Effect of Ammonium Halides On the Combustion of Polystyrene

Abstract

Effect of NH4Cl and NH4Br has been studied on combustion and decomposi tion of polystyrene (PS). NH4Br, at low concentrations showed unfavourable ef fects on burning rate, which is surprising for an accepted fire retardent. NH4Br accelerated degradation and combustion of PS. Thermogravimetric (TG) studies of PS + NH4Br samples in N 2 showed that these samples degraded at lower temperatures and with faster rates compared to neat PS. In O2 atmosphere the sensitization of the degradation started after about 30-40% weight loss. The dif ferential thermal analysis (DTA) of these samples gave some additional informa tion : both NH4Cl & NH4Br shifted the degradation temperature to a lower value than PS and exhibited exothermic reactions in the temperature range 400- 450 °C (more exothermicity in NH4Br samples).