Synergism flame retardants

E. D. Wed, "Additivity, Synergism and Antagonism in Flame Retardancy - Recent Developments," paper presented at 3rdMnnualBCC Conference on... 

The antimony oxide/organohalogen synergism in flame retardant additives has been the subject of considerable research and discussion over the past twenty-five years (1-17). In addition to antimony oxide, a variety of bismuth compounds and molybdenum oxide have been the subject of similar studies (18-20). Despite this intensive investigation, relatively little has been conclusively established about the solid state chemical mechanisms of the metal component volatilization, except in those cases where the organohalogen component is capable of undergoing extensive intramolecular dehydrohalogenation. 

Tang, Y., Hu, Y., Wang, Y.S., Gui, Z., Chen Z., and Fan, W. 2003. Intumescent flame retardant-montmorillonite synergism in polypropylene-layered silicate nanocomposites. Polym. Inter. 52 1396-1400. 

The combination of melamine with hydrated mineral fillers can improve the fire retardancy behavior of PP, eliminating at the same time the afterglow phenomenon associated with these fillers used in isolation.70 Similarly in EVA copolymer, antimony trioxide used in combination with metal hydroxides has been reported to reduce incandescence.56 Chlorinated and brominated flame retardants are sometimes used in combination with metal hydroxides to provide a balance of enhanced fire-retardant efficiency, lower smoke evolution, and lower overall filler levels. For example, in polyolefin wire and cable formulations, magnesium hydroxide in combination with chlorinated additives was reported to show synergism and reduced smoke emission.71... 

R. Kozlowski, M. Wladyka-Przybylak, and H. Rydarowski, Flammability of polypropylene/clay nanocomposites-synergism with some flame retardants, Proceedings of the 17th BCC Conference on Flame Retardancy, M. Lewin (Ed.), Business Communications Co Editions, Norwalk, CT, 2006. 

Modesti, M. Lorenzetti, A. Besco, S. Hrelja, D. Semenzato, S. Bertani, R. Michelin, R.A.. Synergism between flame retardant and modified layered silicate on thermal stability and fire behaviour of polyurethane nanocomposite foams. Polym. Degrad. Stab. 2008, 93, 2166-2171. 

Lewin, M., Synergism and catalysis in flame retardancy of polymers, Polym. Adv. Technol., 2001, 12, 215-222. 

Markezich, R.L., Flame retardants Synergisms involving halogens, in Plastics Additives - An A-Z Reference, Pritchard, G. (Ed.), Chapman Hall, London, U.K., 1998, pp. 327-338. 

The addition of carbon black to ABS improves its hardness, modulus of rigidity, heat deflection temperature, and ultraviolet stability but reduces its ultimate strength, particularly its impact strength recent surface treatment techniques might alleviate this. Theoretically it could con-ribute to flame retardance, but this would require further studies of its synergism. 

Inorganic salts have long been known to provide flame retardancy on cellulosic material that will not be exposed to water, rain or perspiration. The French chemist Gay-Lussac proposed a borax and ammonium sulfate treatment as a flame retardant for cotton in 1820. Today, a mixture of boric acid and borax is still an effective flame retardant for cotton at 10 % solids add-on. Ammonium salts of strong acids, especially phosphoric acid (P/N synergism) are particularly useful as nondurable flame retardants for cellulose. Three commercially important products are diammonium phosphate, ammonium suifamate and ammonium bromide. These salts readily form the corresponding strong acids upon heating (Fig. 8.10). 

It is remarkable that the increase in activity in this area noted last year has been sustained, considering that phosphazenes are relatively expensive as fire retardants. Various aspects of this topic have been reviewed, " including the concept of N—P synergism in flame retardants. As usual, most interest centres on the propoxy- " and aryloxy-cyclophosphazenes " and the flame resistance of... 

Polymer Structure and Flammability Flame Retardation of Polymers Synergism in Flame Retardation Selection of Fire Retardants Flame Retardation of Polymeric Materials... 

Much literature discusses the flame retardation of various polymeric materials (10-15). The techniques of reducing the flammability of polymers, in principle, are based on one or more of the three fundamental approaches described earlier. This section deals with the concept of synergism and its application in reducing flammability, selection of fire-retardant additives, and flame retarding some specific polymer systems. 

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