In this Project epoxy-based composites loaded with carbon nanotubes were prepared, with the aim of evaluating their applicability as electromagnetic shields in the GHz frequency range. For this purpose, two different methods of nanoreinforcement dispersion have been attempted: infiltration of the epoxy within a preformed laminar structure of carbon nanotubes (buckypaper) and direct high-energy ultrasonic dispersion of carbon nanotubes in the uncured matrix. Through these techniques composites were manufactured and their electromagnetic shielding efficiency has been assessed. The results have been justified based on the morphological differences of carbon nanotubes derived from each preparation method.
Subsequently magnetite-decorated carbon nanotubes were incorporated by ultrasonic dispersion, in order to study a possible electromagnetic synergy between magnetic inclusions and electric charge carriers. Electromagnetic shielding efficiency of this composite was evaluated and compared with results previously obtained from the materials containing only carbon nanotubes.
Besides electromagnetic shielding characteristics, materials were characterized by complementary methods as Transmission Electron Microscopy (TEM and HR-TEM), X-ray diffraction (XRD) and Vibrating Sample Magnetometry by (VSM).
The results presented suggest that these materials could be suitable as high frequency electromagnetic absorbers. EMI shielding values have been achieved up to 11 dB with a specific thickness of less than 1mm, supporting the relevance of this line of research.