Studies on the thermotropic liquid crystalline polymer. I. Synthesis and properties of polyamide‐azomethine‐ether

Abstract

Abstract A series of polyamide‐azomethine‐ethers was prepared by condensation of 4,4′‐diaminoanilide with 4,4′‐diformyl‐α,ω‐diphenoxyalkane, 4,4′‐diformyl‐3,3′‐methoxy‐α,ω‐diphenoxyalkane, and 4,4′‐diformyl‐3,3′‐ethoxy‐α,ω‐diphenoxyalkane, respectively. The inherent viscosities of polymers were obviously increased when the polymers were treated by heat under nitrogen at 220°C. The thermotropic liquid crystalline properties were examined by DSC, microscope observations, and TGA. All of the polymers, except polymer A‐1, exhibit thermotropic liquid crystalline properties. They also exhibit threaded and/or Schlieren textures examined by the polarizing microscope which indicate a nematic phase. In most cases, the mesophase exists up to ca. 400‐460°C shown by TGA study. The mesophase cannot exist above 400‐460°C because of the thermal decomposition.