Blends were prepared from poly(lactic acid) (PLA) and thermoplastic starch (TPS) to study component interactions, structure and properties. Starch was plasticized with glycerol at two levels, at 36 and 47 wt %. The results unambiguously showed that the interaction of the two components is weak. The investigation of the possible partitioning of glycerol in the two phases indicated that most of the plasticizer is located in the TPS phase. Thermodynamic modeling predicted some dissolution of PLA in TPS which was assisted by the presence of the plasticizer, but TPS did not dissolve in PLA at all. No tangible proof was found for the formation of a glycerol rich phase in TPS, the relaxation transition assigned to this phase was rather explained with the movement of smaller structural units of starch molecules. Weak interfacial adhesion does not allow stress transfer through the interface resulting in poor strength and small deformation. (C) 2016 Elsevier Ltd. All rights reserved.