Flame retardancy of nanocomposites - from research to technical products

Flame-retardant nanocomposites are synthesized by melt-blending ethylene-vinyl acetate copolymers with modified layered silicates as nanofillers. Thermogravimetric analysis performed under air demonstrates a clear increase in the thermal stability of the layered silicate-based nanocomposites. The cone calorimeter is used to investigate fire hazards. The nanocomposites cause a large decrease in the peak of heat release rates. Char formation is the main important factor for the improvement of flame retardancy and its function is outlined. Further improvements of the flame retardancy by combinations of nanofillers and traditional flame-retardant additives based on metal hydroxides are also studied. The nanocomposites based on nanofillers and aluminum trihydrate can be used as very efficient systems for flame-retardant cables. The corresponding results are outlined for a coaxial cable fulfilling the UL 1666 riser test.