Enhanced Superabsorbency of Cellulose-Based Hydrogels in NaOH Solution: Synthesis, Characterization, and Performance Evaluation

Abstract

Cellulose is a natural polymer that is abundantly available in nature. This study successfully developed cellulose dissolved in NaOH and formed into hydrogels using the freeze-thaw method. NaOH solution concentration as a cellulose solvent varied from 1% (CN1) to 5% (CN5) by weight. Six cycles of freezing and thawing were performed for 20 hours at -23°C and 4 hours at 37°C. Subsequently, morphological analysis, swelling degree, weight loss, and compression testing were conducted to assess the physical properties of cellulose-based hydrogels. The results demonstrate that as the concentration of NaOH increases, the resulting hydrogel exhibits smaller pore sizes, as evidenced by optical microscope images. Additionally, the swelling degree increased with the increasing NaOH fraction. The swelling tests were performed in both distilled water and PBS solutions. Notably, soaking the hydrogels in PBS solution demonstrated their potential as superabsorbent hydrogels (SAH). Furthermore, increased NaOH fraction was associated with higher weight loss, greater Young's modulus, and reduced compressive strength.