Synthesis and properties of ortho-linked polyamides based on a bis(ether-carboxylic acid) or a bis(ether amine) derived from 4- tert-butylcatechol

Abstract

4- tert-Butyl-1,2-bis(4-carboxyphenoxy)benzene ( 2a) and 1,2-bis(4-aminophenoxy)-4- tert-butylbenzene ( 2b) were synthesized through the aromatic nucleophilic substitution reaction of 4- tert-butylcatechol with p-fluorobenzonitrile or p-chloronitrobenzene in the presence of potassium carbonate in N, N-dimethylformamide. Two series of polyamides with flexible main-chain ether linkages and ortho-phenylene units were prepared from dicarboxylic acid 2a with various aromatic diamines or from diamine 2b with various aromatic dicarboxylic acids via the phosphorylation reaction with triphenyl phosphite and pyridine. The inherent viscosities of these new polyamides were in the range of 0.52–2.60 dl g −1. Almost all the polyamides were noncrystalline and readily soluble in a variety of polar solvents and afforded transparent, flexible and tough films by solution casting. They have useful levels of thermal stability, associated with relatively high glass transition temperatures (most >200°C) and 10% weight loss temperatures in excess of 480°C in nitrogen or in air.