THERMAL-DEGRADATION OF PENTAERYTHRITOL DIPHOSPHATE, MODEL-COMPOUND FOR FIRE RETARDANT INTUMESCENT SYSTEMS .1. OVERALL THERMAL-DEGRADATION

The thermal degradation of pentaerythritol diphosphate (PEDP) has been extensively studied by means of various thermal analytical techniques. It is shown that on heating, PEDP degrades in several successive steps with the formation of a complex mixture of volatile products. The intumescent effect takes place between 280 and 350°C when PEDP melts and undergoes limited weight loss (c. 15%), with evolution of water as the major volatile product. Extensive degradation of the intumescent char occurs above 500°C with the formation of volatile acidic phosphorus-containing moieties. Further products evolved in the overall thermal degradation of PEDP to 900°C include, hydrocarbons, aldehydes, carbon monoxide and dioxide, methane, hydrogen and phosphine. © 1990.