Synergistic Strategy to Break Trade-Off in Thermal-Mechanical Properties via ZIF-8 Enhanced Epoxy Nanocomposites

Conventional epoxy composites comprising nanosized silica (SiO2) fillers are encumbered by the inherent trade-off between their stiffness and toughness, which hinders their applications in high-performance scenarios. Herein, zeolitic imidazole framework-8 (ZIF-8) was integrated into epoxy/SiO2 nanocomposites as a curing agent, forming robust covalent bonds that improve thermal–mechanical properties and toughness of epoxy/SiO2 nanocomposites even at low SiO2 filler loadings. Owing to the anchoring effect between ZIF-8 and epoxy resin and strong interfacial bonding strength, the coefficient of thermal expansion of epoxy nanocomposites considerably decreases to 52.3 ppm °C–1, with a filler loading of 28 wt %. Their tensile behavior is strengthened at room and high temperatures due to the synergistic action of nanofillers. Furthermore, the storage modulus and fracture toughness at high temperatures also increase by up to 238 and 41.7%, respectively, showing a substantial and remarkable enhancement in these properties. This study reports a method for preparing multifunctional epoxy composites for electrical packaging and offers insights into the interface–property relationships.