Reactive Blending of PA6/Al2O3/CNT Composites: Synergistic Enhancement of Thermal Conductivity and Tribological Performance

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. Highlights Reactive blending enables uniform dispersion at high filler loadings. Thermal conductivity increases by 240% compared to neat PA6. Friction coefficient is reduced by 58.8% with 2 wt% CNTs. P-S model validates enhanced thermal network connectivity. High thermal conductivity enhances wear resistance synergistically.