Multi-element organic-inorganic flame retardants for enhancing the flame retardancy, reducing smoke and toxicity of epoxy resins

Epoxy resins (EP) have been commonly used, but their poor flame retardant properties have prevented their widespread use. In order to improve the flame retardant properties of EP, an organic-inorganic composite flame retardant (HKDC) containing multi-element P/N/Si was successfully synthesized in this work using a typical aldehyde amine condensation reaction. This flame retardant utilizes the synergistic effect of multiple elements to simultaneously perform the flame retardant function of each element, and it can achieve excellent flame retardant effect by using low addition amount in EP. At the same time, this flame retardant can not only reduce the migration of molecules through the structure of inorganic substances, but also the C = C reaction in EP can form large molecules and increase the compactness with the EP matrix. The flame retardants were then quantified by measuring their flame retardant properties, combustion behavior and thermal stability. When the flame retardant HKDC is added, the flame retardant performance of EP is improved and the vertical combustion test achieves a V-0 rating. Most importantly, the addition of flame retardant HKDC effectively suppressed the toxic gas and smoke emissions of EP, with TSP values much lower than those of pure EP, and CO and CO2 emissions were suppressed.