Abstract: A series of fully biodegradable composites were prepared by melt blending thermoplastic starch(TPS) and poly(butylene adipate-co-terephthalate) (PBAT) using a twin screw extruder．The microstructure and fracture behavior of the composites were studied with scanning electron microscopy(SEM) before and after drawing, the properties of the composites with different compositions were tested．The results indicated that the skin-core structure formed after injection, TPS was inclined to disperse in the core and then distributed from core to skin with increasing content of TPS. It was obviously that the continuous fiber morphology from core to skin can improve the mechanical properties of composites, the addition of TPS also can change the stress-strain behavior of composites, of which took a transition from semicrystalline polymer stress-strain behavior to typical yield cold-drawing behavior.

Key words: poly(butylene adipatecoterephthalate), thermoplastic starch, fibrillar morphology