Spectroscopic study of rotation-crystalline modifications of mixtures of n-paraffins C22–C24

The binary solid mixtures of n-paraffins, C22–C24, with different molar ratios of 96:4, 3:1, 2:1, 1:4, 1:5, and 1:10 have been studied by FTIR spectroscopy, X-ray diffraction and differential scanning calorimetry (DSC). Temperature-dependent studies of Davydov splitting value, Dn1;2; of in-phase CH2 rocking vibrations have been shown to allow the determination of DTrot temperature intervals, where rotation-crystalline states, characterized by different types of molecular motion, exist. The comparison of the DTrot values obtained by FTIR and DSC methods with the corresponding temperature-dependent X-ray powder diffraction data has shown their good agreement. q 2004 Elsevier B.V. All rights reserved