Filtern
Erscheinungsjahr
- 2006 (3) (entfernen)
Dokumenttyp
- Zeitschriftenartikel (1)
- Beitrag zu einem Tagungsband (1)
- Vortrag (1)
Schlagworte
- Nanocomposites (2)
- Cone Calorimeter (1)
- Cone calorimeter (1)
- Fire retardancy (1)
- Flame retardance (1)
- Flammability (1)
- Intumescence (1)
- Organoclay (1)
- Red Phosphorus (1)
Eingeladener Vortrag
- nein (1)
The exploration of condensed phase mechanisms such as charring and intumescence has been pushed forward in the last decades, since it is believed that focusing on these concepts will bring materials closer to an efficient and ecologically friendly fire retardancy. They promise to concentrate efficient fire retardancy at the key position between pyrolysis zone and gas phase. Examples of residue/char forming and intumescent materials are used to illustrate the influence of mass and heat barrier effects on the fire behavior of materials and general results are presented. A comprehensive understanding of the mechanisms and structure-property relationships in fire retardancy is presented.
Barrier formation and increasing the melt viscosity are addressed as the two main general fire retardancy mechanisms of polymer nanocomposites. They result in specific impacts on fire properties that consequentially cause varying flame retardancy efficiency in different fire tests. The barrier formation retards mainly flame spread (peak of heat release rate) in developing fires, but does not reduce fire load (total heat evolved), ignitability or flammability (limiting oxygen index, UL 94). Furthermore, this flame retardancy effect increases with increasing irradiation and vanishes with decreasing irradiation. The increased melt viscosity prevents dripping, which is beneficial or disadvantageous depending on the fire test used. In some test, it become the dominant influence, transforming self-extinguishing samples into flammable materials or causing wicking. Advantages and the limits are sketched comprehensively for exploiting the main general fire retardancy mechanisms of polymer nanocomposites. It is concluded that barrier formation and changing the melt viscosity in nanocomposites are not sufficient for most applications, but must be accompanied by additional mechanisms in special systems or in combination with other flame retardants.