| Popis: |
A series of polybenzimidazoquinazolines (PIQ) were prepared by the condensation of 5, 5′-bis[2(o-aminophenyl)benzimidazole] with phenyl esters of various di- and tricarboxylic acids. Thermomechanical and thermooxidative properties of the neat resins and as matrices in reinforced composites were evaluated at 371°C. A benzimidazoquinazoline copolymer, prepared from diphenyl bisbenzoate and sym-tris(carbophenoxyphenyl) triazine showed excellent retention of thermooxidative and thermomechanical properties at 371°C after 200 hr at 371°C. For example, a Modmor II unidirectional laminate provided flexural strength and modulus at 371°C, respectively, of 112, 000 psi and 15.6 × 106 psi after 1 hr and 108, 000 and 16.4 × 106 psi after 200 hr in circulating air. |
