Poly(lactic acid) plasticized with low-molecular-weight polyesters: structural, thermal and biodegradability features

Poly(lactic acid) (PLA) was plasticized with ester oligomers having different structure, molecular weight and carboxylic acid content as end-functionalities. In particular PLA oligomers and a low-molecular-weight polyester of adipic acid and 1,2-propanediol (an adipate-based derivative) were used and compared. The plasticizing capability was tested and the final structural and thermal properties of PLA matrix were evaluated by correlating the various features to the chemical and physical characteristics of these additives. SEC, DSC, TGA, tensile tests, XRD and SEM results, even after annealing, were collected, and the related data analysed and evaluated with reference to additive starting properties. All the oligoesters were able to generate flexible compounds, but PLA oligomers provided mixtures with reduced structural and thermal stability. Finally, the best performing blend was tested for biodegradability to definitely assess the material suitability for the final application (sustainable packaging). © 2017 Society of Chemical Industry.