Synthesis and properties of novel aromatic polyamides derived from 1,5-bis(4-aminophenoxy)naphthalene and aromatic dicarboxylic acids

A new bis(phenoxy)naphthalene‐containing diamine, 1,5‐bis(4‐aminophenoxy)naphthalene, was synthesized in two steps from the condensation of 1,5‐dihydroxy‐naphthalene with p‐chloronitrobenzene in the presence of potassium carbonate, giving 1,5‐bis(4‐nitrophenoxy)naphthalene, followed by hydrazine hydrate/PdC reduction. A series of polyamides and copolyamides were synthesized by the direct polycondensation of the diamine with various aromatic dicarboxylic acids or with mixed dicarboxylic acids in N‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. The polymers having inherent viscosity of 0.81–1.25 dL/g were obtained in quantitative yield. Most of the polymers were generally soluble in aprotic solvent such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, etc. The polymers derived from rigid dicarboxylic acids such as terephthalic acid, naphthalene dicarboxylic acid, and 4,4′‐biphenyldicarboxylic acid exhibited crystalline patterns. Glass transition temperatures of polymers were in the range of 230–360°C, and 10% weight loss temperatures in nitrogen and air were above 492 and 470°C, respectively. © 1993 John Wiley & Sons, Inc.