Decabromodiphenyl oxide flame retardant additive

DecabromodiphenylOxide. Decabromodiphenyl oxide [1163-19-5] (decabrom) is the largest volume bromiaated flame retardant used solely as an additive. It is prepared by the bromination of diphenyl oxide ia neat bromine usiag AlCl as a catalyst (32). The bromination may also be carried out ia an iaert solvent such as methylene dibromide [74-95-3] (33). The commercially available grades are >98% decabromodiphenyl oxide with the remainder being the nonabromo species. 

Research sponsored by BFRIP regarding the use of brominated flame retardants shows that there is no evidence that the use of decabromodiphenyl oxide leads to any unusual risk. In addition, a study by the National Bureau of Standards (now National Institute of Science and Technology) showed that the use of flame retardants significantly decreased the ha2ards associated with burning of common materials under reaUstic fire conditions (73). Work ia Japan confirms this finding (74). 

Flame Retardants. Flame retardants are added to nylon to eliminate burning drips and to obtain short self-extinguishing times. Halogenated organics, together with catalysts such as antimony trioxide, are commonly used to give free-radical suppression in the vapor phase, thus inhibiting the combustion process. Some common additives are decabromodiphenyl oxide, brominated polystyrene, and chlorinated... 

It should be mentioned that fire retardant-polypropylene has higher impact energy than polypropylene without HBCD and this improved impact energy resulting from the addition of fire retardant is a rare phenomenon. Usually the addition (15-25%) of low molecular components decreases the high impact properties of plastics although we know that HIPS flame-retarded with decabromodiphenyl oxide (DECA), for example, has almost the same impact energy as non-retarded HIPS (Table 5). 

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. 

The effect of additives, others than plasticizers, on the dynamic mechanical properties of styrene polymers have attracted little attention from researchers. Flame retardants such as l,2-bis(tetrabromophthalimide)ethane, crystalline decabromodiphenyl oxide (DBDPO) and antimony trioxide (Sb203) do not affect the a relaxation of aPS [38,39]. 

Bromine compounds are also used as fire retardants. These compounds are about twice as effective as chlorine compounds on a weight basis, so that significantly lower concentrations are needed. However, bromine compounds are higher in cost than chlorinated compounds and are generally less stable under exposure to heat and light (29). Those compounds containing aromatic bromine are significantly more stable to heat and hydrolysis than the aliphatic type. Examples are decabromodiphenyl oxide (DBDPO), tetrabromobisphenol and tetrabromobisphenol A. A pentabromodiphenyl oxide blend is available for urethane foams and polyesters (34). Aliphatic bromine-type additives are used as flame retardants in plastic foams (polyurethane and polystyrene (33). 

A more complex fire retarding system was used in propylene-ethylene copolymer. This system consists of huntite/hydromagnesite/antimony triox-ide/decabromodiphenyl oxide. Fillers act as effective flame retardants and, in addition, reinforce the copolymer. At the same time, an agent acting in the gaseous phase was needed to reduce the height of flames. A combination of antimony trioxide and decabromodiphenyl oxide plays this role in the system. 

Of the halogenated organics, brominated aromatic compounds are the most extensively used. Decabromodiphenyl oxide or Saytex BT-93 is approved, but poly-(dibromophenylene oxide) is specifically recommended for polyamides. Brominated epoxy resins are also suitable flame-retardants for polyamides. The synergetic partner additive is antimony trioxide in most cases. 

Halogenated additive flame-retardants may also be admixed with the resin. Tetra-bromo-p-xylene, pentabromobenzyl bromide, pentabromoethyl benzene, pentabro-motoluene, tribromocumene, decabromodiphenyl oxide, and brominated epoxy resins are some of the compounds used. 

Brominated hydrocarbons. Brominated hydrocarbons represent the highest dollar volume among all flame retardants used worldwide. The major additive types are decabromodiphenyl oxide (DBDPO) and derivatives of tetrabromobisphenol A(TBA). The major reactive type is TBA itself. Significant amounts of TBA are also used to make additive types. Typically, brominated compoimds are used with a synergist... 

Flame-retardant grades of PBT usually consist of synergistic mixtures of antimony trioxide with various halogenated (brominated) aromatic compounds. A typical recipe for PBT might be 10 wt% decabromodiphenyl oxide and 5 wt% antimony oxide. Recently the trend has been to use polymeric or oligomeric brominated additives. A typical additive is an end-capped polycarbonate derived from tetrabromobisphenol-A [94334-64-2] another is a mixture of epoxy oligomers derived from the diglycidyl ether of tetrabromobisphenol-A [68928-70-1]. The brominated polystyrenes (Zoc. cit.) have only limited usefulness in PBT as they have a low melt compatibility (107). 

Additives that impart smoke-suppressant properties to a composition tend not to be flame retardant. Conventional flame retardant and smoke-suppressant formulations include phosphorus-containing compounds such as a phosphoric acid ester, ammonium poly(phosphate) and red phosphorus, or halogen containing compounds such as tetrabromobisphenol A, decabromodiphenyl oxide and chlorinated polymers, and metal compounds such as magnesium hydroxide, aluminum hydroxide and zinc borate (4). 

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