화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals, Vol.515, 49-63, 2009
Crystallization Kinetics Study in Orthogonal Liquid Crystalline Phases Formed by Schiff's Base nO.m Compounds by Calorimetric and Dielectric Techniques - Part 2
A systematic kinetic study of crystallization among two smectogens of higher homologues of the benzylidene aniline nO.m series viz. 4O.16 and 8O.16 has been carried out by thermal microscopy, differential scanning calorimetry (DSC), and dielectric studies. The crystallization kinetics was studied by two techniques, viz., the traditional thermal analysis (i.e., DSC) and dielectric studies, viz., permitivitty and dielectric loss variation with temperature. The DSC thermo grams were run from crystallization temperature to the isotropic melt for different time intervals. The liquid crystalline behavior together with the rate of crystallization of Smectic ordering in newly synthesized nO.m compounds were discussed in relation to the kinetophase (which occurs prior to the crystallization). The molecular mechanism and dimensionality in the crystal growth were computed from the Avrami equation. The characteristic crystallization time (t*) at each crystallization temperature was deduced from the individual plots of log t and H. Further, it was observed that the data obtained from DSC and dielectric studies were in good agreement with one another.