Ether polyphenylquinoxalines. II. Polymer synthesis and properties

Three polyphenylquinoxalines were prepared by the one‐step solution cyclopolycondensation of 3,3′,4,4′‐tetraaminobenzophenone with three novel bisbenzils containing oxyphenylene groups. High molecular weight polymers were obtained that exhibited good solubility in chlorinated solvents and m‐cresol and formed tough, flexible films from solution. Glass transition temperatures Tg which were determined by thermomechanical analysis, torsional braid analysis, and dielectric loss measurements showed that the inclusion of oxyphenylene units into the polymer chain was effective in reducing the Tg. However, the onset of polymer decomposition, as determined by thermogravimetric analysis and isothermal aging, disclosed that the oxyphenylene units also decreased the thermooxidative stability for two of the polymers studied.