Reactive Blending of <scp>PA6</scp> / <scp> Al ₂ O ₃ </scp> / <scp>CNT</scp> Composites: Synergistic Enhancement of Thermal Conductivity and Tribological Performance

ABSTRACT In this study, high‐performance thermally conductive polyamide 6 (PA6) composites synergistically filled with spherical aluminum oxide (Al 2 O 3 ) and one‐dimensional carbon nanotubes (CNTs) were prepared via reactive blending and compared with those prepared by conventional melt blending. The experimental results showed that at Al 2 O 3 and CNT loadings of 48 and 2 wt%, respectively, the thermal conductivity of the composites reached 0.85 W m −1 K −1 , representing a 240% improvement over neat PA6 and superior performance compared to melt‐blended samples with identical compositions. This performance enhancement was attributed to the ability of reactive blending to achieve uniform dispersion of Al 2 O 3 and good dispersion of CNTs even at high filler loadings, effectively suppressing filler agglomeration and defect formation while constructing more continuous thermal conduction networks. Parallel–series (P‐S) model analysis verified the superior thermal network connectivity of reactively blended samples, and LED heat dissipation tests demonstrated that the material could reduce LED surface temperature by 18.6°C. The reactive blending approach significantly enhanced the tribological properties of PA6/Al 2 O 3 composites compared to the traditional melt blending method. The rbPA6/Al 2 O 3 /2CNT composite exhibited superior performance with a coefficient of friction of 0.35, representing a 58.8% reduction compared to the melt‐blended mbPA6/Al 2 O 3 . Most impressively, the wear rate was reduced to 7 × 10 −5 mm 3 /(N m), a remarkable 70.4% reduction compared to the melt‐blended mbPA6/Al 2 O 3 . The excellent thermal conductivity facilitated rapid dissipation of frictional heat, further enhancing the wear resistance of the material. This study provides an effective strategy for designing high‐performance thermally conductive composites based on the synergistic effects of multiscale fillers.