AbstractA series of new polyphenylquinoxalines (PPQ) containing alkylenedioxy units within the backbone were prepared in high molecular weight forms (ηinh= 0.82–1.5 dL/g). The glass transition temperatures ranged between 203 and 241°C, decreasing with increasing length of the alkylenedioxy groups. Solution‐cast films gave tensile strength, tensile modulus, and elongation at room temperature as high as 14,400 psi, 378,000 psi, and 8.1, respectively. The PPQ were readily compression molded to provide compact tension specimens that gave fracture energy (GIc) as high as 10.5 in. lb/in.2Titanium to titanium tensile shear specimens provided average strengths of 4400 psi at 26°C, 3100 psi at 177°C, and 2010 psi at 203°C. The PPQ were resistant to normal aircraft fluids but were soluble in chlorinated
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