Construction of a synergistic flame retardant SiO2/CoNi-DH-PA for enhancing the fire safety of epoxy resin

In view of the problem that epoxy resin cannot achieve effective flame retardancy, smoke and toxic gas suppression functions in fire, and poor interface compatibility with flame retardants, a coreshell structure with SiO 2 as the nucleus was designed, and a new multi-component flame retardant was prepared by introducing Ni and phytic acid using metalorganic frameworks (MOFs) as precursors. After mixing and curing with epoxy resin, the SiO 2 /CoNi-DH-PA/EP was obtained. With only 5% SiO 2 /CoNi-DH-PA added, the peak heat release, total smoke production, and total CO production of epoxy resin composites are reduced by 63.72%, 31.88%, and 63.74%, respectively, and the residue yield increased from 15.05% to 24.40%. It has been verified that SiO 2 , Co-Ni bimetallic ions and phytic acid have synergistic effects, which can induce and catalyze the formation of a complete and dense carbon layer. This significantly reduces the heat release, smoke, and toxic gas production, thereby reducing the fire hazard of epoxy resin. Additionally, the SiO 2 /CoNi-DH-PA/EP ensures good mechanical properties.