DGEBA-Based Epoxy Resin as Compatibilizer for Biodegradable Poly (lactic acid)/Poly(butylene adipate-co-terephthalate) Blends

Poly (lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are melt blended in a proportion of 50:50 in the presence of diglycidyl ether of bisphenol A (DGEBA) - based epoxy resin, which plays a role of compatibilizing agent and/or chain extender. The increase of torque values during melt mixing and the molar mass of the polymer in the compatibilized blends suggest that DGEBA acts as a chain extender between the polyesters chains. The blend is immiscible with sea-island type morphology, as suggested by scanning electron microscopy. The addition of 3 phr of DGEBA results in a decrease of domain size and a better interfacial adhesion, which is also confirmed by rheological behavior. An increase of modulus and tensile strength of the blend is also observed by the addition of 3 phr of DGEBA. Dynamic-mechanical and thermal properties are also investigated. Therefore, this article provides a new strategy for improving the compatibilization of PLA and PBAT biodegradable polyesters and open new possibilities to develop fully biodegradable polymeric materials.