Preparation of Sub‐Micron Sized CL‐20 and Its Mechanical and Thermal Properties

Abstract

AbstractHigh sensitivity limits the broad application of CL‐20 despite that it is considered as the most powerful explosive. Numerous efforts and technologies of fabricating CL‐20 with small particle size have been implemented for solving this problem. In this study, CL‐20 with sub‐micron particle size was prepared by superfine comminution technique. The results of impact and friction sensitivities tests showed that the mechanical sensitivities of CL‐20 were improved after ultra‐fine treatment. DSC results showed that the decomposition of CL‐20 advanced with the particle sizes decreased. The sub‐micron sized CL‐20 showed lower activation energy (Eα) compared to that of raw CL‐20, suggesting that particle size reduction is in favour of decreasing the threshold of decomposition. The reaction models of CL‐20 with different particle sizes could all be categorized as n‐th order reactions with autocatalysis. The function of reaction mechanism could be expressed as f(α)=(1‐α)n(1+kcat•α). On aspect of heat sensitivity, the results of deflagration point tests showed that although particle size had little influence on the deflagration point with 5 s delay time (Tb) of CL‐20, apparent activation energy of explosion (Eb) decreased apparently with the particle sizes decreased, which could impact the thermal sensitivity significantly.