DSC study of transformation kinetics of liquid-crystallines based on 1,4-phenylene 4-n-methoxybenzoate-4-allyloxybenzoate

The transformation kinetics of liquid-crystalline 1,4-phenylene 4-n-methoxybenzoate-4-allyl-oxybenzoate (PMOBAOB) and a liquid-crystalline poly(mesogen/methyl) siloxane (PMMS) was studied by means of a non-isothermal method using differential scanning calorimetry. This determination led to an apparent activation energy of transformation of 639.0 and 306.5 kJ mol^–1, respectively. The values of the Avrami exponentn were 1.8 and 1.1. The results show that the process of transformation of PMOBAOB involves a constant number of nuclei growing in two dimensions at a constant rate, while the process of transformation of PMMS-PMOBAOB involves a constant number of nuclei growing in one dimension at a constant rate.