Flame retardant decabromodiphenyl ether

Stapleton, H. M., Alaee, M., Letcher, R. J., Baker, J. E. (2004) Debromination of the flame retardant decabromodiphenyl ether by juvenile carp (Cyprinus carpio) following dietary exposure. Environ. Sci. TechnoL, 38 112-119. 

See E Van den Steen, A Covad, VL Jaspers, etal. 2007. Accumulation, tissue-specific distribution and debromination of decabromodiphenyl ether (BDE 209) in European starlings (Sturnus vulgaris). Environmental Pollution HM Stapleton, M Alaee, RJ Letcher and JE Baker. 2004. Debromination of the Flame Retardant Decabromodiphenyl Ether by Juvenile Carp (Cyprinus carpio) following Dietary Exposure. Environmental Science and Technology 38 112-119 and HM Stapleton, B Brazil, RD Holbrook, et al. 2006. 

In an unprecedented step, the European Parliament has voted to ban two chemicals for which risk assessments are still pending. The chemicals, octabromodiphenylether and decabromodiphenyl ether, were lumped together with penta-BDE during a debate on the EC s proposed ban on that chemical, which is based on a completed risk assessment. All three chemicals are used as flame retardants. Parliamentarians backed the call to extend a ban on penta-BDE to octa-BDE, which is used in office equipment and domestic electrical appliances, by mid-2003. It is claimed that initial results of the ongoing risk assessments already indicate that the chemical is an environmental and public health hazard. MEPs have set a 2006 deadline for banning deca-BDE, adding that the ban should not come into force if the final results of the risk assessment show that deca-BDE is harmless. EUROPEAN PARLIAMENT... 

McKinney MA, Dietz R, Sonne C, De Guise S, Sklmisson K, Karlsson K, Stemgrimsson E, Letcher RJ (2011) Comparative hepatic microsomal biotransformation of selected PBDEs, including decabromodiphenyl ether, and decabromodiphenyl ethane flame retardants in Arctic marine-feeding mammals. Environ Toxicol Chem 30 1506-1514... 

Decabromodiphenyl ether (BDE-209) is a major industrial product from the polybrominated diphenyl ethers used as flame retardants derivatives of this product have been detected in the environment. After exposure to the land surface, these contaminants adsorb on soil materials and may reach the atmosphere as particulate matter these particulates are subsequently subject to photolytic reactions. In this context, Ahn et al. (2006) studied photolysis of BDE-209 adsorbed on clay minerals, metal oxides, and sediments, under sunhght and UV dark irradiation. Dark and light control treatments during UV and sunlight irradiation showed no disappearance of BDE-209 during the experiments. Data on half-lives and rate constants of BDE-209 adsorbed on subsurface minerals and sediments, as determined by Ahn et al. (2006) and extracted from the literature, are shown in Table 16.6. 

The traditional halogen fire retardants used in styrenic copolymers are decabromodiphenyl ether and octabromodiphenyl ether, tetrabromobisphenol A, bis(tribromophenoxy) ethane, ethylene bis-tetrabromophthalimide, and chlorinated paraffins. Actually the octabromodiphenyl ether has been banned on precautionary principles, as will be explained below. The fire-retardant capabilities of the more effective halogen-containing compounds are in line with the quantity of halogen in the final polymer blend, with consideration for the use of synergists. Thus, the practical utility of these flame-retardant compounds (once the issue of degradation temperature is resolved) is often based on their ability to be blended into the polymer and to not substantially affect the physical properties of the polymers. 

Tetrabromobisphenol A is used in epoxy resins especially for glass fiber reinforced used in printed circuit board. Nonreactive compounds such as tetrabromophatalate ester, bis(tribromophenoxy) ethane, and decabromodiphenyl ether are also used. The use of synergists, such as antimony oxide, reduces the quantity of brominated flame retardant necessary but decreases the electrical properties required. 

Additive flame-retardant compounds include brominated epoxy resins, chlorinated hydrocarbons, decabromodiphenyl ether, and pentabromodiphenyl ether. Where transparency is not important, antimony oxide can be used as a synergist to reduce the amount of halogen required. 

Halogenated compounds such as bis(alkyl ether)tetrabromobisphenol A or decabromodiphenyl oxide (DECA) may be used as flame-retardants for polyolefin foams, eventually using antimony oxide, metal oxides, boric acid salts, and metal hydroxides as synergist.92 For example Weil and Levchik93 reported that using suitable amounts of DECA and Sb203, polyethylene foams rated UL94 HF-1 are obtained. 

BDE-154 is a component of the commercially available octa-BDE, which is a complex mixture consisting typically of 0.5% pentabromodiphenyl ether isomers, 12% hexabromodiphenyl ether isomers, -45% heptabromodiphenyl ether isomers, 33% octaBDE isomers, 10% nonabromodiphenyl ether isomers and 0.7% decabromodiphenyl ether. It is used as a flame retardant in plastics for electrical and electronic equipment. 

