MP/tubular-CF composite carbon foam of high microwave absorption and electromagnetic interference shielding properties

Abstract

The MWA material hopes to achieve sufficiently low reflection loss, while the EMI shielding pursues sufficiently high electromagnetic shielding efficiency. At present, EMI shielding materials pursue sufficiently low reflection losses to avoid secondary pollution of electromagnetic waves. Therefore, it is the goal pursued by researchers of developing a material with enough high absorption loss and sufficiently low reflection loss. For this purpose, mesophase pitch/hollow carbon fiber composite carbon foam (MP/tubular-CF) was prepared by high-pressure pyrolysis. It was found that tubular-CF could effectively regulate the pore cell structure of the MP/tubular-CF. Meanwhile, tubular-CFs distributed randomly form a complete conductive network in composites, thereby improving the dielectric loss performance of composites. In addition, tubular-CF distributed randomly in composites result in more defects and heterogeneous interfaces which enhancing the electromagnetic wave loss performance. Of the prepared samples, MP/tubular-CF-9 exhibits the minimum reflection loss (RLmin) of −37.84 dB, as high as 32.47 dB of average total shielding efficiency, and 15.06 MPa of compressive strength simultaneously. This work proved a strategy that the synergistic regulation of pore cell structure, conductivity and defects are achieved in the process of composites preparation, which enables the composites to obtain simultaneously excellent MWA performance, EMI shielding performance and compressive strength.