Synthesis and characterization of poly(ε-caprolactone)-diol prepolymers

Two series of dihydroxyl-terminated poly-e-caprolactone(PCL-diol) and poly-e-caprolactone-poly(ethylene glycol)-poly-e-caprolactone(PCL-PEG-PCL) were prepared via ring-opening polymerization of e-caprolactone using stannous octoate as catalyst and ethylene glycol or PEG as initiator.The chemical structures and properties of the resulting products were measured with FT-IR,1HNMR,DSC,GPC and XRD.The results indicate that the polymer molecular weights can be controlled by adjusting the ratio of monomer to initiator.DSC shows that the melting point increase and crystallinity of PCL-diol is improved from 58% to 72% with increasing of the polymer molecular weight and melting point of PCLPEG-PCL rise up to 69.3℃ with increasing of the molecular weight of the PEG.Crystallinity of PCL-PEG-PCL is improved by introducing PEG,and microphase-separation in the products is observed by XRD.