Preparation and characterization of compatible thermoplastic dry starch/poly(lactic acid)

In the presence of glycerol and formamide, one-step extrusion processing was used to prepare poly(lactic acid) (PLA)/thermoplastic dry starch (DTPS) blends (50/ 50 wt%) in a single-screw extruder. The rheological study proved that formamide could improve the fluidity of DTPS and DTPS/PLA blends. With increasing the fluidity of DTPS, a highly dispersed and compatible DTPS/PLA could be achieved by scanning electron microscope (SEM). It was also certain that the plasticization of DTPS was improved. At the same time, Fourier transform infrared (FT-IR) spectroscopy proved that formamide not only weakened the interaction of starch molecules, but also improved the interaction between DTPS and PLA. So that the blend could achieve more thermal stability in a compatible blend, as shown in TGA. The improvement of compatible in DTPS/PLA blends was also proved by tensile test and Dynamic mechanical thermal analysis (DMTA) in this article.