Synergism and catalysis in flame retardancy of polymers

Abstract Synergististic and catalytic effects in flame retardancy technology are reviewed. An attempt is reported to define and determine the synergistic effectivity (SE) and the catalytic effectivity (CAT‐EFF) of a number of systems operating according to the accepted mechanism. Synergistic effects in the halogen based gas phase systems involving Br / Sb 2 O 3 , Cl / Sb 2 O 3 , Br / NH 3 , Br/Cl, Br/P, and of the condensed phase based intumescent systems— ammonium polyphosphate/pentaerythritol/N derivatives are discussed and compared. Recently discovered catalysis of intumescent systems by divalent and transition metal compounds involving a maximum effect catalyst concentration is discussed in the light of thermoanalytical data. Recent work on catalysis of endothermic flame retardancy systems based on aluminum trihydrate and magnesium hydroxide are also reviewed. Copyright­© 2001 John Wiley & Sons, Ltd.