Polystyrene brominated

Poly(dibromostyrene). Poly(dibromostyrene) [62354-98-7] (PDBS) is prepared by the polymerization of dibromostyrene [31780-26-4] (50). Two versions are avaHable. One has a molecular weight of about 10,000, the other a molecular weight of about 80,000. Information comparing the performance of these materials to the performance of the brominated polystyrenes is not avaHable. 

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... 

For the large scale synthesis, the sodium salt of 2 formed in the NaCN-NaOH reaction could be purified by brominated polystyrene resin S P-207 chromatography to avoid acidic work-up which generates HCN. The SP-207 resin was first saturated with 1 M NaCl, and the crude reaction mixture was loaded onto the column. The column was then eluted with 1M NaCl to remove inorganic salts such as excess NaCN and NaOH and other polar impurities. Eluant switching to MeOH-H20 eluted the sodium salt of 2. Fractions containing >98.5 A% of... 

Three flame retardants were compared in this study, namely, a brominated polycarbonate oligomer (58% bromine), a brominated polystyrene (68% bromine), and a brominated triaryl phosphate ester (60% bromine plus 4% phosphorus). These are described in Table I. Figures 1 and 2 compare the thermal stability of the brominated phosphate with commercial bromine-containing flame retardants by thermogravimetric analysis (TGA) and by differential scanning calorimetry (DSC). The brominated phosphate melts at 110°C and shows a 1% weight loss at 300°C. Brominated polycarbonate and brominated polystyrene are polymeric and are not as volatile at elevated temperatures as the monomeric flame retardants. 

Various blend ratios of polycarbonate and PBT polyester were flame retarded with the three flame retardants. These data are shown graphically in Figure 3. Brominated phosphate is the most efficient and brominated polycarbonate the least efficient flame retardant. At a 50/50 ratio of polycarbonate/PBT, brominated phosphate is significantly more effective than brominated polystyrene. 

Brominated phosphate is a very efficient flame retardant as measured by oxygen index and UL-94 (Table IX and Figure 4). The melt index of the resin does not change with the addition of brominated polycarbonate, doubles with brominated polystyrene, and doubles again with brominated phosphate (Table IX). 

The flame retardant performance of various flame retardant additives in a commercial polycarbonate/ABS alloy were compared. No antimony oxide was required. The data shows brominated phosphate to be a highly efficient flame retardant in this alloy (Table XI). An alloy composition containing 14% brominated phosphate and no antimony oxide gives a V-0 rating (Table XII). The melt index of this alloy containing 12% brominated polystyrene was 7.6 g/10 min. (at 250°C) the equivalent resin containing brominated phosphate had a melt index of 13.3 g/10 min. 

Figure 4. Flame Retarding Polycarbonate/PET Polyester Alloy 1. brominated polycarbonate oligomer 2. brominated polystyrene 3. brominated aromatic phosphate ester...

Brominated diphenyl oxides, 77 461 Brominated epoxies, 70 383 Brominated epoxy ohgomers, 77 470 Brominated epoxy resin, 70 456 Brominated poly(isobutylene-co-p-methylstyrene), 4 438 blends with halobutyl, 4 453 copolymers, 4 446 vulcanization, 4 450 Brominated polystyrene(s), 77 470 474 20 65... 

Generally, flame retardants for engineering PET compositions are based on bromine-containing compounds (such as brominated polycarbonate, decabro-modiphenyl oxide, brominated acrylic, brominated polystyrene, etc.). Such compounds are available commercially (such as from the Ethyl Chemical Corporation, Great Lakes Chemical Corporation, Dead Sea Bromine Company, etc.) In addition, the flame-retardant package generally contains a synergist, typically sodium antimonate. PET may also be flame-retarded with diarylphosphonate, melamine cyanurate or red phosphorus. 

The two main brominated flame retardants used commercially in PET are PyroChek 68PB (see Figure 14.18) and Saytex HP-7010 (Albemarle). Both of these flame retardants are based on brominated polystyrene. While there are similarities between these flame retardants, they are not equivalents. There are quality and performance differences between these two products as they use different raw materials (i.e. polystyrenes) and the process for bromination is different. Saytex HP-7010 has better thermal stability and colour control than does PyroCheck 68 PB. However, if higher flow characteristics are a necessary property of the FR-PET, then Pyrocheck 68 PB would be the product of choice. Sodium antimonate is the appropriate synergist in PET since it is more stable at the higher processing temperatures required of PET and does not cause depolymerization of this polyesters. 

Brominated polystyrene PyroChek 68PB Albemarle Corporation... 

Brominated polystyrene is marketed as a fire-retardant additive. 

Nickel(II) catalysts with a direct nickel(II)-polystyrene bond have been prepared by oxidative addition of tetrakis(triphenylphosphine) nickel(O) to brominated polystyrene (58) ... 

Saigusa and Oda (196) have brominated polystyrene with N-bromo-succinimide in the presence of benzoyl peroxide 61% of the styrene units were brominated in the main chain. After dehydrohalogen-ation with sodium butoxide, the polymer contains 39% unchanged styrene units, 49% unsaturated groups, -CH=C-, and about 12%... 

Saigusa, T., and R. Oda Bromination of polystyrene with N-bromosuccini-mide, debromination of the brominated polystyrene, and grafting of vinyl acetate on the backbone of debrominated polystyrene. Bull. Ind. Chem. Research, Kyoto Univ. 33, 126 (1955) Chem. Abstr. 50, 1357 (1956). 

Decabromodiphenyl ether continues to be a popular fire-retardant additive for polyamide 6, its cost, high bromine content, and good thermal stability make it an attractive product. In Europe and the United States, most of its applications have been replaced by brominated polystyrene in order to address environmental issues. Brominated polystyrene is less expensive than the other polymeric fire retardants and has very good thermal stability. Moreover, it contributes to good electrical tracking index. On the other hand, it has lower efficacy as a fire retardant. 

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