Electromagnetic, Morphological, and Electrical Characterization of POMA/Carbon Nanotubes-Based Composites

This study involves the preparation of conducting composites based on poly(o-methoxyaniline) (POMA) and carbon nanotubes (CNT) and the evaluation of them as radar absorbing materials (RAM), in the frequency range of 8.2-12.4GHz (X-band). The composites were obtained by synthesis in situ of POMA in the presence of CNT (0.1 and 0.5 wt% in relation to the o-methoxyaniline monomer). The resulting samples-POMA/CNT-0.1 wt% and POMA/CNT-0.5wt%-were incorporated in an epoxy resin matrix in the proportion of 1 and 10wt%. FT-IR analyses show that the POMA was successfully synthesized on the CNT surface. SEM analyses showthat the synthesizedPOMArecovered allCNTsurface. Electrical conductivitymeasurements showthat theCNTcontributed to increase the conductivity of POMA/CNT composites (1.5-6.7 S.cm(-1)) in relation to the neat POMA (5.4 x 10(-1) S.cm(-1)). The electromagnetic characterization involved themeasurements of complex parameters of electrical permittivity (epsilon) andmagnetic permeability (mu.), using a waveguide in the X-band. From these experimental data reflection loss (RL) simulations were performed for specimens with different thicknesses. The complex parameters show that the CNT in the composites increased epsilon and mu These results are attributed to the CNT network formation into the composites. Simulated RL curves of neat POMA and POMA/CNT in epoxy resin show the preponderant influence of POMA on all RL curves. This behavior is attributed to the efficient CNT recovering by POMA. RL results show that the composite based on 10wt% of POMA/CNT-0.5 wt% in epoxy resin (9mm thickness) presents the best RL results (approximate to 87% of attenuation at 12.4GHz).