Focus Fire Extinguishers

Reviews of cyclophosphazene chemistry have focused on several important subtopics rather than comprehensive surveys or overviews. A comprehensive review of polymers derived from addition polymers of olefins attached to cyclophosphazenes has appeared. Synthesis, copolymerization and quantitative studies of monomer reactivity are discussed in detail. A comprehensive two part review of hybrid phosphazene-siloxane systems includes cyclophosphazenes with siloxane substituents and polymers derived from hydrosilation of alkenylphosophazenes. A survey of new generation candidates for currrently banned Halon fire extinguishing agents concludes that phosphazenes are superior to halons in lab scale extinguishment tests. ... 

This chapter will focus on radicals. We will learn about their structure and reactivity, and we will explore some of the important roles that radicals play in the food and chemical industries and in our overall health. We will also return to the topic of fire to explain how specially designed chemicals are able to destroy the radical intermediates in a fire, thereby stopping the combustion process and extinguishing the fire. 

Thermosetting nanocomposites exhibit a reduced rate of heat release compared to neat polymer. However, the approach to nanocomposites itself is not sufficient to comply with the actual fire test standards. For this reason, traditional flame retardants are currently used in combination with nanofillers, and researchers are focusing on the individuation of synergistic systems. As an alternative to the most common cationic clays, anionic clays show improved performance in terms of flame retardancy. Epoxy nanocomposites based on anionic clay exhibit unique self-extinguishing behavior in a UL-94 horizontal burning test never observed before in a pure nanocomposite. The formation of a continnous intu-mescent ceramic layer on the surface of a polymer during combustion reduces the heat release rate to a higher extent than do montmorillonite nanocomposites. 

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