Tailoring polyamide 66 nanocomposites with plasma-engineered carbon nanotubes for advanced mechanical and thermal properties

In this study, high-performance polyamide 66 (PA66) nanocomposites were developed through in-situ polymerization with plasma-engineered carbon nanotubes (CNTs). To achieve uniform dispersion and strong interfacial bonding, CNTs surfaces were functionalized via low-temperature plasma treatment, introducing reactive isocyanate groups. Structural analyses confirmed that the plasma-treated CNTs (pCNTs) were more uniformly dispersed than their untreated counterparts (nCNTs), and that urea bonds formed at the polymer–filler interface contributed to enhanced interfacial adhesion. As a result, the PA66/pCNTs nanocomposites exhibited remarkable improvements in mechanical properties (e.g., 87 % increase in Young's modulus, 50 % increase in tensile strength) and thermal resistance (e.g., 20 °C increase in decomposition temperature), even at very low CNTs loadings (≤0.05 wt%). These results demonstrate that plasma-engineered CNTs improve filler dispersion and interfacial bonding, leading to enhanced mechanical and thermal properties of PA66 nanocomposites, which could enable advanced multifunctional applications. • PA66 nanocomposites via in-situ polymerization with plasma-treated CNTs. • Plasma treatment adds isocyanate groups, boosting CNTs–PA66 compatibility. • Uniform CNTs dispersion achieved through in-situ polymerization. • Covalent bonds form at CNTs–PA66 interface, enhancing adhesion. • Strong mechanical and thermal improvements at ultralow CNTs loadings.