Bindegradable polyesters based on 1

4-succinlc acid and different ratios of 1

4-butanediol and 1

3-propanediol units were synthesized from polyeondensation of the appropriate mixture of the monomers．The crystal structure and melt crystallization kinetics of poly(butylene succinate-co-propylene succinate)(PBSPS)copolyesters have been investigated by means of 1H—NMR

WAXD

DSC and POM．The copolyester composed of BS and PS units has been identified to have the same crystal structure as that of paly(butylene succinate)(PBS)homopolymer

suggesting that only PBS sequences crystallize while the PS units are in an amoiphous form．Multiple melting peaks on the melting curves were observed during heating process

and DSC analysis has demonstrated that melt- recrystallization takes place during heating process．Isothermal crystallization kinetics of PBSPS has been analyzed by the well known Avrami equation．The 2．2—2．8 range of Avrami exponential values n of PBSPS in isothermal crystallization indicated that the mechanism of crystallization was a heterogeneous nucleation with spherical growth geometry．The banded spherulites were observed in PBSPS and the spherulitic morphology was affected by the crystallization temperature and the composition of copolyesters．