Poly(lactic acid) (PLA) is a well known biodegradable thermoplastic with excellent mechanical properties that is a product from renewable resources. However, the brittleness of PLA limits its general applications. Using epoxidized soybean oil (ESO) as a novel plasticizer of poly (lactic acid), the composite blend with the twin-screw plastic extruder at five concentrations, 3, 6, 9, 12, and 15 wt %, respectively. Compared with pure PLA, all sets of blends show certain improvement of toughness to different extents. The concentration with 9 wt % ESO increases the elongation at break about 63%. The melt flow rates of these blends with respect to different ESO ratio have been examined using a melt flow indexer. Rheological behaviors about shear viscosity and melt strength analysis are discussed based on capillary rheology measurements. The tensile strength and melt strength of the blends with 6 wt % ESO simultaneity reach the maximums; whereas the elongation at break of the blends is the second highest level. ESO exhibits positive effect on both the elongation at break and melt strength. The results indicate that the blend obtained better rheological performance and melt strength. The content of 6 wt % ESO in PLA has been considered as a better balance of performance. The results have also demonstrated that there is a certain correlation between the performance in mechanical properties and melt rheological characterization for the PLA/ESO blends.

Poly­(lactic acid) (PLA) is well-known as a biocompatible and biodegradable polymer that can be obtained from natural sources. However, the brittleness of PLA is a significant drawback for its wide application. In this study, a poly­(lactic acid) (PLA)/polyurethane elastomer prepolymer (PUEP) dynamically vulcanized system was introduced and studied in detail. The torque, FTIR spectrum, and gel content demonstrated that PUEP was vulcanized and that the isocyanate (−NCO) group in PUEP was successfully reacted with the −OH groups at both sides of the PLA. The scanning electron microscopy (SEM) revealed that a relatively uniform phase morphology and good interfacial compatibilization were achieved in the dynamically vulcanized blends. The interfacial reaction and compatibilization between the component polymers resulted in the formation of supertoughened PLA/PUEP blended materials.

Polylactide/TiO2 nanocomposites with different contents of nanoscale TiO2 were prepared by melt blending with a vane extruder in this work.