Covalently modified graphene and 3D thermally conductive network for PEEK composites with electromagnetic shielding performance

Polyetheretherketone (PEEK) has inferior interfacial compatibility due to its rigid structure. Hence, achieving the desired thermal conductivity (TC) of PEEK composites is challenging. Covalently bonded amino-graphene (NH2-GnPs) and polybenzoxazine (PBZ) can reduce interfacial thermal resistance (ITR). Hybrid NH2-GnPs and multi-walled carbon nanotubes (MWCNTs) were applied synergistically to refine the TC pathways. Additionally, the 3D thermally conductive network was constructed from electrospun NH2-GnPs&MWCNTs/ketimine-biphenyl polyetheretherketone (PEBEKt) and freeze-dried MWCNTs/PEEK@PBZ composites arranged in a sandwich structure. The oriented fillers could improve the heat diffusion network by increasing heat flow conveyance. The optimal in-plane and through-plane TC values were 21.0 and 6.9 Wm−1K−1, respectively, 90 and 29 times those of pure PEEK. The composites also exhibited excellent electromagnetic shielding (80.4 dB, 21.1%), thermal stability, and thermal management capabilities. Consequently, the 3D thermally conductive composites can provide a viable idea for thermal management and electromagnetic shielding materials.