Sustainable Fabrication of Carboxymethyl Cellulose‐Based Hydrogels via Microwave‐Assisted Drying

ABSTRACT Superabsorbent polymers (SAPs) are cross‐linked hydrophilic materials capable of retaining large amounts of water; however, most commercial SAPs are derived from petroleum‐based acrylates. Herein, an energy‐efficient, solvent‐free strategy is presented for fabricating sustainable carboxymethyl cellulose (CMC)‐based hydrogels via epichlorohydrin crosslinking. The gelation conditions were optimized by varying catalyst concentration, temperature, and reaction time, and the optimal hydrogel was obtained using 3 wt% NaOH at 70°C for 2 h. The resulting hydrogel exhibited a high distilled‐water uptake of 289 g/g and a saline uptake of 102 g/g, surpassing commercial natural polysaccharide‐based SAPs. Compared to conventional freeze‐drying, the microwave‐assisted dehydration route reduced the carbon footprint to 3.76 kg CO 2 eq/kg, corresponding to more than 90% lower energy use and a significantly shortened drying time, while maintaining excellent mechanical and thermal stability. The proposed process bridges high functional performance with environmental compatibility, providing a viable direction for sustainable hydrogel manufacturing.