Preparation of hydrogels with self-reinforced mechanical properties using ball-milled microcrystalline cellulose and regenerated cellulose from deep eutectic solvent

Abstract

Cellulose hydrogels are green, renewable, biocompatible, and biodegradable, with promising applications in biomedicine, environmental treatment, and food packaging. However, cellulose hydrogels usually exhibit inferior mechanical properties, which limit their applications. In this study, a green and self-reinforced cellulose hydrogel with improved mechanical properties was successfully prepared by mixing regenerated cellulose (RC), which was prepared from choline chloride/DL-lactic acid deep eutectic solvent, and ball-milled microcrystalline cellulose (BMCC). Results show that the crystallinity and molecular weight of RC are significantly reduced, and it presents a round spherical or flaky shape. Especially, the hydrogels exhibit obvious and different-sized microscale pore structures, differently from the dense structure of pure BMCC hydrogels, which are favorable for improving the mechanical properties. The compressive strength of the cellulose hydrogels (55.4 kPa) increases significantly compared to pure BMCC hydrogels (40.3 kPa). In addition, the cellulose hydrogels also show excellent flexibility and thermal stability. This work provides a new idea for preparing green hydrogels with excellent mechanical properties and high-temperature stability.