It is very important to manipulate the switch temperature

mechanical properties and degradation rate of biodegradable shape memory polymers(BSMPs) from the viewpoint of practical applications.This can be realized through molecular design of the microstructure of the building blocks of BSMPs.In this study

hydroxy-telechelic poly(L-lactide-co-glycolide) (PLLG-diol) and poly(ε-caprolactone-co-glycolide) (PCG-diol) copolymers with adjustable composition

molecular weight and thermal transition temperature were synthesized via ring opening copolymerization of L-lactide/glycolide and ε-caprolactone/glycolide

respectively.Biodegradable segmented poly(esterurethane)s were then synthesized via reaction with diisocyanate using them as hard and soft segments

respectively.Their molecular weight distribution

thermal transition and thermal induced shape memory behaviors were studied with GPC

DSC and thermomechanical characterization

respectively.Segmented poly(ester-urethane)s exhibit excellent shape memory properties

with strain fixity rate of 98%～99.5% and strain recovery rate of 93%～98.5%.The strain fixity rate is independent of the composition and molecular weight of the segments

but the strain recovery rate increases with increasing the molecular weight or decreasing the GA content in the segments.With controlling the transition temperature of the soft segments

the shape recovery does not occur at body temperature but takes place at a little higher temperature in the range of 40～50℃.This character is very desired for and beneficial to clinical applications.The shape recovery speed can be adjusted by the environmental temperature or the heating rate.