Enhancement of thermal stability and flame retardancy of ethylene vinyl acetate/magnesium hydroxide composite by carbon black

Nano-sized carbon black (CB) was introduced to ethylene vinyl acetate/magnesium hydroxide (EVA/MH) composite by melt compounding and the EVA/MH/CB ternary composites were investigated in terms of their thermal, flame retardant, mechanical, and electrical properties. The results indicate that the introduction of MH and CB has no impact on thermal degradation mechanism of EVA, but inhibits its degradation substantially. The presence of CB can hinder thermo-oxidative degradation and increase thermal stability of the EVA/MH composite significantly. The addition of CB increases the flame-retardant efficiency of MH effectively. The EVA/MH/CB composite with 3.6% CB can achieve V-0 rating and its peak heat release rate is 23% smaller than that of the EVA/MH composite, which only achieves V-2 rating in UL-94 test. The improvement in flame retardancy happens in condensed phase. On the whole, the introduction of proper CB can enhance the thermal and flame-retardant properties of EVA/MH composite considerably without damaging its mechanical and electrical performances. This work provides a simple and cost-effective method to further increase the properties of EVA/MH composite for wire and cable industry.