Recyclable Technology of Thermosetting Resins for High Thermal Conductivity Materials Based on Physical Crushing

Epoxy resin, characterized by prominent mechanical and electric‐insulation properties, is the preferred material for packaging power electronic devices. Unfortunately, the efficient recycling and reuse of epoxy materials with thermally cross‐linked molecular structures has become a daunting challenge. Here, we propose an economical and operable recycling strategy to regenerate waste epoxy resin into a high‐performance material. Different particle size of waste epoxy micro‐spheres (100–600 μm) with core‐shell structure is obtained through simple mechanical crushing and boron nitride surface treatment. By using smattering epoxy monomer as an adhesive, an eco‐friendly composite material with a “brick‐wall structure” can be formed. The continuous boron nitride pathway with efficient thermal conductivity endows eco‐friendly composite materials with a preeminent thermal conductivity of 3.71 W m −1 K −1 at a low content of 8.5 vol% h‐BN, superior to pure epoxy resin (0.21 W m −1 K −1 ). The composite, after secondary recycling and reuse, still maintains a thermal conductivity of 2.12 W m −1 K −1 and has mechanical and insulation properties comparable to the new epoxy resin (energy storage modulus of 2326.3 MPa and breakdown strength of 40.18 kV mm −1 ). This strategy expands the sustainable application prospects of thermosetting polymers, offering extremely high economic and environmental value.