<scp> <i>Cinnamomum cassia</i> </scp> Extract as a Natural Multifunctional Additive for Plasticized Polylactic Acid

ABSTRACT Polylactic acid (PLA) is a biodegradable polymer with great application potential, but its high brittleness and poor thermo‐oxidative stability limit its broader practical use. Currently, few studies have addressed the simultaneous improvement of PLA toughness and antioxidant performance. In this work, PLA/ATBC–CCE materials were prepared via melt blending, using acetyl tributyl citrate (ATBC) as a plasticizer and Cinnamomum cassia extract (CCE) as a natural antioxidant. The composition and antioxidant activity of CCE were confirmed by mass spectrometry, total phenolic content, and free radical scavenging assays. When the CCE content is 1.00 wt%, PLA/ATBC–CCE 1.00 shows significant improvements relative to the PLA/ATBC matrix, with the oxidation onset temperature 43°C higher, the temperatures at 5 wt% weight loss and at maximum weight loss rate 8.6°C and 26.4°C higher, respectively, and a slight increase in crystallinity. Tensile strength remains nearly unchanged, while elongation at break slightly decreases but maintains ductile behavior. Water vapor permeability and 28‐day composting weight loss increase by about 9.2% and 28.2%, respectively, compared with PLA/ATBC. These findings demonstrate that CCE acts as an effective natural multifunctional additive, providing a viable strategy for the preparation of high‐performance plasticized PLA materials.