The effect of thermoforming of PLA-PHBV films on the morphology and gas barrier properties

摘要

Poly(lactic acid) (PLA) is a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, which is a potential candidate to replace conventional polymers in food packaging applications.. Other bio-based materials like polyhydroxyalkanoates (in our case PHBV) could be associated with PLA in order to improve its gas barrier properties and/or its mechanical properties. Two processes, classical 3 layer coextrusion and original polymer blending extrusion, have been used in this study to combine PLA and PHBV to obtain films with different PLA-PHBV structures. The aim of this paper is to compare the thermoformability of the different films and to investigate the final structure in relationship with their gas barrier properties. The effect of the thermoforming steep has been studied by separating heating and stretching effects. We show that the blend morphology offers better mechanical and barrier properties than single PLA or 3 layers PLA/PHBV films.