Tulips: A renewable source of monomer for superabsorbent hydrogels

Abstract

A new class of superabsorbent hydrogels was synthesized by copolymerization of acrylamide with sodium 4-hydroxy-methylenebutaimate (SHMB). SHMB is obtained by saponification of a-methylene-y-butyrolactone (MBL) which is a renewable monomer from tulips. Radical polymerization of SHMB was studied for the first tin*. The extent of side products through the ring closure depended on the pH used during the polymerization. Reactivity ratios for copolymerization of SHMB with acrylamide were estimated. Prepared hydrogels with various composition were investigated for their swelling, mechanical and thermal properties, and morphology as well as cytotoxicity. The achieved degree of swelling of the hydrogels was up to 82 000% and significantly exceeds the capacity of classical superabsorbent hydrogels made of acrylamide and salts of acrylic acid. The degree of swelling as well as mechanical and thermal properties of the hydrogels could be tuned by SHMB content.