Mechanical, dielectric and microwave absorption properties of carbon black (CB) incorporated SiO_2f/PI composites

Structural and functional integrated absorbing materials have received extensive attention in recent years. Single-layer absorbing material composites in X and Ku bands (8.2–18 GHz) were prepared by using different proportion of carbon black (CB) incorporated quartz glass fiber reinforced polyimide resin (SiO_2f/PI). The morphology, mechanical, dielectric and microwave absorbing properties of the composites were investigated. Different contents of CB with different distributions were observed according to the fractural morphology of the composites. When the CB content is up to 8 wt%, the flexural strength of the composite reaches a maximum value of 705 ± 5 MPa. The real and imaginary parts of complex permittivity both show an increasing trend with the CB content increase. Meanwhile, the real and imaginary parts decrease with the increase of frequency, exhibiting frequency-dependent dielectric response. The reflection loss of the composite was calculated based on the transmission line theory, which is in a good agreement with the experiment.