Biodegradable polyesters such as poly(butylene succinate) (PBS), poly(propylene succiriate) (PPS), and poly(butylene succinate-co-propylene succinate)s (PBSPSs) were synthesized respectively, from 1,4-succinic acid with 1,4-butanediol and 1,3-propanediol through a two-step process of esterification and polycondensation in this article. The composition and physical properties of both homopolyesters and copolyesters were investigated via H-1 NMR, DSC, TGA, POM, AFM, and WAXD. The copolymer composition was in good agreement with that expected from the feed composition of the reactants. The melting temperature (T-c), crystallization temperature (T-c), crystallinity (X), and thermal decomposition temperature (T-d) of these polyesters decreased gradually as the content of propylene succinate unit increased. PBSPS copolyesters showed the same crystal structure as the PBS homo-polyester. Besides the normal extinction crosses under the polarizing optical microscope, the double-banded extinction patterns with periodic distance along the radial direction were also observed in the spherulites of PBS and PBSPS. (C) 2008 Wiley Periodicals, Inc.