Thermotropic liquid‐crystalline polyesters and polyesteramides

Thermotropic behaviour is observed in a number of aromatic polyesteramides containing p‐phenylene or substituted p‐phenylene groups. In such polymers, a substantial proportion of co‐polymerised units lacking rigid rod structure can be tolerated without loss of thermotropic behaviour. Anisotropic melts can be formed at very short average chain length. The upper temperature limit of stability of the anisotropic phase is lower the shorter the average chain length and the greater the proportion of relatively flexible units. Some polyesteramides formally derived from p‐N‐methylaminophenol also exhibit thermotropic behaviour.