Influence of chain extender on mechanical, thermal and morphological properties of blown films of PLA/PBAT blends

Blown films of poly (lactic acid)/poly (butylene adipate-co-terephthalate) (PLA/BAT) blends were prepared in compositions of 40/60 and 60/40. A multifunctional epoxy chain extender, Joncryl ADR 4368, was used as compatibilizer. Both the morphology and the mechanical behavior of the blown films were investigated. The results showed that their morphology is dramatically affected by the chain extender and the blend composition. The mechanical properties were significantly changed due to the generated morphology. All blends showed increase in the modulus of elasticity, but the elongation and the stress at break showed significant increase in the 40% PLA composition without the chain extender, but in compositions with 60% PLA only with the chain extender. These results were substantiated by the change in morphology, which was caused by changes in the interfacial tension due to the chain extender, and in the viscosity ratio due to the composition.