Raising awareness of the environmental problems induced by the extensive use of plastics has led to further investigations on biodegradable polymers due to their ability to undergo natural decomposition process [1]. However, these materials do not achieve the same mechanical properties as conventional ones, which makes their possible applications very limited. Therefore, current studies focus on adding fillers to biodegradable polymers to develop composites with much better properties. Among these, poly (butylene adipate-co-terephthalate) (PBAT) has received attention owing to its ductility, flexibility, biodegradability and ease of processing [2]. On one side, processing might strongly affect the dispersion of fillers in the polymer matrix leading to the formation of a three-dimensional network and improving the modulus. On the other side, orientation of fillers with high aspect ratio might improve the modulus or the elongation at break. In this framework, this study concerns the incorporation of various cellulosic fillers with different aspect ratio in PBAT polymer matrix by melt mixing. Thermal, mechanical, and rheological properties, as well as the morphology, were studied varying the type and the amount of the cellulosic fillers and the processing method to get a better understanding of the origins of orientation or percolation in bio-composites. References [1] W. Amass, A. Amass, et B. Tighe, « A review of biodegradable polymers: uses, current developments in the synthesis and characterization of biodegradable polyesters, blends of biodegradable polymers and recent advances in biodegradation studies », Polym. Int., vol. 47, no 2, p. 89‑144, 1998. [2] H. Wang, D. Wei, A. Zheng, et H. Xiao, « Soil burial biodegradation of antimicrobial biodegradable PBAT films », Polym. Degrad. Stab., vol. 116, p. 14‑22, 2015.