Completely biodegradable blends of poly (propylene carbonate) (PPC) and poly(butylene succinate) (PBS) were melt-prepared and then compression-molded. The miscibilities of the two aliphatic polyesters, that is, PPC and PBS, were investigated by dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The static mechanical properties, thermal behaviors, crystalline behavior, and melt flowability of the blends were also studied. Static tensile tests showed that the yield strength and the strength at break increased remarkably up to 30.7 and 46.3 MPa, respectively, with the incorporation of PBS. The good ductility of the blends was maintained in view of the large elongation at break. SEM observation revealed a two-phase structure with good interfacial adhesion. The immiscibility of the two components was verified by the two independent glass-transition temperatures obtained from DMA tests. Moreover, thermogravimetric measurements indicated that the thermal decomposition temperatures (T-5% and T-10%) of the PPC/PBS blends increased dramatically by 30-60 degrees C when compared with PPC matrix. The melt flow indices of the blends showed that the introduction of PBS improved the melt flowability of the blends. The blending of PPC with PBS provided a practical way to develop completely biodegradable blends with applicable comprehensive properties. (c) 2007 Wiley Periodicals, Inc.