ISSN:
0887-624X
Keywords:
aromatic polyamides
;
ether-dicarboxylic acids
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
4,4′-(1,4-Phenylenedioxy)dibenzoic acid (3), 4,4′-(2,5-tolylenedioxy)dibenzoic acid (Me-3), and 4,4′-(2,5-biphenylenedioxy)dibenzoic acid (Ph-3) were prepared by the nucleophilic substitution reaction of p-fluorobenzonitrile with hydroquinone, methylhydroquinone, and phenylhydroquinone, respectively, followed by alkaline hydrolysis. Several aromatic polyamides having inherent viscosities of 0.66-1.34 dL/g were directly prepared by a Yamazaki phosphorylation polyamidation technique from dicarboxylic acids 3, Me-3, and Ph-3, respectively, with aromatic diamines using triphenyl phosphite and pyridine as condensing agents. The solubility of methyl- or phenyl-substituted polyamides was remarkably enhanced when compared to that of nonsubstituted analogues. Most of the substituted polyamides revealed an amorphous nature and were readily soluble in a variety of organic solvents including N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide, dimethyl sulfoxide, and m-cresol. Transparent, flexible, and tough films of these polymers could be cast from the DMAc or NMP solutions. These films had tensile strength of 60-100 MPa, elongation to break of 6-11%, and tensile modulus of 1.68-2.25 GPa. The glass transition temperatures (Tg) of most polyamides could be determined by differential scanning calorimetry (DSC) and were in the range of 200-232°C. Thermogravimetric analyses established that these polymers were fairly stable up to 450°C, and the 10% weight loss temperatures were recorded in the range of 458-535°C in nitrogen and 468-528°C in air atmosphere. In general, the phenyl-substituted polyamides exhibited relatively higher Tg, thermal stability, and solubility. © 1996 John Wiley & Sons, Inc.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
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