Optimizing carbon nanotube/polypropylene nanocomposites for enhanced conductivity and EMI shielding

Polypropylene (PP), a widely used polyolefin, suffers from poor electrical conductivity, which limits its use in electronic packaging and electromagnetic interference (EMI) shielding. In this study, conductive and EMI-shielding PP nanocomposites were fabricated using dual-functionalized carbon nanotubes (CNTs) via a solvent-free melt-blending route. Sequential acid and silane treatments improved CNT dispersion and interfacial compatibility, yielding a low percolation threshold of ~0.3 wt.% and an electrical conductivity of 1.2 × 10⁻² S/m at 3 wt.% CNT. At 5 wt.%, the EMI shielding effectiveness exceeded 41.5 dB, with more than 80% of the attenuation arising from absorption, as confirmed by S-parameter analysis. AI-assisted image segmentation (U-Net architecture) quantified an ~80% reduction in CNT agglomeration and increased interparticle spacing, correlating with the enhanced electrical, dielectric, and thermal properties. The dielectric constant increased from ~2.3 in neat PP to ~6.0 at 5 wt.% CNT with low dielectric loss (tan δ < 0.02), while thermal conductivity improved by ~75%. Tensile strength and modulus increased up to 3 wt.% CNT with a moderate loss in ductility. The combination of dual CNT functionalization, scalable melt processing, and AI-based dispersion quantification provides a reproducible approach for designing lightweight, conductive, and EMI-shielding polyolefin nanocomposites for electronic, automotive, and aerospace applications.