Thermo-mechanical characterization of plasticized PLA: Is the miscibility the only significant factor?

PLA is a widely used polymer which has received much attention in the last decade because of its originating from renewable resources and its potential biodegradability. PLA fulfils the packaging industry's requirements for most of the rigid objects but the polymer needs to be plasticized to be used as soft films. In this work, agreed plasticizers for food contact were melt mixed with L-PLA and then, the glass transition, melting, crystallization and mechanical properties of the blends were investigated. The experimental results were compared to the predicted results found through empirical interaction parameters and Fox equations. Molecular scale miscibility is assumed in the amorphous phase whatever the plasticizer. The mobility gained by the PLA chains in the plasticized blends yields crystallization, which is the driving force for various scale phase separations.