Monomer Synthesis and Characterization of Novel Aromatic Polyamides

Aromatic polyamides are high performance materials, having outstanding thermal and mechanical properties. Poly(2,5-Diamino-terephthalic acid) (PATA) was designed as a novel aromatic polyamide with high strength and modulus. In this paper, 2,5-Diamino-terephthalic acid (DATA), as a monomer of PATA, was synthesized from 2,5-Dimetyl-1,4-phenyldiamine (DPA). First step was the amidation of DPA by reacting with acetic anhydride to protect amido group. Then N-(4-Acetylamino-2,5-dimethyl-phenyl)-acetamide (AMPA) was oxidized by potassium permanganate. Finally, AMPA was hydrolyzed by sodium hydroxide and the monomer DATA was precipitated by hydrochloric acid around PH 5. DATA and all the intermediate products were characterized and confirmed by (HNMR)-H-1 and FT-IR spectra. They were all in great agreement with the proposed structure. The overall yield of DATA was about 40.0%.