Effect of carbon black content on electrical and microwave absorbing properties of polyaniline/carbon black nanocomposites

Carbon black coated with polyaniline, forming a core–shell structure, was synthesized by in situ polymerization at different carbon black contents (5–30 wt.%) and introduced into epoxy resin to be a microwave absorber. The spectroscopic characterizations of the formation processes of polyaniline/carbon black composites were studied using Fourier transform infrared, ultraviolet–visible spectrophotometer, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and electron spin resonance. Microwave absorbing properties were investigated by measuring reflection loss in the 2–18 and 18–40 GHz microwave frequencies range using the free space method. The results showed that a wider absorption frequency range could be obtained by adding different carbon black contents in polyaniline.