RIGID ROD MOLECULES AS LIQUID-CRYSTAL THERMOSETS .1. RIGID ROD AMIDES

A series of rigid rod amide monomers based on 2,2′‐disubstituted‐4,4′‐diaminobiphenyl were prepared and characterized by DSC and hot stage polarized light microscopy. The monomers were endcapped with maleimide, nadimide, and methylnadimide functionalities. With one exception, all of the materials could be thermally polymerized. Nematic liquid crystalline behavior was observed in three of the new materials which could be crosslinked in either the nematic or isotropic phase. Fast heating rates with hot stage polarized light microscopy were necessary to determine the melting and phase behavior before substantial crosslinking occurred during the heating process. One of the methylnadimide endcapped monomers also showed lyotropic liquid crystalline behavior. Copyright © 1990 John Wiley & Sons, Inc.