Phytochemical <scp>COF</scp>‐Modified Magnesium–Aluminum Hydrotalcite for Improving Flame Retardancy and Mechanical Properties of Epoxy Resins

ABSTRACT The high flammability and fume toxicity of epoxy resins (EP) represent the most significant impediments to their broader utilization. In this study, we synthesized a new multifunctional organic–inorganic hybrid flame retardant (PA‐COF@LDH) rich in phosphorus and nitrogen through solvothermal intercalation of COF into Mg/Al‐LDH and subsequent modification with phytic acid (PA). The incorporation of 4 wt% PA‐COF@LDH resulted in EP composites achieving a V‐0 level of UL‐94 with an LOI of 27.1%. The PHRR, THR, and TSP exhibited reductions of 48.29%, 48.32%, and 57.04% compared to EP. The flame retardancy index value reached 4.94, which is classified as “good.” This can be due to the collaboration effect of the coherent and vapor phases. Furthermore, tensile strength and break elongation of EP/4wt%PA‐COF@LDH were enhanced by 18.1% and 32.6%, respectively.