Tetrabromo-BPA

Fire resistant reinforced plastic was obtained by using tetrabromo-BPA based epoxide resin, BPA/DC monomer and prepolymer as well as an imidazole curing agent and Zn octoate [82],... 

Polycarbonate exhibits a relatively high oxygen index of 26. It may be further flame retarded by the addition of flame-retardant additives, including tetrabromo-BPA polymer, oligomer, or other bromi-nated additives, alkali metal salts,polytetra-fluoroethylene, phosphorus-containing additives, or silicones.Glass fillers or other inert fillers may also provide improved performance in Underwriters Laboratories (UL) flame testing. 

A number of commercially significant PC copolymers are produced. In addition to the previously discussed branched PCs (for extrusion and blow-molding applications) and copolymers of BPA with tetrabromo-BPA for enhanced flame retardancy, high-Tg polyester carbonate copolymers have been produced for a number of years (Bayer Apec , GE LEXAN PPC Tg approximately 190°C). Polyester carbonate copolymers can be produced via copolymerization of BPA with diacyl chlorides. Aromatic diadds produce high-Tg copolymers, while aliphatic diadds yield lower-Tg copolymers. A lower-Tg PC aliphatic polyester copolymer (GE LEXAN SP resin) exhibits enhanced flow and ductility in comparison to standard PC and is useful for thin-wall injection molding applications requiring ductility and ease of melt processability, such as personal communication devices. GE has recently introduced two new PC copolymers, a PC-siloxane copolymer (LEXAN EXL) and a copolymer of... 

BPA polycarbonates exhibit properties typical of aromatic polyesters with respect to flame resistance. Early on, flame resistance was enhanced in these materials by introducing tetrabromo BPA/BPA copolymers [48]. Although other, more sophisticated systems— particularly nonhalogenated ones— have since been discovered and commerciahzed, these brominated copolymers are still in use. 

Copolymers. The copolymer of tetrabromo-BPA and BPA was one of the first commercially successful copolymers (80). Low levels of the brominated comonomer lead to increased flame resistance (V-0 rating by UL-94), while having little effect on other properties. The homopolsrmer of tetrabromo-BPA can also be prepared (81,82), but only the oligomeric version has been commercialized. The polycarbonate of bis-4-hydroxyphenyl-l,l-dichloroethylene, prepared from chloral and phenol, followed by dehydrohalogenation, was investigated as another inherently flame-resistant polymer that retained good impact properties (83). 

Polyethylene and a peroxide initiator were added to the usual BPA/DC-BMI-epoxide resin composition. The use of unsaturated polyesters from tetrabromo-phthalic anhydride, maleic anhydride and ethylene glycol as well as of other fire retardants was also described [99]. 

Fire resistant polymers were obtained from brominated epoxynovolak resin, BPA/DC prepolymer, BMI, Zn acetate and benzoyl peroxide [103] or from an oligo-aspartimide (BMI-diamine reaction product), BPA/DC, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane (i.e. Tetrabromo-Bisphenol A) and 2-ethyl-4-methylimi-dazole [104]. A mixture of BPA/DC, BMI and epoxide resin with brominated polycarbonate, copoly[oxy-2,6-dimethylphenylene)-(oxy-2,3,6-trimethylphenylene)] and a catalyst was also suggested [105],... 

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