Silver Nanoparticle Decorated Boron Nitride for Reducing Interfacial Thermal Resistance in Thermal Conductivity Epoxy Resin Composite

ABSTRACT The thermal conductivity of polymer composite is often constrained by the discontinuous structure of filler networks within the matrix and the high thermal contact resistance at filler interfaces. In response to these limitations, this study proposes a novel method for reducing interfacial thermal resistance by creating silver nanoparticle “bridges” through the deposition of silver onto filler surfaces. In this work, boron nitride (BN) hybrids modified with silver nanoparticles (BN‐Ag) were synthesized via the in situ reduction of silver ions. A continuous BN‐Ag framework was constructed using a sacrificial template method, followed by the infiltration of epoxy resin to produce an epoxy resin composite. At a filler content of 42.8%, the thermal conductivity of the composite increased from 1.36 Wm −1  K −1 for BN fillers to 2.57 Wm −1  K −1 for Ag nanoparticle‐modified BN fillers, representing an improvement of 89%. The Foygel model was employed to fit the thermal conductivity data, revealing that the incorporation of silver nanoparticles effectively reduced the contact thermal resistance between fillers. Furthermore, the electrical insulating properties of the composite were preserved, making this design approach highly promising for the development of thermally conductive and electrically insulating polymer composites suitable for electronic applications.