Three‐dimensional skeleton assembled by nickel foam/silicon carbide as filler in polyurethane composites with high thermal conductivity and electrical insulation

High thermally conductive polymer composites have garnered significant attention due to their exceptional performance, given the ever‐decreasing size of electronic devices and the rise in power densities. Herein, a new three‐dimensional (3D) thermal conductivity network structure has been successfully prepared using double fillers of nickel foam (NF) and modified silicon carbide particles (KSiC). The study compared the effect of different filler contents on the thermal conductivity of composites. Compared to conventional composites, those based on 3D filling networks have significantly improved thermal conductivity. The thermal conductivity of the NF/KSiC/PU composite containing 50 wt% KSiC was 1.18 Wm−1 K−1, exceeding the cumulative thermal conductivity of the NF/PU and KSiC/PU 50 wt% composites, and 637.5% greater than that of neat PU. Meanwhile, the synthesized NF/KSiC/PU composite maintained a high electrical resistivity above 1012 Ω·cm and good mechanical properties. This approach might offer novel solutions for developing high‐quality packaging materials for advanced electronic devices with exceptional thermal and mechanical properties. Highlights Using SiC and NF Constructs a dual filler network. The dual filler thermal conductivity network can generate synergistic effects. Improving thermal conductivity compared to original polyurethane. Maintaining a high electrical resistivity and good mechanical properties. In this work, a new three‐dimensional thermal conductivity network structure has been successfully prepared using double fillers of nickel foam (NF) and modified silicon carbide particles (KSiC). The thermal conductivity of the NF/KSiC/PU composite could reach 1.18 Wm‐1K‐1.