AbstractIn this study, three kinds of L‐lactide‐based copolymers, poly(lactide‐co‐glycolide) (PLGA), poly(lactide‐co‐p‐dioxanone) (PLDON) and poly(lactide‐co‐caprolactone) (PLC), were synthesized by the copolymerization of L‐lactide (L) with glycolide (G), or p‐dioxanone (DON) or ε‐caprolactone (CL), respectively. The copolymers were easily soluble in common organic solvents. The compositions of the copolymers were determined by 1H‐NMR. Thermal/mechanical and shape‐memory properties of the copolymers with different comonomers were compared. Moreover, the effect of the chain flexibility of the comonomers on thermal/mechanical and shape‐memory properties of the copolymers were investigated. The copolymers with appropriate lactyl content showed good shape‐memory properties where both the shape fixity rate (Rf)and the shape recovery rate (Rr) could exceed 95%. It was found that the comonomers with different flexible molecular chain have different effects on their thermal/mechanical and shape‐memory properties. Among them, PLGA has the highest mechanical strength and recovery rate while PLC copolymer has high recovery rate when the lactyl content exceeded 85% and the lowest transition temperature (Ttrans). Copyright © 2007 John Wiley & Sons, Ltd.