) and sodium bisulfite (NaHSO3) as initiator, and N-maleyl chitosan (N-MACH) as cross-linker. Effects of process parameters such as the amount of cross-linker, mass ratio of MA to AA, and neutralization degree of AA on the water absorbency of superabsorbents are discussed. The results indicated the water absorbency of superabsorbents increased and then decreased with the increase of MA content, the amount of the N-MACH cross-linker, and the neutralization degree of AA. Under the optimal conditions, the water absorbency of superabsorbents could reach l560.42 g/g and 83.7 g/g in distilled water and in 0.9% NaCl solution, respectively. In addition, to enhance the water absorbency of superabsorbents in 0.9% NaCl solution, polyvinyl alcohol (PVA) was introduced as interpenetrating polymer in the network and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) was introduced as comonomer. It was proved that PVA and AMPS could effectively improve the water absorbency of superabsorbents both in distilled water and 0.9% NaCl solution.