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. M̄w and M̄n of the resultant polymers were 8.0 × 104 and 5.5 × 104 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 °C. The 10% weight loss temperatures of these polymers were found to be up to 500 °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. Copyright © 2009 Society of Chemical Industry
In this research a new structurally-modified monomer, 2,2'-bis[(p-phenoxy phenyl)]-4,4'-diaminodiphenyl ether (PPAPE) was synthesized by a three-step manner starting from 4,4'-dinitrodiphenyl ether. Novel classes of wholly aromatic polyamides and polyimides were prepared from PPAPE through the conventional polycondensation reactions including triphenyl phosphate-activated phosphorylation method for the preparation of the polyamides and cyclodehydration of in situ-formed polyamic acid precursors for the preparation of the polyimides. n and w values were determined by GPC measurements. Crystallinity, organosolubility, and qualitative film characteristics of the resulting aromatic polyamides and polyimides were investigated. A low crystallinity extent was only observed using their wide-angle X-ray diffractograms. All polymers had excellent organosolubility in common polar solvents such as DMAc, DMF, DMSO, and NMP. The resulting well-designed polymers could also be cast into transparent and flexible films.
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