PLA/PHBV Films with Improved Mechanical and Gas Barrier Properties

Blending poly(lactic acid) (PLA) with a small amount of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV; 10wt%) using a custom multilayer co-extrusion process increases both ductility and gas barrier properties of extruded films compared with neat PLA and classical blending methods. The co-extrusion process allows multiplication of the number of alternate layers of PLA and PHBV within a film. It was observed that for a critical number of theoretical layers, PHBV layers are broken into lamellas. A well-developed lamellar morphology, with thin and long lamellas of highly crystalline PHBV in PLA matrix was obtained. A balance between aspect ratio and crystallinity of the lamellas, and their dispersion within the PLA matrix was needed to obtain films with improved permeability and mechanical properties.