Abstract
Abstract. This study investigated the effects of cellulose filler, including ultrasonicated cellulose, on the morphology and intermolecular interactions of thermoplastic starch (TPS). SEM analysis has shown that pure TPS has a relatively smooth and compact surface, while TPS/cellulose composites have a coarser and more heterogeneous morphology with visible fibrillar structures, fiber elongation, and micro- and submicron-scale cellulose features. The untreated sample retained a coarse-layer structure with limited fibrillization, while the treated samples showed a more developed fibrous network, indicating improved dispersion and partial fibrillization of the cellulose filler. These morphological changes suggest that cellulose acted as an effective hardening phase in the TPS matrix. FTIR analysis confirmed the interaction between starch and cellulose by changing the O–H tensile region and the C–O/C–O-C wavebands, indicating hydrogen bonding and improved interfacial compatibility. Overall, the results suggest that ultrasonication enhances cellulose's structural role in TPS and contributes to the formation of a more interconnected composite morphology. This makes the developed material a promising candidate for biodegradable packaging and other environmentally friendly applications.