Epoxidized Safflower Oil–Mediated Reactive Compatibilization for High‐Performance PLA / PBAT Blown Film

Poly(lactic acid) (PLA) and poly(butylene adipate‐co‐terephthalate) (PBAT) are promising biodegradable polyesters; however, their inherent immiscibility limits performance optimization in flexible film applications. In this work, epoxidized safflower oil (ESFO), a bio‐based reactive epoxide, was introduced as a compatibilizer for PLA/PBAT blown films. Interactions between the epoxy groups of ESFO and polyester end groups, confirmed by Fourier transform infrared spectroscopy, enhanced interfacial adhesion, and promoted a more homogeneous morphology. ESFO incorporation markedly improved ductility, with elongation at break reaching up to 245%, while also enhancing thermal stability and barrier properties. An optimal ESFO loading of 2.5 g provided a balanced improvement in oxygen, water vapor, and UV barrier performance. Overall, this work presents an effective bio‐based epoxide‐mediated compatibilization strategy for immiscible biodegradable polyesters, enabling the development of high‐performance and sustainable blown films.