Differential thermal analysis is used to examine the kinetics of nucleation associated with the melt phase crystallization of n-alkanes in the homologous series C13H28 to C32H66. Crystallization studies from stagnant melt samples reveal a direct correlation between structural type and nucleation behavior, notably demonstrating an alternating behavior between the even and odd carbon number homologues which decreases in extent as a function of increasing chain length. This effect is mirrored in calculations of the lattice energies based on the crystallographic structures with greater lattice stability being found for the even carbon number n-alkanes which crystallize in the triclinic crystal structure. The data are consistent with a heterogeneous nucleation mechanism associated with preferential nucleation at the free surface of the sample associated with surface freezing.
|Number of pages||7|
|Publication status||Published - 13 Nov 1996|