SYNTHESIS AND PROPERTIES OF AROMATIC POLYAMIDES DERIVED FROM 1,6-BIS(4-AMINOPHENOXY)NAPHTHALENE AND AROMATIC DICARBOXYLIC-ACIDS

A new bis(phenoxy)naphthalene-containing diamine, 1,6-bis(4-aminopheno xy)naphthalene, was synthesized in two steps from the condensation of 1,6-dihydroxynaphthalene with p-chloronitrobenzene in the presence of potassium carbonate, giving 1,6-bis(4-nitrophenoxy)naphthalene, follow ed by hydrazine hydrate/Pd-C reduction. A series of polyamides were sy nthesized by the direct polycondensation of the diamine with various a romatic dicarboxylic acids in the N-methyl-2-pyrrolidone (NMP) solutio n containing dissolved metal salts such as CaCl2 or LiBr using triphen yl phosphite and pyridine as condensing agents. The polymers were obta ined in quantitative yield with inherent viscosities of 0.78-3.72 dL/g . Most of the polymers were soluble in aprotic solvents such as N,N-di methyl- acetamide (DMAc), N,N-dimethylformamide (DMF), NMP, and they c ould be solution-cast into transparent, flexible and tough films. The casting films had tensile strength of 102-175 MPa, elongation at break of 8-42%, and tensile modulus of 2.4-3.8 GPa. The polymers derived fr om rigid dicarboxylic acids such as terephthalic acid and 4,4'-bipheny ldicarboxylic acid exhibited some crystalline characteristics. The gla ss transition temperatures of the polyamides were in the range of 238- 337 degrees C, and their 10% weight loss temperatures were above 487 d egrees C in nitrogen and above 438 degrees C in air. (C) 1995 John Wil ey and Sons, Inc.