Silylated PCL-Based Polyurethane with Shape Memory Effect

Poly(ε-caprolactone) (PCL) diols with low average degree of polymerization (DPn is 10-50) were prepared by bulk polymerization from ε-caprolactone initiated by the mixture of PEG400 and titanium alkoxide. These PCL diols were used to react with 4,4′-diphenylmethane diisocyanate and 3-aminopropyltriethoxysilane in sequence using N,N-dimethylformamide as solvent. After removal of the solvent, the silylated PCLbased polyurethanes (SPCLU) were obtained by moisture curing. The effect of the PCL block DPn on the crosslinking, crystallization behavior, tensile properties and shape memory properties of SPCLU networks were studied in detail. Results show that the crystallinity, melting point, tensile modulus, and elongation at break of SPCLU increase with increasing the PCL block DPn from 10 to 50, whereas the crosslinking density of SPCLU decreases. The SPCLUs with PCL block of high crystallinity show good shape memory effect. The shape recovery ratio is 95%-100% and the shape recovery temperature corresponds to the crystalline melting temperature of PCL block in the copolymer.