The in situ crystallization kinetics of syndiotactic 1

2-polybutadiene (s-PB) from melt has been investigated by synchrotron radiation small-angle X-ray scattering (SR-SAXS) and wide-angle X-ray diffraction(WAXD).The structure evolutions during the isothermal crystallization of s-PB crystallized at different temperatures have been observed.The results obtained from the scattering peaks in the SR-SAXS curves indicated the development of crystalline structure parameters including long period and lamellar thickness in the isothermal process.The calculated detail information about structure parameters according to the one dimensional electron intensity correction function showed that the long period decreased gradually along with time because the thickness of amorphous layers reduced significantly as the lamellar thickness remained unchanged.The final structures of s-PB about the lamellar thickness and the crystallite size were obtained from SAXS and WAXD

respectively.The line widths were measured for s-PB by WAXD for the selected L110 refection to determine the crystallite size according to Scherrer equation.The lamellar thickness and semi-crystallite size were directly proportional to 1/T∞c-T

which can be explained by the mesomorphic phase theory on polymer crystallization.