Flame Retardance and Smoke Suppression of CFA/APP/LDHs/EVA Composite

A new intumescent flame-retardants (IFR) system including the charing-foaming agent (CFA), ammonium polyphosphate (APP) and modified-layered double hydroxides (LDHs) with different transition metals (Ni, Co, Cu) were used in the ethylene vinyl acetate (EVA) matrix. Both the limiting oxygen index and the vertical burning tests indicate that the CFA/APP system and LDHs have significant synergistic flame retardant effects. The morphology of combustion residues indicates that the many pores of residues can prevent the melt dripping. The thermal analysis shows that the flame retardants obviously enhanced the thermal degradation temperature of ethylene-based chains of the composites. The cone calorimeter test reveals that the CO2 and combustion residues have an important influence on the reduction of heat release rate (HRR), the smoke production rate (SPR), the production rate and the mean release yield of CO. The composite containing Cu (ELDH-Cu) delivers an 82% reduction in peak heat release rate, while ELDH-Ni has the best CO suppression among all composites. This work not only confirms the flame retardance and smoke suppression of CFA/APP/LDH/EVA, but also provides an effective method for producing new flame retardants and smoke suppressants.