Abstract
Epoxy resins (EPs) are widely used in various industries due to their high mechanical strength, excellent adhesion, chemical resistance, good electrical insulation, and other properties. However, the use of pure EPs that are easily flammable poses a great risk of fire to human life and property, which has driven the development of efficient additive flame retardants (FRs) to enhance the fire resistance of EPs. Therefore, in this work, three additive FRs were designed and synthesized. An FR PCNOH-CuCo was obtained by synthesizing a polymer PCNOH based on hydroxylated graphitic carbon nitride (GCN) through covalent polymerisation, followed by chelating Co and Cu, showing 47.9%, and 37.5% reductions in peak heat release rate (PHRR) and total heat release (THR), respectively. An FR HCN was synthesized by hybridizing a hypercrosslinked aromatic polymer with GCN through a solvent-free method, showing 41.2% and 38.4% reduction in PHRR and THR, respectively. Then, to overcome the difficulty in experimentally testing countless combinations of additive FRs, an ML model was established based on the structure and addition amount of FRs, with the limiting oxygen index (LOI) as the target. This model successfully guided the design of a FR BDOPO and predicted the variation of the LOI of EP loaded with BDOPO with its addition amount. The feasibility of BDOPO synthesis and the accuracy of the ML model was experimentally validated. Finally, five ML models were established based on the structure and addition amount of FRs, with LOI, time to ignition (TTI), PHRR, THR, and vertical combustion test (UL-94) level as the targets. These models, combined with the guidance on the structure of FRs, were used to design and prepare BDOPO, which then predicted and experimentally validated those properties. The four works offered in this work provide effective approaches to designing FRs for high-performance EP.