Natural superabsorbent nanocomposite optimization to balance stability and biodegradability

Given the increasing need for new strategies to face the current drought scenario caused by climate change in agriculture, this study focuses on the development of a natural-derived superabsorbent nanocomposite (NSN) intended to potentially replace petroleum-based alternatives available on the market. We optimized a formulation containing cellulose, citric acid (CA), and nanoparticles. The resulting material was characterized by rheological and thermogravimetric analysis, and its water absorption in ionic and soil environments as well as its biodegradation potential. Our results indicated that NSN containing 3% CA and 5% nanoparticle loading showed the most favourable balance of swelling and mechanical properties among the tested formulations. Material characterization indicated that the optimized NSN showed improved thermal stability with a degradation temperature close to 300 °C and enhanced viscoelastic properties compared to the other experimental formulations. It exhibited a high swelling ratio under all tested salt solutions and a good reswelling ability over multiple cycles. Biodegradation studies revealed a slow degradation, with approximately 40% of the material remaining after 100 days. We conclude that the NSN formulation showed a favourable swelling ratio and mechanical properties in addition to slow biodegradation, indicating its potential for applications in agriculture.