Preparation and microwave absorbing properties of polyaniline-modified silicon carbide composites

Polyaniline (PANI)/silicon carbide (SiC) composites were prepared by emulsion polymerization using sodium dodecylbenzene sulfonate and ammonium persulfate as emulsifier and oxidant, respectively. The structure and morphology of the composites were characterized by Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), and scanning electron microscopy (SEM). The FTIR and XRD results indicated that there existed an interaction between PANI molecules and SiC particles. The SEM results indicated that SiC particles were covered with the conducting PANI. Microwave absorbing properties were investigated by measuring complex permittivity and complex permeability at 26.5-40GHz. The results showed that the reflection loss (RL) properties of PANI/SiC composites exhibited significant improvements compared with pure SiC. A maximum RL of -36.3dB was observed at 38.6GHz with a thickness of 0.9mm for the composites and the effective absorption band under -10dB reached 6.2GHz.