Influence of thermo-oxidative aging on the mechanical performance of three-dimensional braided carbon fiber-glass fiber/bismaleimide composites

The bending and shear properties of the three-dimensional braided carbon fiber-glass fiber/bismaleimide composite and the laminated carbon fiber-glass fiber/bismaleimide composite were investigated aging at 200℃ and 250℃ for 10, 30, 90, 120, and 180 days, respectively. The results show that the interfacial performance of the fiber/matrix decreases significantly with the prolonged aging time in a hot oxygen environment, and the bending and shear retention rates of braided composite are better than the laminated composite. This is because Z-binder yarns in the thickness direction of braided composite bundle all yarns into an integral structure to resist external load, and the existence of Z-binder yarns can prevent the expansion of cracks and slow down the aging rate of composites when cracks occur between composites due to thermal-oxidative aging. This means that the integrated structure of braided composite can compensate the mechanical performance degradation caused by hot oxygen aging compared with the laminated composite.