Under the influence of heat intumescent paints with stoichiometric compositions decomposed to defined Compounds: Ammonium polyphosphate degraded to polyphosphoric acid and ammonia. Polyphosphoric acid reacted with pentaerythritols and glycerol to cyclic phosphoric acid esters, which were identified as the blowing agents. Melamine and polyphosphoric acid combined to melamine polyphosphate and dipolyphosphate. In further degradation of potyphosphoric acid, it dehydrated to phosphorus pentoxide, which reacted with titanium dioxide further to titanium pyrophosphate. Intumescent paints with higher efficiency could be developed by the addition of glycerol, which reacted to phosphoric esters with lower temperatures of decomposition. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 1745-1756, 2009