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Guo X.-Y.,Beijing Institute of Technology | Zhang P.,Beijing Institute of Technology | Xu J.-J.,China Academy of Engineering Physics | Wang Z.-H.,Liaoning Qingyang Special Chemical Co. | Jiao Q.-J.,Beijing Institute of Technology
Central European Journal of Energetic Materials | Year: 2015

In order to explore the polymorphic transition law for ε-CL-20 in composite systems, the polymorphic transition process of pure ε-CL-20 crystals stimulated by heat was investigated by the X-ray Diffraction (XRD) method, and the kinetic parameters of the polymorphic transition process were calculated (including the apparent activation energy Ea and the pre-exponential factor lnA). Meanwhile the effects of different additives on the polymorphic transition process and kinetics of ε-CL-20 were explored in detail. The experimental results showed that the ε-form tends to transform into the γ- form on heating and that the Ea and lnA for the transition process were 209.97 kJ/mol and 57.47, respectively. The first group of additives clearly promoted the polymorphic transition of ε-CL-20 and lowered the initial transition temperature and the activation energy. The second and third groups of additives inhibited the polymorphic transition of ε-CL-20 and raised the initial transition temperature and the activation energy.


Zhang P.,Beijing Institute of Technology | Guo X.-Y.,Beijing Institute of Technology | Zhang J.-Y.,Beijing Institute of Technology | Wang Z.-H.,Liaoning Qingyang Special Chemical Co. | Li S.-W.,Liaoning Qingyang Special Chemical Co.
Hanneng Cailiao/Chinese Journal of Energetic Materials | Year: 2013

The spherical superfine CL-20 were prepared using a physical grinding machine with three kinds of grinding balls, and the mechanism of the machine was introduced. The effects of the density of grinding balls and grinding time on the physical structures such as average particle size, particle size distribution and roundness and mechanical sensitivity of superfine CL-20 were studied. Results show the superfine CL-20 particles obtained with low-density grinding balls are spherical, and its mechanical sensitivity is significantly reduced, and its thermal stability is better than raw CL-20, and the polymorph remains ε-type. The high-density grinding balls can refine the materials well, while the smoothing effect of low-density grinding balls is better, and the particle-size distribution of superfine CL-20 is uniform and concentrated with roundness up to 0.9.


Guo X.-Y.,Beijing Institute of Technology | Jiang X.-B.,Beijing Institute of Technology | Yu L.,Beijing Institute of Technology | Zhang P.,Beijing Institute of Technology | And 3 more authors.
Huozhayao Xuebao/Chinese Journal of Explosives and Propellants | Year: 2013

Three kinds of ε-HNIW samples with different particle size and morphology were prepared by drowning-out recrystallization, and characterized by laser granularity measurement, polarization microscope and scanning electron microscope (SEM). The impact and friction sensitivity were tested and the thermal stability of HNIW samples were recorded by differential scanning calorimetry (DSC). Results indicated that the impact sensitivity of HNIW reduced rapidly with decreasing of particle size, thermal stability of HNIW reduced slowly. However, the friction sensitivity increased gradually along with the decreasing of particle size. HNIW with broad size distribution had higher mechanical sensitivity and thermal stability than samples with narrow size distribution. The HNIW with regular morphology had lower mechanical sensitivity and better thermal stability than samples with irregular crystals. The order of influencing factors on impact, friction and thermal decomposition of HNIW are particle size, size distribution and morphology.


Shen F.-F.,Beijing Institute of Technology | Zhang J.,Beijing Institute of Technology | Dong K.,Beijing Institute of Technology | Sun C.-H.,Beijing Institute of Technology | And 3 more authors.
Huozhayao Xuebao/Chinese Journal of Explosives and Propellants | Year: 2013

To establish feasible method to determine the acid value of hexanitrohexaazaisowurtane (CL-20), through comparing potentiometric titration method with indicator titration method and screening out the best solvent and indicator, the best system to determine the acid value was obtained. The results show that the optimum potentiometric titration system is sodium hydroxide/water solution as titrant and mixed solution of 250 mL slightly acidic acetone and 50 mL water as solvent. The optimum indicator titration system is the above titrant and solvent, and the neutral red-methylene blue as the indicator. The standard deviation of above two methods is less than 0.00030311% and the minimum is 0.00001%. The relative standard deviation of above two methods is less than 0.99949%, and the minimum is 0.19458%. The substitution of potassium hydroxide/ethanol for the sodium hydroxide/water in the above titrant can also meet the operating requirement.


Ouyang G.,Nanjing University of Science and Technology | Guo X.-D.,Nanjing University of Science and Technology | Xi H.-J.,Liaoning Qingyang Special Chemical Co. | Liu J.,Nanjing University of Science and Technology | And 2 more authors.
Binggong Xuebao/Acta Armamentarii | Year: 2015

Submicron hexanitrohexaazaisowurtzitane (CL-20) is prepared using HLG-50 pulverized machine. The laser particle size analyzer and SEM are used to characterize the particle size, size distribution and morphology of sample. The polymorph and purity of CL-20 particles are characterized by Fourier transform infrared spectrometer, laser Raman spectrometer, XRD and HPLC, respectively. The TG/DSC simultaneous thermal analyzer is used to study the thermal decomposition of CL-20.The shock sensitivity of samples are studied. The results show that CL-20 particles are pseudo-spherical with an average particle size (d50) of 210 nm. The polymorph of submicron CL-20 is consistent with that of the raw ε-CL-20.Compared with the raw CL-20, the thermal decomposition peak temperature of the submicron CL-20 is decreased slightly, and the shock sensitivity of the submicron CL-20 is considerably reduced by 53.1%. That implies the obvious reduction in the shock sensitivity of CL-20. ©, 2015, China Ordnance Society. All right reserved.

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