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.
