The Role of Compatibilization in Stretchable Biodegradable <scp>PBAT</scp> / <scp>PLA</scp> Films

ABSTRACT This research focuses on the role of entangled network structures in the compatibilization of biodegradable blends based on Poly(butylene adipate‐co‐terephthalate) (PBAT)/Poly(lactic acid) (PLA). By using this approach, the main objective is to develop a PBAT‐rich biodegradable blend with high melt strength and elasticity predisposed to orientation when stretched during film manufacturing. Compatibilization was achieved when epoxy, oxazoline, and anhydride‐based chain extenders were incorporated in the presence of a radical initiator, 2,5‐Dimethyl‐2,5‐di(tert‐butylperoxy) hexane, during reactive extrusion. Improved miscibility between PLA and PBAT domains was confirmed through a reduction of 9°C in Δ T g that occurred after radical initiator addition, along with a finer morphology of the compatibilized blend due to interfacial reactions. An increase in shear viscosity by 93% was also obtained, compared to the neat PBAT/PLA blend. The presence of crosslinks in the epoxy‐based compatibilized blend was established via dynamical mechanical analysis. Major orientation tendency due to compatibilization‐driven entanglements resulted in a 62% increase in tensile strength due to thickness reduction during drawing, and a threefold enhancement as a result of the machine direction orientation (MDO).