Synthesis and properties of soluble aromatic polyamides derived from 2.2 '-bis(4-carboxyphenoxy)-9,9 '-spirobifluorene

Abstract

The synthesis of a new bis(ether carboxylic acid), 2,2'-bis(4-carboxyphenoxy)-9,9'-spirobifluorene, in which two orthogonally arranged carboxyphenoxyfluorene entities are connected through an sp(3) carbon atom (the Spiro center), is reported. The direct phosphorylation polycondensation of this diacid monomer with various aromatic diamines yields aromatic polyamides containing 9,9'-spirobifluorene moieties in the main chain. The presence of the spiro segment restricts the close packing of the polymer chains and decreases interchain interactions, resulting in amorphous polyamides with enhanced solubility, and high glass-transition temperatures and good thermal stability are maintained through controlled segmental mobility. The glass-transition temperatures of these polyamides are in the range of 234-306degreesC, with 10% weight losses occurring at temperatures above 530 degreesC. (C) 2003 Wiley Periodicals, Inc.