Abstract:
The polymorphic transformations of tetracosane C$_{24}$H$_{50}$ upon heating were studied using Fourier transform infrared spectroscopy. A violation of the regularity of chains in the cores of the lamellae was revealed based on temperature changes in the progressions of rocking vibrations of CH$_2$ – groups and stretching (skeletal) vibrations of $C$ – $C$- bonds. The occurrence of end gauche defects was discovered, the number of which increases at each transition between intermediate rotator phases (R$_{\mathrm{I}}$, $R_{\mathrm{II}}$, $R_{\mathrm{V}}$). A mechanism for structural rearrangements in tetracosane has been proposed.
Keywords:$n$-alkanes, lamellae, phase transitions, rotator phases, IR spectroscopy.
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