Morphological, Electromagnetic, and Absorbing Properties of POMA and PAni/Carbon Black Composites

This work deals with the study of radar absorbing materials (RAM) based on conductive composites obtained by synthesis in situ of poly(o-methoxyaniline) (POMA) and polyaniline (PAni), respectively, on carbon black (CB) particles. Samples containing 20 wt.% of POMA/CB and 20 wt.% of PAni/CB in epoxy resin were prepared. Electrical conductivity results show that POMA/CB (7.9 × 10−2 S cm−1) and PAni/CB (4.1 × 10−1 S cm−1) composites present higher values than the neat POMA (5.4 × 10−4 S cm−1) and PAni (5.5 × 10−2 S cm−1) polymers. SEM analyses show that both composites present different morphologies, characterized by irregular agglomerates of CB and conducting polymers particles. Experimental measurements of the electrical permittivity and magnetic permeability of the composites in epoxy resin were performed in the frequency range of 8.2–12.4 GHz (X-band). From these parameters, computational simulations of reflection loss (RL) of the prepared RAM were performed aiming to evaluate the microwave attenuation performance of the composites in epoxy resin. These simulations considered the influence of sample thicknesses. The computational predictions of RAM behavior show a good fit with experimental results. Simulated RL results show that both composites behave as RAM with good results (up to 99.5%) of microwave attenuation in the frequencies of X-band.