Recent advancements have increasingly focused on utilizing renewable natural resources to produce nanocellulose for polymer reinforcement. Cortaderia selloana (pampas grass), a robust and widely distributed grass species known for its resilience in extreme environments, represents an abundant yet underutilized source of lignocellulosic biomass.

This study presents a novel method combining mechanical treatment with subcritical water processing to extract cellulose nanofibers (CNFs) from pampas grass. The resulting CNFs were characterized in terms of morphology, chemical composition, rheological behavior, and physical properties. These nanofibers were then incorporated into a starch-based film reinforced with chestnut shell fibers (CSFs) using a solvent casting technique as described in [2]. The film formulation was optimized using response surface methodology, evaluating the effects of the glycerol content (X1), CNFs/CSF ratio (X2), and zinc oxide (ZnO) nanoparticle content (X3) on the film’s mechanical, optical, and physicochemical properties.

The extracted CNFs measured 1–12 µm in length and 35–120 nm in diameter and demonstrated superior thermal stability (320–700 ºC) compared to commercial cellulose. FTIR analysis confirmed a high purity level, with negligible presence of lignin and hemicellulose. Incorporating just ~2% CNFs significantly enhanced the film's thermal stability and overall performance. Scanning electron microscopy (SEM) revealed a uniform microstructure with no visible phase separation between components.

In conclusion, a starch-based nanocomposite film reinforced with CNFs and CSF was successfully developed, exhibiting improved mechanical strength and water resistance. This environmentally friendly approach offers promising potential for sustainable food packaging applications.