Synthesis and thermal behavior of thermotropic terpolymers based on 8‐(3‐hydroxyphenyl)octanoic acid, 2,6‐naphthalenedicarboxylic acid, and substituted hydroquinones

Abstract

Aromatic–aliphatic thermotropic liquid crystalline terpolyesters derived from 2,6‐naphthalenedicarboxylic acid, hydroquinones, and 8‐(3‐hydroxyphenyl)octanoic acid (HPOA), a monomer with built‐in kink and flexible moieties, were prepared by a melt polycondensation reaction. These polymers were characterized for their thermotropic liquid crystalline properties. The effect of variation in the composition of the polyester on the liquid crystalline behavior and thermal properties was also studied. Increasing the content of kinked units increased the amount of structural irregularity and decreased the isotropization temperature. The Tm and thermal stability of the polyesters were found to decrease with increase in the HPOA content. The formation of the liquid crystalline phase was not prevented by the introduction of up to 40 mol % of HPOA in the copolyester. The effect of substituents on the thermal properties of the terpolyesters was also studied. Introduction of a phenyl substituent on the hydroquinone ring was found to lower the transition temperature compared to substituents such as methyl or methoxy. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1021–1029;2001

Ultrasonic Mechanical, Dialectical and Morphology Characterizations of Unsaturated Copolyesters and Terpolyesters

“…For most polymer materials Poisson's ratio tending to 0.5. This can be noticed as a shift from elastic to viscoelastic [30]. Nowadays, many studies were focused on the formation of unsaturated polyester composites and their mechanical properties [31].…”