Brominated fire retardants

At present, there are studies underway to determine the toxicological characteristics and effects on hygiene of a number of halogen-containing FRs. Work has been published in Sweden su esting the possibility of environmental accumulation resulting in the presence of these materials in the food chain from fish to humans (breast milk) [94]. The use of some brominated FRs such as polybrominated 

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This symposium addressed several important issues in bromine chemistry. A major part has been devoted to stereochemistry and mechanism of electrophilic bromination of olefins. Other topics included new selective methods of bromination and oxybromination, brominations in presence of solid supports and catalysts, organobromine compounds as synthons, recent developments in brominated fire retardants and toxicological and environmental aspects of brominated compounds. 

The challenge was to avoid the use of hazardous brominated fire retardants such as polybrominated biphenyl (PBB) and pentabromodiphenyl ether (PBDE). The first strategy was to replace PBB and PBDE with tetrabromo-bisphenol-A (TBBA). This has a much lower toxicity, but is still a brominated fire retardant with safety concerns. An improvement... 

Poly-pentabromobenzy1 acrylate Figure 2. Brominated fire retardants. 

Renner R. 2000b. What fate for brominated fire retardants Environ Sci Technol 34(9) 222A-226A. 

Renner, R., 2000. What fate for brominated fire retardant Environ. Sci. Technol. 34, 223A-226A. 

In the case of brominated additives the process is less studied, for decabromodiphenyl oxide, a widely used brominated fire-retardant additive, Sb8OnBr2 is the dominant oxybromide, whereas Sb405Br2 was not detected in measurable amounts. It was assumed that, if this last is formed by bromination of Sb8OnBr2, it eliminates SbBr3 relatively rapidly either by thermal disproportionation or by chemical reaction with decabromodiphenyl oxide.42... 

To improve the fire retardancy of polypropylene, beyond the UL 94 V-2 level, it is necessary to use blends of aromatic bromine fire retardants with antimony trioxide as a synergist. The usual loading is between 35% and 40% fire retardant however, the additional cost may prohibit commercialization. Moreover, the presence of aromatic bromine increases the photooxidation of polypropylene67 69 inactivating hindered amines. To reduce the cost without losing in efficacy the combination of brominated flame-retardant/antimony trioxide system with magnesium hydroxide... 

It is intended to use these properties for the assessment of alternative flame retardants (FRs) (including nanoparticles, phosphates, and inorganic metal oxides) in comparison with brominated fire retardants by quantitatively assessing ... 

Vo, C.V. Boukami, S. Fire resistant styrene polymer foams with reduced brominated fire retardant, US Patent 6579911, assigned to The Dow Chemical Company, 2003. 

During the last decade, environmentalists have fought strongly to ban the use of brominated fire retardants, and already a number of plastics processors have voluntarily switched to non-halogenated ones (such as phosphate esters, aluminium trihydride and magnesium hydroxide fire retardants). Still, there are two contradictory forces in the fire retardant industry, one is the constant push for stronger fire-safety standards, and the other is the move to eliminate flame-retardants seen as persistent, bioaccumulative or toxic [19]. 

Figure 9.14 GRP fume scrubber, dismantled after 8 years of trouble free service. The resins used were vinyl esters, including a brominated fire retardant grade. Dimensions 11m high, 5m diameter...

An unaccelerated, brominated, fire retardant epoxy vinylester base resin containing 3% antimony trioxide. Suitable for cold-press moulding, continuous lamination, pultrusion and filament winding. 

Figure 1.1 compares the flame retardant efficiency of aliphatic brominated flame retardant and aromatic brominated flame retardant. Because the thermal decomposition of the aliphatic flame retardant starts at temperatures below the thermal decomposition of pol5T)ropylene, it shows very good performance in polypropylene. In contrast, because the aromatic brominated fire retardant is significantly more stable, optimum debromination is not achieved at the temperature of decomposition of polypropylene, and this flame retardant shows inferior performance. 

Harper et al. [152] have reported a microscopical study of several brominated fire retarded ABS/ Sb203 formulations. Whereas SEM showed good dispersion of Sb203 regardless of particle size, TEM... 

Many ways have been developed to decrease the inflammability of cured UPRs. The most important method consists of incorporating brominated raw materials or adding brominated fire retardants. The use of brominated compounds, in particular polybrominated diphenyl ether, has been criticized for toxicological reasons [103]. As the source of bromine in UPRs, 2,3-dibromo-2-butene-l,4-diol (Scheme 19) ... 

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