NEW ASPECTS OF ECOLOGICALLY-FRIENDLY POLYMER FLAME-RETARDANT SYSTEMS

In the modern polymer industry, different types of polymer flame retar dants based on halogens (Cl, Br), heavy and transition metals (Zn, V, Pb, Sb) or phosphorus-organic compounds may reduce risk during polymer combustion and pyrolysis, yet may also present ecological issues. The overall use of halogenated flame retardants is still showing an upwar d trend, but the preceding concerns have started a definite search for environmentally friendly polymer additives. As a result of these tren ds, it is quite possible that the available selections of polymer flam e retardants will be more limited than in the past. In our research we have focused on ecologically safe flame retardant systems (high tempe rature polymer-organic char former, polyvinyl alcohol and Si-inorganic system) which can act: 1. by the formation of a barrier (char) which hinders the supply of oxygen and reduces the thermal conductivity of t he material to limit heat transfer (char) - polyvinyl alcohol char for mer; and 2. by trapping the active radicals in the vapor phase (and ev entually in the condensed phase) - Si-inorganic system. (C) 1996 Publi shed by Elsevier Science Limited