A series of aliphatic biodegradable poly(ether-ester)s based on poly(butylene succinate)(PBS)as hard segment and poly(tetramethylene oxide)(PTMO,M_n=1 000 g/mol) as soft segment were synthesized.The composition dependence of thermal behavior,morphology and mechanical properties was investigated by differential scanning calorimetry(DSC),atomic force microscopy(AFM),and tensile testing.The crystallization temperature(T_c) and melting temperature(T_m) of the PBS block within poly(ether-ester)s decrease steadily at first,but decrease sharply with PTMO content above 50 wt%.Two crystallization peaks were detected for PTMO in PBSPTMO60 sample,suggesting the occurrence of fractionated crystallization.The crystallization enthalpies(△H_c) and melting enthalpies(△H_m) of PBS block decrease at first,then increase as PTMO content increases further.AFM has demonstrated that phase-separated morphology transforms from a phase of continuous hard matrix to one of continuous soft matrix containing isolated hard domain as PTMO content is increased.Finally,the results of tensile testing show that the poly(ether-ester)s present the behavior of plastics when PTMO content is below 40 wt%,and of thermoplastic elastomers with PTMO content above 50 wt%.By varying the composition of copolymer,the aliphatic poly(ether-ester)s plastics,or especially biodegradable aliphatic poly(ether-ester)s thermoplastic elastomers can be obtained. A series of aliphatic biodegradable poly (ether-ester) s based on poly (butylene succinate) (PBS) as hard segment and poly (tetramethylene oxide) (PTMO, M_n = 1000 g / mol) dependence of thermal behavior, morphology and mechanical properties was investigated by differential scanning calorimetry (DSC), atomic force microscopy (AFM), and tensile testing. The crystallization temperature (T_c) and melting temperature (T_m) of the PBS block within poly -ester) s decrease steadily at first, but decrease sharply with PTMO content above 50 wt% .wo crystallization peaks were detected for PTMO in PBSPTMO60 sample, suggesting the occurrence of fractionated crystallization.The crystallization enthalpies (ΔH_c) and melting enthalpies H_m) of PBS block decrease at first, then increase as PTMO content increases further. AFM has demonstrated that phase-separated morphology transforms from a phase of continuous hard matrix to one of continuous soft matrix containing is The results of tensile testing show that the poly (ether-ester) s present the behavior of plastics when PTMO content is below 40 wt%, and the thermoplastic elastomers with PTMO content above 50 wt % .By varying the composition of copolymer, the aliphatic poly (ether-ester) s plastics, or especially biodegradable aliphatic poly (ether-ester) s thermoplastic elastomers can be obtained.