Investigation of structure and mechanical properties of toughened poly(L-lactide)/thermoplastic poly(ester urethane) blends

In this study, poly(l-lactide) (PLA) is melt-blended with thermoplastic polyurethane (TPU) to modify the brittleness of PLA. An aliphatic ester-based TPU was selected in order to have an ester sensitivity for degradation and an inherent biocompatibility. Using this compatible TPU, there was no need to apply problematic compatibilizers, so the main positive properties of PLA such as biocompatibility and degradability were not challenged. The detected microstructure of PLA/TPU blends showed that when the TPU content was lower than 25 wt %, the structure appeared as sea-islands, but when the TPU content was increased, the morphology was converted to a cocontinuous microstructure. A higher interfacial surface area in the blend with 25 wt % TPU (PLA25) resulted in a higher toughness and abrasion resistance. The various analyses confirmed interactions and successful coupling of two phases and confirmed that melt-blending of PLA with the aliphatic ester-based TPU is a convenient, cost-effective, and efficient method to conquer the brittleness of PLA. The prepared blends are general-purpose plastics, but PLA25 showed an optimum mechanical strength, toughness, and biocompatibility suitable for a wide range of applications. (c) 2015 Wiley Periodicals, Inc.