ABSTRACT Developing flame‐retardant epoxy resin (EP) with high performance has drawn extensive attention recently due to the growing public concern for fire safety. However, the simultaneous enhancement of flame retardancy and toughness without the sacrifice of mechanical strength and thermal stability is still a challenge for EP. Herein, a novel kind of imidazole‐based reactive flame retardant MD containing P/N/Si was synthesized and applied into EP. The results demonstrated that due to the presence of P/N/Si multiple flame‐retardant elements, incorporating 4 wt% MD could make EP/MD pass UL‐94 V‐0 grade and have a limiting oxygen index (LOI) of 29.7%. Meanwhile, compared with pure EP, the peak heat release rate (PHRR), total heat release rate (THR), peak smoke production rate (PSPR), and total smoke production (TSP) of EP composite containing 4 wt% MD exhibited an obvious reduction of 41.5%, 11.4%, 24.2%, and 12.9%, respectively. Moreover, thanks to the high reactivity of imidazole groups, the MD could participate in the cross‐linking reactions of EP and form strong interfacial interaction between the matrix and flame retardant. Therefore, the mechanical strength and toughness as well as the glass transition temperature of EP/MD composites could be simultaneously and greatly enhanced (tensile strength +30%, flexural strength +35%, impact strength +22%, and T g + 7°C). This work provided a feasible methodology for the fabrication of highly efficient flame‐retardant EP with prominent mechanical and thermal properties.
Zhu et al. (Thu,) studied this question.
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