Superabsorbent polymeric materials IX: Effect of cationic structure on swelling behavior of crosslinked poly(sodium acrylate‐co‐cationic monomers) in aqueous salt solutions

Abstract

Two series of xerogels based on sodium acrylate (SA), trimethyl methacrylamidopropyl ammonium iodide (TMMAAI), trimethyl methacryloyloxyethyl ammonium iodide (TMMAI), and N,NЈ-methylene-bis-acrylamide (NMBA) as a crosslinker were prepared by inverse suspension polymerization. The water absorbency and swelling kinetic behavior for these xerogels in water or various saline solutions were investigated. The results showed that the swelling behaviors of these absorbents are related to their chemical structures, their compositions, and the type of external salt solutions. There would be effective improvement in the water absorbency of these two gel series by copolymerizing SA with a small amount of cationic monomer (TMMAAI or TMMAI). The initial absorption rates in deionized water were found to be faster for TM series gels than for TA series gels. The two series of superabsorbents had a tendency to absorb water in dilute nitrate aqueous solutions in the order: Fe 3ϩ , Ni 2ϩ , Ca 2ϩ , Cu 2ϩ , and Na ϩ for Fe(NO 3 ) 3 , Ni(NO 3 ) 2 , Ca(NO 3 ) 2 , Cu(NO 3 ) 2 , and NaNO 3 aqueous solution, respectively. The absorbency and initial absorption rate for these gels were related to the gel compositions and salt concentrations.

Swelling and antibacterial properties for the superabsorbent hydrogels containing silver nanoparticles

“…Tea bag method [5][6][7]11 The tea bag was made of 250 mesh nylon screen. The tea bag containing the dried sample (50 mg) was immersed in an excess of deionized water for 1 day to reach the swelling equilibrium at room temperature, and then hung up for 30 min to drain the excess solution and weighed.…”

“…2,3 The superabsorbent polymeric materials were reported in our previous reports. [4][5][6][7][8][9][10] The monomer used was acrylic acid (AA) with degree of neutralization around 90%.…”

Preparation and properties of a salt‐resistant superabsorbent polymer

“…When the salt-resistant superabsorbent swelled in physiological saline solution, AlO 2 Ϫ interacted with H 2 PO 4 Ϫ and produced Al(OH) 3 according to the following two reactions (a, b). From the reactions, we could see that the smaller the amount of NaAlO 2 was, the less Al(OH) 3 was produced, and the salt resistance of the superabsorbent decreased, while n NaAlO 2 /n KH 2 PO 4 Ͻ 0.67. The excessive NaAlO 2 interacted with H 2 PO 4 Ϫ yielded to the ion pair, which formed an electric double layer, and the electric double layer kept the colloidal particles relatively stable when n NaAlO 2 /n KH 2 PO 4 ϭ 0.67.…”

Swelling behaviors of a three‐component copolymer (starch graft sodium acrylate and 2‐acrylamido‐2‐methyl‐propanosulfonic acid) synthesized by microwave polymerization

“…1,2 With various traditional polymerization methods, including solution polymerization, 3 inverse suspension polymerization, 4 and inverse emulsion polymerization, 5 the synthesis of SAPs has been studied for several decades. However, these traditional methods for synthesizing SAPs have many disadvantages, such as longer reaction times and complicated procedures.…”