With the increasingly extensive application in modern industries, demand for multifunctionality and performance for epoxy resin (EP) is becoming increasingly stringent. This study develops a hybrid material (B-MTP@CoCu) by in situ growth of cobalt–copper layered double hydroxides on polyphosphazene covalent triazine, which can be uniformly incorporated into the EP matrix, imparting simultaneous improvements in flame retardancy, smoke suppression, and mechanical strength. The EP composite with as low as 3 wt % B-MTP@CoCu is able to achieve a V-0 rating in a UL-94 vertical burning test. The peak heat release rate (pHRR), total heat release (THR), total smoke production (TSP), and peak CO production (pCOP) for the composite with an additive amount of 5 wt % are markedly reduced by 52.5%, 35.5%, 37.1%, and 53.4% respectively. The synergistic effect between polyphosphazene covalent triazine and dual post-transition-metal catalytic centers significantly promotes char formation, which serves as an effective physical barrier during combustion. Moreover, the abundant hydroxyl groups in B-MTP@CoCu enable strong interfacial adhesion to the EP matrix, thereby enhancing its mechanical performance, with tensile and impact strength enhanced by 49.5% and 35.2%, respectively. This work balances the flame retardancy and mechanical strength of the material, providing a potential pathway for fabrication of high-performance EP composites.
Yu et al. (Mon,) studied this question.