Epoxy Composites with Dynamic Bonds and High Thermal Conductivity Based on Heterostructure Boron Nitride

Currently, enhancement of thermal conductivity in epoxy resin composites is mainly achieved by adding fillers with high thermal conductivity. However, due to weak interfacial compatibility, the thermal enhancement effect of the fillers is hampered, and other material properties may be adversely affected. Additionally, traditional epoxy cross-linked networks are incapable of self-healing damage and are nondegradable, which shortens the material lifespan and poses environmental pollution concerns. Aiming to resolve these challenges, the present work designed a one-step comodification process, where boron nitride (BN) was functionalized concurrently with polypyrrole (PPy) and silver nanoparticles to produce the target filler, denoted as MBN. This approach is simple, mild, and efficient. During the reaction, in situ generated PPy improved the compatibility at the BN/resin interface, while the silver nanoparticles collaborated with BN to form a zero-dimensional/two-dimensional synergistic thermal conduction network. Furthermore, by introducing a disulfide bond-bearing curing agent to cure bisphenol A epoxy resin (E51), a dynamic covalent network was constructed within the system. Compared with pure epoxy resin, the E51–30 wt % MBN/1 composite showed a 5.2-fold increase in thermal conductivity, reaching 0.988 W/mK. The material could self-heal 92.8% of scratch damage within 60 min and fully degraded at 80 °C, with the recovered fillers maintaining their intact morphology. This epoxy composite with high thermal conductivity and dynamic bonds demonstrates promising application prospects in thermal management fields.