Processible Aromatic Polyamides Derived from 2,5-Bis(4-Aminophenyl)-3,4-Diphenyl Thiophene and Aromatic Diacid Chlorides

Abstract

Rigid polymers have been of great interest in recent years because of their outstanding mechanical properties and potential applications for the high performance materials. The rigid polymers, however, are almost nonprocessible and structural modifications to improve processibility have been the subject of investigation thereafter. Attempts were made by introducing the flexible linkages or nonlinear aromatic moieties in the polymer main chain^1–7 and by coupling of flexible side chains.^8–13 Attachment of flexible alkoxy side chains to the several rigid polymers were proven to be successful to lower the transition temperatures and to enhance the solubility of polymers. The flexible side chains apparently act as a bound solvent, also yielding a layered mesophase of the polymer chains. The layered mesophase and systematic changes with side chain length also have been of interest in these rigid polymers. In this work we prepared polyamides having bulky rigid moiety in the main chain and alkoxy side chains. We report the synthesis and properties as well as molecular packing behavior associated with the side chains.