Transformation kinetics of liquid-crystallines based on 1,4-phenylene 4-n-Alkylbenzoate-4-Allyloxybenzoate by DSC

The transformation kinetics of a series of liquid-crystallines based on 1,4-phenylene 4-n-alkybenzoate-4-allyloxybenzoate (PABAOB) was studied by nonisothermal methods using differential scanning calorimetry. These determinations led to the values of activation energy of transformation from 691.3 to 628.3 kJ/mol, respectively The values of the Avrami exponent n were from 3.0 to 2.6. The values of transformation activation energy decreased with the ascending of alkyl. The result shows that the process of transformation of PABAOB is a constant number of nuclei growing in three dimensions at constant rate and the crystal growth being controlled probably by a diffusion process. (C) 1997 John Wiley & Sons, Inc.