Synthesis and characterization of novel aromatic polyamides derived from 2,2′-bis(p-phenoxyphenyl)-4,4′-diaminodiphenyl ether

BACKGROUND: Wholly aromatic polyamides (aramids) are high-performance polymeric materials with outstanding heat resistance and excellent chemical stabilities due to chain stiffness and intermolecular hydrogen bonding of amide groups. Synthesis of structurally well-designed monomers is an effective strategy to prepare modified forms of these aramids to overcome lack of organo-solubility and processability limitations. RESULTS: A novel class of wholly aromatic polyamides was prepared from a new diamine, namely 2,2'-bis(p-phenoxyphenyl)4,4'-diaminodiphenyl ether (PPAPE), and two simple aromatic dicarboxylic acids. Two reference polyamides were also prepared by reacting 4,4'-diaminodiphenyl ether with the same comonomers under similar conditions. (M) over bar (w) and (M) over bar (n) of the resultant polymers were 8.0 x 10(4) and 5.5 x 10(4) g mol(-1), respectively. Polymers resulting from PPAPE exhibited a nearly amorphous nature. These polyamides exhibited excellent organo-solubility in a variety of polar solvents and possessed glass transition temperatures up to 200 degrees C. The 10% weight loss temperatures of these polymers were found to be up to 500 degrees C under a nitrogen atmosphere. The polymers obtained from PPAPE could be cast into transparent and flexible films from N,N-dimethylacetamide solution. CONCLUSION: The results obtained show that the new PPAPE diamine can be considered as a good monomer to enhance the processability of its resultant aromatic polyamides while maintaining their high thermal stability. The observed characteristics of the polyamides obtained make them promising high-performance polymeric materials. (C) 2009 Society of Chemical Industry