Influence of MWCNTs addition on the electromagnetic absorption performance of polymer-based wave absorber

Multi-Walled Carbon NanoTubes (MWCNTs) have been incorporated into polypropylene (PP) to fabricate electromagnetic (EM) absorbers for electromagnetic interference (EMI) shielding. A low concentration of MWCNTs is maintained to minimize the reflection and transmission of EM waves at the material interface, and it requires ensuring a flawless dispersion of the nanotubes. Experimental investigations of hybrid nanocomposite made of MWNCNTs/PP/epoxy have been carried out using a waveguide measurement setup in X-band frequency range. In-situ polymerization was used to make composite materials with MWCNT mass contents from 0 to 3 wt% in PP/epoxy matrix to increase microwave absorption. The findings regularly correlated with the conductivity values of PP/MWCNTs/epoxy nanocomposite materials. Reflection loss (RL) increases with wt% for 0.5 wt% to 1.5 wt% in the X-band; further reinforcement diminishes absorption performance but is higher than epoxy composite. The research reveals that the percolation threshold is achieved with a low mass content of MWCNT (1.5 wt%), alongside an exceptional EM absorption performance, with effectiveness reaching as high as -12.5 dB in entire X – band range. The experimental findings and literature concur well when systematically altering incident wave frequency, filler concentration, and sample thickness. This design enables one to accurately demonstrate a predetermined level of EM absorption within a specified frequency band.