Synergistic flame retardant effect of melamine in ethylene-vinyl acetate/layered double hydroxides composites

Mg-Al-Fe ternary layered double hydroxides (LDHs) were synthesized based on Bayer red mud by a calcination-rehydration method, and characterized by X-ray diffraction (XRD) and thermogravimetric analysis (TG). The synergistic effects between melamine and LDHs in ethylene-vinyl acetate (EVA) composites were studied using limiting oxygen index (LOI), UL 94, cone calorimeter test (CCT), smoke density test (SDT), and thermogravimetry-fourier transform infrared spectrometry (TG-IR). Though melamine decreases the LOI values of EVA/LDHs/melamine composites, a suitable amount of melamine can apparently improve UL 94 rating; the composite with 45 % LDHs and 5 % melamine can pass UL 94 test. The CCTs results indicate that heat release rates (HRR) of EVA/LDHs/melamine composites decreased in comparison with that of EVA/LDHs composites. The SDT results show that melamine is helpful to smoke suppression. The TG-IR data show that the ternary composites have a higher thermal stability than that of the binary composites.