Synthesis of Hydrogels by Polymerization of Itaconic Acid-Choline Chloride Deep Eutectic Solvent

Itaconic acid (IA)-choline chloride (CC) deep eutectic solvents (DES) were prepared and characterized by NMR, TGA, and DSC. Poly(itaconic acid-co-bisacrylamide) hydrogels were synthesized by in situ polymerization-crosslinking of the DES. For comparison, the hydrogels were also prepared in water under the same process conditions, that is, temperature, time, initial concentration of the monomer, the initiator, and N,N-methylenebisacrylamide (BAA) as the cross-linking agent. Chemical structure of the polymers was proved by elemental analysis and FTIR. The values of insoluble gel fraction and water swelling of obtained hydrogels suggest that polymers prepared in DES have higher cross-link density. Preliminary comparative studies of polymerization of IA in water and in DES medium indicated higher polymerization rate resulting from the presence of the choline salt, what might explain properties of the hydrogels prepared in DES. This study shows that DES can be used both as a solvent and catalyst in free-radical polymerization processes. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40608.