Fire/flame retardants materials

Another well-known measurement for determining the burning behavior of a material is the LOI, which gives the concentration of oxygen in the air necessary to perform a fire. Flame-retarded materials should reach LOI values of about 32. Figure 25 shows the determined values for LDH-LDPE nanocomposites with different filler loading. 

Most circuit boards are FR-4 boards that meet standards for fire safety by the use of brominated epoxy resins in which the reactive flame-retardant tetrabromobisphenol A (TBBPA) forms part of the polymeric backbone of the resin. Alternative flame-retardant materials are used in only 3-5 per cent of the FR-4 boards, but additional alternative flame-retardant materials are also imder development. Little information exists concerning the potential environmental and human health impacts of the materials which are being developed as alternatives to those used today that are based on brominated epoxy resins. 

These can be inorganic materials such as calcium silicate, mineral wool, diatomaceous earth or perlite and mineral wool. If provided as an assembly they are fitted with steel panels or jackets. These are woven noncombustible or flame retardant materials the provide insulation properties to fire barrier for the blockage of heat transfer. 

This term is used for any additives that allow a polymer to retard a flame, or for any polymer that shows the ability to slow fire growth when ignited. It does not mean noncombustible or ignition resistant—these are very different terms and should not be used to describe a flame-retardant material. A material that is truly noncombustible or ignition resistant either cannot be combusted (no thermo-oxidative decomposition can occur) or cannot be ignited with a particular size... 

Humanity is, by nature, emotional, and emotions on both sides of this issue make progress difficult for new fire safe materials, whether in response to new fire risk scenarios or in response to non-fire-related issues. This last point should make it clear that flame retardancy of plastics is not a simple scientific issue, but one that must take into consideration societal, emotional, and non-fire-related issues to make an acceptable new flame-retardant material in the twenty-first century. 

Other work in this area has been reported in recent years. Of particular note is that of Lyon, which has also been involved in synthesizing inherently flame-retardant materials to improve the fire resistance of aircraft interiors.11 12... 

Castrovinci, A. Lavaselli, M. Camino, G. Recycling and disposal of flame retarded materials. In Advances in Fire Retardant Materials. Horrocks, A. R. Price, D., Eds.., Boca Raton, FL CRC, 2008, pp. 213-232. 

In this chapter, we have discussed recent developments of intumescent flame-retarded materials in terms of reaction and resistance to fire. Research work in intumescence is very active. New molecules (commercial molecules and new concepts) have appeared. Nanocomposites are a relatively new technology in the held of flame retardancy. This technology gives the best results combined with conventional FRs and leads to synergistic effects with intumescent systems. Very promising developments in the synergy aspects are then expected and efforts should be continued in this way. 

Figures 15.8 and 15.9 illustrate examples of how cone calorimeter data can be used in the development of flame-retarded materials. PA 66-GF without Pred showed typical fire behavior for noncharring polymers containing inorganic glass fiber as inert filler,69 when high external heat flux is applied. The shape of the HRR curve is divided in two different parts. In the beginning, the surface layer pyrolysis shows a sharp peak, followed by a reduced pyrolysis rate when the pyrolysis zone is covered by the glass fiber network residue layer. When Pred was added, the PA 66-GF samples were transformed into carbonaceous char-forming materials, which led to a...

Efficient fire protection is also based on the consideration of product or scenario-specific hazards, which may lead to very specific materials development goals. Examples are the combination of impacts, such as vandalism and ignition source for seats in railway vehicles, or a preceding shock wave before the fire impact in navy applications. Some more product-specific phenomena of such kind are related directly to material properties, such as building up an increased risk for pool fires through burning thermoplastic plastics or dripping foams, and thus have become topics in the development of some flame-retarded materials.103... 

