In thermoplastics, fumed silica can improve the toughness of plastics. After it is added to plastics, it can increase the toughness of the material without weakening the rigidity of the material, and even increase the rigidity of the material.


In thermosetting plastics, the addition of fumed silica to epoxy resin can significantly improve its brittleness, which can overcome the defects of material rigidity and strength reduction caused by toughening of elastomers, and achieve the purpose of strengthening and toughening.
In plastics, silica can also be used as a flame retardant. Because the fumed silica increases the strength of the carbon-silicon layer through the physical process in the condensed phase, it can prevent the transfer of heat and substances during combustion.