Innovative Interfacial Compatibilization and Blowing Strategies for Advancing PLA/PBAT Blown Films: Enhancing Film...

The use of biodegradable plastic films as an alternative to traditional plastic films is one of the important ways to address the problem of plastic pollution. However, producing high-quality blown films from polylactic acid (PLA) and polybutylene adipic acid/terephthalate (PBAT) is challenging due to their poor miscibility. In situ reactive compatibilization offers an effective solution to this problem. This study investigates the effects of epoxy equivalent weights (EEW) and molecular weights of an epoxy multifunctional chain extender on the rheological behavior, dynamic thermomechanical properties, film blowing stability, mechanical properties, phase morphology, and barrier properties of PLA/PBAT blends and blown films during reactive processing. The results indicate that ADR 4468, which has a low EEW and a high molecular weight, can significantly enhance interfacial adhesion and phase morphology. The tensile strength and elongation at break of the resulting blown film in the machine direction (MD)/transverse direction (TD) could reach 60.6/57.4 MPa and 608.5/458.3%, respectively, which were 29.8/21.1 and 158.8/89.0% higher than those of the pure PLA/PBAT blown film. Moreover, the oxygen permeability (OP) and water vapor permeability (WVP) are as low as 3.88 × 10^-15 cm³·cm/(cm²·s·Pa) and 1.57 × 10^-13 g·cm/(cm²·s·Pa), respectively. The compatibilized system also enables stable film blowing and retains acceptable visual transparency. These improvements demonstrate the potential of PLA/PBAT/ADR blown films as sustainable and versatile materials for commercial and food packaging applications, owing to their enhanced mechanical and barrier properties coupled with satisfactory transparency.