The effect of nanometals on the flammability and thermooxidative degradation of polymer materials

It was found that finely dispersed metals (nanometals) at low addition (less than or equal to1% wt.) increase flammability of neat polypropylene in spite of strong enhancement of char yield. The nanometals do not seriously affect flammability of neat epoxy resins. On the other hand, it was shown that the nanometals are very efficient co-additives in combination with some phosphorus containing fire retardants in both polypropylene (thermoplastic) and epoxy resin (thermoset). At the specific content of the metals, a sharp maximum is observed on the dependence of oxygen index on concentration of fire retardant additives which proves occurrence of strong synergistic effect. Thermal analysis and characterization of solid residues allowed to approach to the mode of fire retardant action of the nanometals..