Decabromodiphenyl ether (decaBDE) was recognized as safe, with no need for risk rednction measnres both in the United States and Europe [9], though CDC lists it as a possible human carcinogen. Currently, under the investigation by EU are the following flame retardants TBBPA (tetrabromobisphenol-A), HBCD (hexabro-mocyclododecane), TCEP [tris(2-chloroethyl)ethyl)phosphate], TCPP [tris(2-chloropropyOphosphate], TDCP [tris(2-chloro-l-(chloromethyl)ethyl) phosphate],... 

PBDEs are a class of 209 chemicals that are distinguished by the average number and arrangement of bromine atoms in the molecule—ranging from one bromine atom (monobromodiphenyl ether or monoBDE) to ten bromine atoms (decabromodiphenyl ether or decaBDE). Until recently, the PBDE flame retardant formulations on the market were pentaBDE (five bromine atoms), octaBDE (eight bromine atoms), and decaBDE. PentaBDE and octaBDE were voluntarily removed from the market in 2003 (pentaBDE) and 2004 (octaBDE) by the manufacturer, Chemtura (formerly Great Lakes Chemical), when it became clear that these chemicals were targeted for elimination in Europe and certain states in the US. 

To test the Green Screen we evaluated three flame retardants that currently meet performance criteria for use in the external plastic housing of televisions (TVs). With the European Union restricting decabromodiphenyl ether (decaBDE) in electronics and with similar legislative initiatives under consideration at the state level in the United States, a recurring question emerges are alternative flame retardants safer than decaBDE from the perspective of human and environmental health and safety ... 

Brominated diphenyls and brominated diphenylethers-for instance, octabromodiphenyl ether (melting point 200°C-290°C) and decabromodiphenyl ether (melting point 290°C-310°C)-have gained great significance. Possessing excellent heat stability, they are excellent flame retardants for those thermoplastics that have to be processed at high temperatures, such as linear polyesters and ABS. 

In the past, polyethylenes were generally flame-retarded with chloroparaffins and antimony trioxide. Frequently PVC or chlorinated polyethylene was also added. Nowadays cycloaliphatic (hexabromocyclododecane) and aromatic bromine compoimds such as polybromodiphenyl ethers, and in particular decabromodiphenyl ether are used. Antimony trioxide is also used here as a synergist. 

The largest volume brominated flame retardant, accounting for about half the market is tetrabromobisphenol-A (TBBA), used in printed circuit boards. The second largest, taking about 10% of the market, is decabromodiphenyl ether, widely used in casings for TVs and computers. Mixtures of polybrominated diphenyl ethers are also found in treated furniture. A third major FR is hexabromocyclodecane, used primarily in polystyrene foam and also in textiles. 

Decabromodiphenyl oxide - bro-(i)mo-(i) di- fe-n l ak- Sld (deca-bromodiphenyl either) n. Diphenyl ether in, which all ten phenyl hydrogens have been replaced by bromine, containing 83% bromine. The commercial product, a free-flowing white powder, is much used as a flame retardant in high-impact polystyrene and structural foam, usually with synergistic antimony oxide. Typical would be 12% decabromodiphenyl oxide and 4% antimony oxide in the resin See image). 

Decabromodiphenyl Etherf 1163-19-5]. This is the second largest bromi-nated flame retardant, and is used in HIPS, textile backcoating, and in polyoleflns, generally together with antimony oxide. It is made, as are the other members of this series, by bromination of diphenyl ether and is commercially available by Albemarle as SAYTEX 102, Great Lakes Chemical as DE-83, and Dead Sea Bromine (DSBG) as FR-1210. In view of the large volume and multiple producers, it is priced favorably. The structure is as follows ... 

Decabromodiphenyl ether is a solid, melting at about 304-309°C, substantially insoluble in water, and with negligible vapor pressure. In contrast to the lower brominated diphenyl ethers, it has only rarely been found as an environmental pollutant and is low in toxicity. Risk studies conducted in the United States and the European Union (33,35) indicate a low degree of risk in the use of this flame retardant. It is the major flame retardant used in high impact polyst5Tene (HIPS) with antimony oxide, and has substantial use in polyolefin wire and cable as well as electrical parts made of other plastics such as polyamides and thermoplastic polyesters. 

Broad Studies of Flame Retardants. Several broad studies of health, safety, and environmental factors of flame retardants have been published by public agencies. A critical review by a US government-appointed toxicology panel was conducted to facilitate CPSC regulations on flammability of furniture upholstery (145). The panel found ammonium polyphosphate, alumina trihydrate, zinc borate, hexabromocyclododecane, decabromodiphenyl ether (oxide), PYKOVATEX CP, and THPC to be usable with minimum risk on residential furniture even with worst-case assumptions. Antimony trioxide, several organophosphates, chlorinated paraffins, and molybdate salts were said to need more exposure studies. 

A study at the University of Surrey sponsored by the UK Department of Trade and Industry weighed health risks (toxicity and exposure) of a wide range of flame retardants vs their benefits (146). This study encompassed aliunina trihy-drate, antimony trioxide, decabromodiphenyl ether, tetrabromobisphenol A, and tris(chloroisopropyl) phosphate, and in general foimd that the benefits ontweighed the risks. 

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