PA 66-GF is fairly constant, since the polymer is nearly completely combusted for all irradiances used, whereas the THE decreases most for the flame-retarded material at low irradiance, because the char formation is at the highest level. This effect diminishes with increasing irradiance. In the case of Pred in PA 66-GF, combustion is complete at the highest external heat flux, with or without flame retardant, so the THE is almost the same, but the fire growth index is almost halved. Conversely, at low irradiance, not only is the fire growth index reduced, but the THE is almost halved as well. The change in the fire scenario changes the effectiveness of Pred added to PA 66-GF in two of the most important fire properties. Pred in PA 66-GF works best for low external heat flux. Flammability tests like LOI and, much more important, UL 94, are fire scenarios with low external heat flux. 

Drysdale DD. Fire safety design requirements of flame-retarded materials. In Fire Retardant Materials. Horrocks AR, Price D, Eds. Woodhead Publishing Cambridge, U.K., 2001 chap. 13, pp. 378-397. 

The most important use of bromine today is in making flame retardant materials. Many materials used in making clothing, carpets, curtains, and drapes are flammable, and if a flame touches them, they burn very quickly. Chemists have learned how to make materials more resistant to fires by soaking them in a bromine compound. The compound coats the fibers of the material. The bromine compound can also be chemically incorporated into the material. 

Natural fiber-reinforced polyolefins are commonly apphed to automotive and constmction applications. The most abundantly used additive is fire retardant. Flammability is an important factor that often limits the application of composites to a specified field. Magnesium hydroxide is the most common flame retardant material used in the constmction industry. This filler responds well to surface modifiers and decomposes by an endofliermic reaction that releases water at temperatures close to the polymer degradation temperature as show in Eq. 6.1. Rothon et al. [78] studied the effects of magnesium hydroxide on polypropylene as a flame retarder of 60 % by weight. The smdy found less heat emission at 100 kWm after 6 min of fire exposure compared to filled PP without Mg(OH)2 at 500 kWm. ... 

SorathiaU. Flame retardant materials for maritime and naval applications. In Horrocks AR, Price D, editors. Advances in fire retardant materials. Cambridge Woodhead Publishing 2008. p. 527-72. 

These days all products must satisfy application-specific demands on preventative fire protection. Such demands are best fulfilled technically and economically by the use of flame retardants. These help to limit flame spread and heat release in incipient fires and frequently to prevent fires from starting in the first place. The appropriate type of flame retardant material is determined not only by the required flame resistance standard and the physical dimensions for the particular application but also by the family of polymers used. 

This chapter gives the briefest of outlines of the different flame retardant families and their capabilities in protecting plastics compounds. A more comprehensive review of fire ehemistry and the actions of the different types of flame retardant materials is to be found in the previous edition of this Rapra report, Fire - Additives and Materials , Rapra Technology Ltd., 1995. 

Studies in the US in the past, mainly through the auspices of the National Institute of Standards Technology (and its predecessor. National Bureau of Standards), have shown that the overall costs, in terms of damage, health and environmental considerations, of non-flame retarded TV cabinets, and other consumer items, that are involved in fires is much higher than those associated with a properly formulated and flame retarded material used for the same purposes. 

In 1988, the National Bureau of Standards [now the National Institute of Standards and Technology (NIST)] ran room combustion tests comparing flame retardant with non-flame retardant plastics used in printed wiring boards, television set and business machine enclosures, cables, and upholstered furniture. The results showed that flame retardant materials allow more than a 15-fold longer escape time, 75% less heat release, significantly less smoke, and a lower concentration of toxic gases. Fire retardants decrease toxicity in fires. The effect is due to a decrease in the amount of burning material. ... 

Lefebvre, J. Le Bras, M. Bourbigot, S. Lamellar double hydroxides/polymer nanocomposites a new class of flame retardant material, in M. Le Bras, C.A. Wilkie, S. Bourbigot, S. Duquesne, and C. Jama, Eds., Fire Retardancy of Polymers New Applications of Mineral Fillers. Royal Society of Chemistry, London, 2005, pp. 42-53. 

Each year about 5000 people are killed by fires in Europe and more than 4000 people in the United States. Direct property losses by fires in the United States are roughly 0.2% of the gross domestic product, and the total costs of fires are around 1% of the gross domestic product." Therefore, it is important to develop well-designed flame retardant materials to decrease both fire risks and fire hazards. 

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