Synthesis and characterization of new soluble aromatic polyamides derived from 1,4-bis(4-carboxyphenoxy)-2, 5-di-tert-butylbenzene

Aromatic polyamides based on a novel bis(ether-carboxylic acid) were synthe sized by the direct phosphorylation condensation method. 1,4-Bis(4-carboxyp henoxy)-2,5-di-tert-butylbenzene was combined with various diamines contain ing flexible linkages and side substituents to render a set of eight novel aromatic polyamides. The polymers were produced with high yields and modera te to high inherent viscosities (0.49-1.32 dL/g) that corresponded to weigh t-average and number-average molecular weights (by gel permeation chromatog raphy) of 31,000-80,000 and 19,000-50,000, respectively. Except for a singl e example, the polyamides were essentially amorphous and soluble in a varie ty of common solvents such as cyclohexanone, dioxane, and tetrahydrofuran. They showed glass-transition temperatures of 250-295 degreesC (by different ial scanning calorimetry) and 10% weight loss temperatures above 460 degree sC, as revealed by thermogravimetric analysis in nitrogen. Polymer films, o btained by casting from N,N-dimethylacetamide solutions, exhibited good mec hanical properties, with tensile strengths of 83-111 MPa and tensile moduli of 2.0-2.2 GPa. (C) 2001 John Wiley & Sons, Inc.