Evaluation of the Effect of Cellulose Nanofibers in Thermoplastic Starch Films

Thermoplastic starches (TPS) are important bio-based, biodegradable polymers used in flexible packaging. However, their mechanical properties, processability, and high hydrophilicity limit their applications. This study examines the effects of chemical modifications and mechanical reinforcements on TPS matrices. Combinations of native and acetylated TPS, reinforced with native (CNF) and acetylated cellulose nanofibers (CNFA) at 1%, 2%, 3%, and 10%, were analyzed. TPS films were prepared with CNF using compression molding, followed by structural, morphological, mechanical, and hygroscopic analyses. Results show that higher CNF percentages increase tensile strength, slightly reduce moisture absorption, and decrease surface hydrophilicity. High material compatibility was observed, with proper phase interaction and mechanical homogeneity, especially at the highest fiber addition level. Further evaluation with higher acetylation degrees is needed to clarify the effects of this modification.