Flame-Retardant Effect of Sepiolite on an Intumescent Flame-Retardant Polypropylene System

Intumescent flame-retardant polypropylene-containing phosphorus and nitrogen compounds were enhanced significantly by adding a small amount of sepiolite as a synergistic agent The flame-retardant polypropylene composite was characterized by limiting oxygen index (LOI), UL-94, the cone calorimeter (CCT), and thermogravimetric analysis (TGA) to study the combustion behavior and thermal stability. The addition of 0.5% sepiolite increased the LOT from 29.8 to 31.8. The addition of sepiolite at a low additive amount appears to be an optimum blend ratio for the low heat release rate, total smoke, and CO2 production. Sepiolite also has a significant improvement in mechanical properties.