The thermal decomposition of RDX at temperatures below the melting point. V. The evolution of occluded volatile matter prior to the decomposition, and the influence of past history of the sample on the rate of decomposition

Abstract

It is fist demonstrated that the occluded solvents and gases which are often present in RDX are expelled prior to zero reaction time of thermal decomposition. Thus they do not seriously interfere with the use of pressure increase as a measure of the extent of thermal decomposition. The rate of thermal decomposition of sublimed RDX at 195ºC is then compared with the rate after the following treatments, (i) preliminary grinding of the crystals, (ii) preparation of the crystals by different techniques, (iii) mixing RDX with various solid additives, (iv) interruption of the reaction by cooling, and (v) pre-irradiation with ultraviolet light. The results indicated that treatments (i), (ii), and (iv) had little effect on the rate, whereas (iii) and (v) could markedly influence the rate. Their effects are discussed in terms of the mechanism of decomposition. The results also indicated that there was a post-irradiation reaction of RDX at ambient temperature.