Isothermal Crystallization of Long Paraffins –A Correlation Analysis

The small-angle X-ray scattering (SAXS) curves on ultra-long n-alkanes obtained by Ungar and Keller at different times after reaching the crytallization temperature have been Fourier analysed and the correlation curves so obtained at different temperatures and different annealing times reflect sensitively all those morphological features which are broadly characteristic of the scattering curves. In addition the correlation curves beautifully show a transition from a non-integer-fraction (NIF) length to extended (E) chain structure. Some other parameters characterizing the kinetics of morphological features, which are not easily observable in SAXS, such as crystalline and amorphous lengths, degree of order and halfwidths of correlation peaks are also reported.