Combustion Characteristics and Synergistic Effect of Halogen-Free Flame-Retarded EVA/Hydrotalcite Blends with Expandable Graphite and Fumed Silica

The synergistic effect of hydrotalcite with EG and fumed silica in halogen-free, flame-retardant EVA blends have been studied by limiting oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), and TGA. The EG is a very effective synergist in raising LOI and reducing the heat release rate (HRR) and SEA of the blends. The UL 94 tests show that samples with 2–15 wt% EG can exceed the V-0 rate. The CCT data show that 15 wt% higher expansible ratio EG shows maximum decreases for the pk-HRR and av-SEA values of the EVA/hydrotalcite blends. The fumed silica have no obvious synergistic effects with hydrotalcite.