1. Improve strength and elongation. Epoxy resin is a basic resin material. Adding fumed silica to epoxy resin is completely different from epoxy resin-based composite materials added with coarse-crystalline silica (white carbon black, etc.) in structure. Coarse-crystalline SiO2 is generally added as a reinforcing agent, and it is mainly distributed between the chains of polymer materials. Fumed silica has strong activity due to its serious surface coordination deficiency, large specific surface area, and surface oxygen deficiency. It is easy to form bonds with the oxygen of epoxy ring molecules, thereby increasing the bond strength between molecules. At the same time, some fumed silica particles are still distributed in the gaps of polymer chains. Compared with coarse-crystalline SiO2 particles, they show high rippling properties, thereby greatly improving the strength, toughness, and ductility of epoxy resin materials added with fumed silica.