Effect of monomer content and external stimuli on properties of renewable Tulipalin A-based superabsorbent hydrogels

Abstract

Series of superabsorbent hydrogels derived from renewable α-methylene-γ-butyrolactone (MBL), known as a Tulipalin A, was prepared and examined with respect on their swelling properties and stimuli responsive character. Hydrogels were synthesized by copolymerization of either sodium or potassium 4-hydroxy-2-methylenebutanoate, products resulted from saponification of MBL, with acrylamide in the presence of N,N′-methylenebis(acrylamide) as cross-linker. Hydrogels with various comonomers composition, feed monomers content and variable cross-linking density represent materials with highly tunable characteristics. The effect of temperature, pH and ionic strength of solutions on swelling behavior of the hydrogels was examined. Reversible swelling character of hydrogels in buffer and water was proved as well. Experiments demonstrated reversible ability of hydrogels to swell upon immersing to ultrapure water and deswell in buffer solution. © 2019 Elsevier Ltd