Abstract:The ring-opening polymerization of ε-caprolactone (ε-CL) initiated with 1,4-butanediol (BDO) was used to make polyols as soft segment. Four polymers with various molecular weights were obtained by controlling mole ratio. They reacted with diisocyanate (HDI) and then hydroxyethyl methacrylate (HEMA) to get polyurethane acrylate (PUA) with a reagent ratio of n(polyol)∶n(diisocyanate)∶n(hydroxyethyl methacrylate)=1∶2∶2. PUA membrane was prepared by dissolving PUA pre-polymer in DMF (60%) added with PI184 photoinitiator and exposing to UV light. The structure and composition of polyurethane acrylates were characterized by attenuated total reflection Fourier transformed infrared spectrometer (ATR-FT-IR), 1H-NMR and GPC. Differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), dynamic thermo mechanical analysis (DMA) and mechanical properties testing were carried out to investigate the thermal and mechanical properties of PUA membranes. Their shape memory performance was analyzed by DMA (stress control mode). It is found that when the molecular weight of the soft segment exceeds 2000, the PUA membrane shows an excellent shape fixing rate and recovery rate (≥98%) with good repeatability.