Properties of biodegradable poly(propylene carbonate)/starch composites with succinic anhydride

Biodegradable composites of poly(propylene carbonate) (PPC) reinforced with granular cornstarch are prepared in a single screw extruder. The effects of succinic anhydride (SA) on the morphology, thermal properties, as well as mechanical properties of PPC/starch composites, are investigated. Scanning electron microscope (SEM) shows that starch surface becomes coarse, the interface is not clear and compatibility is increased when SA is added. Fourier transform infrared (FT-IR) Spectroscopy reveals that SA can improve the interaction between PPC and starch. Thermogravimetric analysis (TGA) results show that SA leads a significant improvement of thermal stability for PPC/starch composites. Mechanical testing illustrates that SA can increase mechanical properties of PPC/starch composites. The yield stresses of PPC/starch composites without SA and with SA are, respectively, 19.20 and 22.94 MPa. SA enhances the properties of PPC/starch composites, which are all ascribed to the improvement of the interaction between PPC and granular starch at the existence of SA.