Thermal decomposition of RDX and mixtures

Abstract

Thermal decomposition of pure cyclotrimethylene trinitramine (RDX) shows an endothermic peak at 205°C attributed to melting, followed by exothermic decomposition leading to a strong peak at 240°C, and a very strong thermogravimetric peak at 260°C with a mass loss of 95%. However, the mixture of RDX, nitrocellulose and carbon (FX 300) shows a melting peak at 202°C with reduced intensity, and a decomposition peak at 255°C. A strong exothermic shoulder at 218°C, from the decomposition of nitrocellulose and other materials in the mixture is also seen. Addition of NH 4ClO 4 to RDX causes decomposition, after melting, to take place abruptly, resulting in a very sharp and strong peak at 210°C. However, in the case of FX300 no melting is observed; instead two strong exothermic peaks at 195 and 210°C occur, corresponding to the oxidation of nitrocellulose and RDX in the mixture. This indicates that the addition of NH 4ClO 4 increases the decomposition of RDX, this effect being more pronounced in FX300. The most appropriate concentration of NH 4ClO 4 is 10 wt%. Although NH 4NO 3 decomposes prior to the melting decomposition of RDX, it does not show a marked effect on the decomposition of RDX and FX300. Additions of KClO 4, NaClO 4 and KNO 3 have no effect.