A novel approach to extract morphological variables in crystalline polymers from time-resolved synchrotron SAXS data

A novel approach to extract morphological variables in crystalline polymers from time-resolved SAXS data using the method of correlation and interface distribution functions has been devised. The principle of the calculation is based on two alternative expressions of Porod's law using the form of the interference function. The approach enables the continuous estimate of the Porod constant, and corrections for liquid scattering and finite interface between the two phases, from the time-resolved data. A model of lamellar morphology has been implemented to interpret the calculated correlation and interface distribution functions. Many detailed morphological variables such as lamellar long period, thicknesses of crystal and amorphous phases, interface thickness, and scattering invariant can be estimated. An example analysis of isothermal crystallization in PET measured by synchrotron SAXS is demonstrated.