Synthesis and Characterization of a Self-Assembling Hydrogel from Water-Soluble Cellulose Derivatives and Sodium Hydroxide/Thiourea Solution

Abstract

Hydrogels are hydrophilic polymers that can swell and absorb water without dissolving, provided that chemical or physical crosslinks exist among the macromolecular chains. The hydrogel can be derived from synthetic and natural polymers, the latter having desirable properties such as biocompatibility and biodegradation that do not produce adverse and reproductive and developmental effects. The aim of this study was to synthesize a physical hydrogel from a water-soluble cellulose derivative and a solution of 6 wt% sodium hydroxide/5 wt% thiourea. Physical hydrogels (also called self-assembling hydrogels) are formed when macromolecules self-assemble through non-covalent, secondary molecular interactions such as hydrophobic, electrostatic, and H-bonding. Hydroxyethyl cellulose, hydroxypropyl cellulose, and microcrystalline cellulose were used in this study. A hydrogel made from hydroxyethyl cellulose containing weight percentages of 5, 7.5, 10, and 12.5 wt% in the sodium hydroxide/thiourea solution. Hydroxypropyl cellulose only formed a cloudy yellow solution while microcrystalline cellulose did not dissolve at all in the solution. The hydroxyethyl cellulose/ sodium hydroxide/thiourea hydrogels were then characterized according to its functional groups present, physical structure, and mechanical properties, and biocompatibility.