Decoupling Rheological and Electrical Percolation Thresholds in CNT ‐Reinforced Polypropylene Nanocomposites: A Framework for Tunable Multifunctionality

ABSTRACT This study quantifies the dual percolation behavior of carbon‐nanotube (CNT)–reinforced polypropylene (PP) by pairing dynamic oscillatory rheometry, impedance spectroscopy, and scanning electron microscopy (SEM) across matched loadings. A rheological (stress‐bearing) network emerges at ~0.30 wt% CNT, evidenced by a low‐frequency G′ plateau, while electrical percolation occurs at ~0.40 wt%, producing a rise of ≈6 orders of magnitude in DC conductivity. All datasets are reported as discrete points with mean ± SD ( n ≥ 3). Fitting σ ( ϕ ) to a percolation law, σ = σ 0 ( ϕ − ϕ c ) t for ϕ ≥ ϕ c , yields the critical loading ( ϕ c ) and exponent ( t ), thereby decoupling stress‐bearing connectivity from charge transport. SEM corroborates network densification across the percolation window. The resulting design map—insulating → rheologically percolated (dielectric) → electrically percolated (conductive)—enables independent tuning of mechanical reinforcement and electrical functionality for applications ranging from structural dielectrics to sensing and EMI shielding. The framework provides a practical route to structure–property control in CNT‐based macromolecular systems under scalable processing.