Abstract: The crystallization kinetics and the development of lamellar structure during the isothermal crystallization of poly(ε-caprolactone)(PCL) were investigated by means of differential scanning calorimetry(DSC) and real-time synchrotron small angle X-ray scattering(SR-SAXS) techniques, respectively. The Avrami analysis was performed to obtain the kinetics parameters. The value of Avrami index, n, is about 3, demonstrating a three-dimensional spherulitic growth on heterogeneous nuclei in the process of isothermal crystallization. The activation energy and the surface free energy of chain folding for isothermal crystallization were determined according to the Arrhenius equation and Hoffman-Lauritzen theory, respectively. In the process of nonisothermal crystallization of PCL, the value of Avrami index, n, is about 4, which demo
nstrates a three-dimensional spherulitic growth on homogeneous nuclei. In addition, lamellar parameters were obtained from the analysis of SR-SAXS data. The results indicate that long period and the thickness of amorphous layer firstdecrease and then keep constant with the increase of the crystallization time. At the same time, the long period increases with increasing the crystallization temperature, which is the same as the thickness of amorphous and crystalline layers.

Key words: Poly(ε-caprolactone), Isothermal and nonisothermal crys tallization kinetics, Lamellar structure