Chin‐Ping Yang, Jyh-An Chen
Nov 1, 1999
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Journal
Polymer Journal
Abstract
New polyamides (PAs, III-Aa-h) were synthesized by the direct polycondensation of 1,4-bis(4-aminophenoxy)naphthalene (I-A) with various aromatic dicarboxylic acids. These polymers were obtained in quantitative yields with inherent viscosities of 0.84—1.26 dLg−1. Except for III-Aa,e, most of the polymers were soluble in aprotic polar solvents such as N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP), and could be solution cast into transparent, flexible and tough films. The glass transition temperatures of these polyamides ranged from 250—288°C. Thermogravimetric analyses confirmed that these polymers were fairly stable up to 430°C, and 10% weight loss temperatures were recorded in the range of 493–523°C under nitrogen and 483–500°C under air atmosphere. Compared to polyamides with similar structures like 1,5-bis(4-aminophenoxy)naphthalene (series III-B) and 1,4-bis(4-aminophenoxy)benzene (series III-C) or the isomeric 1,4-bis(4-carboxylphenoxy)naphthalene (series IV), the solubility of III-Ad Was higher than III-Bd and III-Cd in DMAc and NMP, while other polymers III-A showed higher solubility than those of III-C in pyridine and m-cresol. The crystallinity of series III-A was lower than III-B, III-C, and IV. Polymers of III-A also exhibited better thermal stability than those of series IV.