Flame retardants poly vinyl alcohol and silicon compounds

In the modern polymer industry, the various existing types of polymer flame retardants based on halogens (Cl, Br), heavy and transition metals (Zn, V, Pb, Sb) or phosphorus-organic compounds reduce the risk from pol3nner combustion and p5n olysis, but may present ecological issues. The overall use of halogenated flame retardants is still showing an upward trend, but the above concerns have started a search for more environmentally friendly polymer additives. As a result it is quite possible that the future available flame retardants will be more limited than in the past. 

One ecologically-safe flame retardant system, containing a char former, is polyvinyl alcohol (PVA) combined with a sUicon-based inorganic system which can act in two ways as follows. 

By the formation of a barrier (char) which hinders the supply of oxygen and reduces the thermal conductivity of the material this is the role of the polyvinyl alcohol. 

By trapping the active radicals in the vapour phase (and eventually in the condensed phase) - this is the role of the silicon inorganic system. 

There is a strong correlation between char yield and fire resistance. Char is formed at the expense of combustible gases and the presence of a char 

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Flame retardants poly(vinyl alcohol) and silicon compounds Flame retardants synergisms involving halogens ... 

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