Effects of ANF/BN composite coating on the thermal conduction properties of meta-aramid paper

An ANF/BN composite coating was constructed on meta-aramid paper. • BN nanosheets created efficient thermal conduction pathways. • Hydrogen bonding enhanced the interfacial interaction between ANF and BN. • The composite paper achieved improved thermal conductivity while maintaining insulation. • The composite paper demonstrated effective heat dissipation in LED applications. Meta-aramid paper (MAP), a critical insulating material in high-power-density electrical equipment, currently faces a severe bottleneck due to the inherent trade-off between high electrical insulation and low thermal conductivity. In this work, a high-performance composite thermal conduction coating was formulated by uniformly compounding liquid-phase ball-milled, size-controlled boron nitride (BN) or its nanosheets (BNNSs) with aramid nanofibers (ANFs). This coating was then directly applied onto the surface of a MAP substrate, followed by hot-pressing to construct a dense thermal-conduction network with preferential in-plane packing of BN platelets. Within the coating architecture, ANFs acted as an efficient nanoscale binder, providing excellent wrapping and interfacial interlocking to firmly anchor the BN or BNNSs on the MAP. The regulation of BN lateral size together with the preferential in-plane packing of the BN platelets facilitates the formation of more continuous in-plane thermal-conduction pathways. Experimental results demonstrated that the composite paper exhibited an outstanding in-plane thermal conductivity of 3.25 W·m −1 ·K −1 , representing a remarkable ~378% enhancement over pristine MAP. Download: Download high-res image (223KB) Download: Download full-size image