Preparation of bamboo lignocellulose-based hydrogels dissolved in NaOH

Hydrogels are three-dimensional networks of hydrophilic polymers capable of absorbing and retaining large amounts of water. Cellulose-based hydrogels have attracted considerable attention owing to their biodegradability and non-toxicity. However, their synthesis is often constrained by the poor solubility of cellulose in common solvents. In this study, bamboo-derived lignocellulose (lignin content: 4–20%) obtained via organosolv pulping was dissolved in a 7% NaOH aqueous solution, providing a cost-effective and environmentally friendly alternative to conventional cellulose dissolution systems. The dissolution yield of lignocellulose ranged from 68% to 81%, depending on the lignin content. The hydrogels were prepared by crosslinking the dissolved lignocellulose with epichlorohydrin, and the effects of lignin content on their structural and physical properties were investigated. Hydrogels with higher lignin content exhibited greater flexibility and thermal stability while maintaining a high swelling ratio of up to 6256% after 24 h in water. These results indicate that bamboo-based organosolv pulp can be efficiently processed in an aqueous NaOH system to produce lignocellulose hydrogels with excellent water absorption performance and environmental compatibility. • Bamboo lignocellulose derived from organosolv pulping was dissolved in a 7% NaOH aqueous solution. • The dissolution efficiency ranged from 68% to 81%, depending on the lignin content. • The dissolved lignocellulose was cross-linked with epichlorohydrin to produce a hydrogel. • Higher lignin content enhanced the hydrogel's flexibility and thermal stability. • The bamboo lignocellulose-based hydrogel exhibited excellent water absorption, achieving a maximum swelling ratio of 6256%.