Synthesis and properties of aromatic polyamides derived from 1,2‐bis(4‐aminophenoxy)benzene and aromatic dicarboxylic acids

Abstract 1,2‐Bis(4‐aminophenoxy)benzene was synthesized in two steps by the preparation of 1,2‐bis(4‐itrophenoxy)benzene from 1,2‐dihydroxybenzene (catechol) and p‐chloronitrobenzene and subsequent reduction with a 10% Pd‐C catalyst and hydrazine hydrate. Aromatic polyamides with an inherent viscosity in the range of 1.08–2.00 dL/g were prepared by the direct polycondensation of this diamine with various aromatic dicarboxylic acids in N‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Most of the polymers formed were soluble in aprotic solvents such as NMP and N,N‐methylacetamide (DMAc), and afforded transparent, flexible, and tough films upon casting from DMAc solutions. Most of the cast films showed obvious yield points in their stress‐strain curves and had tensile strength among 64–89 MPa, elongation at break among 5–23%, and initial modulus in 1.7–2.5 GPa. The glass transition temperatures (Tg) of these polymers were in the range of 207–278°C, and the 10% weight loss temperatures were recorded above 475°C in nitrogen and above 452°C in air.