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Wang D.-X.,Beijing Institute of Technology | Chen S.-S.,Beijing Institute of Technology | Li Y.-Y.,Beijing Institute of Technology | Yang J.-Y.,Beijing Institute of Technology | And 2 more authors.
Journal of Energetic Materials

Additives are one of the most important factors that greatly affect the crystal characteristics of the high energy compound hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX, C3H6N6O6) and they have an influence on impact sensitivity. In this article, a growth morphology method was applied to obtain the crystal habit of RDX in a vacuum as well as the morphologically important faces, and molecular dynamics simulations were applied to calculate the interaction energy between these crystal faces and additive molecules for prediction of the additive-effect crystal habits of RDX. On this basis, crystal characteristics including crystal morphology, aspect ratio, and total surface charge were investigated. Then the particle size and surface electrostatic voltage of the samples from recrystallization were analyzed experimentally. The impact sensitivity test indicated that acrylamide, which could enhance the regularity and degree of sphericity of RDX crystals and effectively reduce the surface static electricity of RDX, was successful in reducing the impact sensitivity of RDX as an additive for crystallization. The above experimental results were in good agreement with the conclusions based on the theoretical calculations. © 2014 Copyright Taylor and Francis Group, LLC. Source

Li H.,Nanjing University of Science and Technology | Pan R.M.,Nanjing University of Science and Technology | Wang W.J.,CAS Shanghai Institute of Organic Chemistry | Zhang L.Y.,Gansu Yinguang Chemical Industry Group Co.
Applied Mechanics and Materials

3-Difluoroaminomethyl-3-methyl oxetane (DFAMO) was synthesized via the process of bromination, cyclization, ammonification, amino protection and fluorination with a total yield of 43% and GC purity of 96%. DFAMO was characterized by 1H, 19F, 13C nuclear magnetic resonance (NMR), fourier transform infra red (FTIR) and elemental analysis. The homopolymer of 3-difluoroaminomethyl-3-methyloxetane (PDFAMO), considered as energetic binder to be used in solid propellants and polymer bonded explosives, with a number-average molecular weight (Mn) about 3000 was synthesized via cationic ring-opening polymerization using boron trifluoride etherate (BTFE) as Lewis acid catalyst, 1,4-butanediol (BDO) as initiator and 1,2-dichloroethane (DCE) as aprotic solvent. The effects of BTFE/BDO feeding molar ratio and temperature of the polymerization reaction were discussed. The structure of PDFAMO was characterized by 1H and 19F NMR. © (2014) Trans Tech Publications, Switzerland. Source

Xiong S.-L.,Beijing Institute of Technology | Chen S.-S.,Beijing Institute of Technology | Li L.-J.,Beijing Institute of Technology | Jin S.-H.,Beijing Institute of Technology | Li J.-L.,Gansu Yinguang Chemical Industry Group Co.
Journal of Energetic Materials

A method for purity analysis of dihydroxylammonium 5,5ʹ-bistetrazole-1,1ʹ-diolate (TKX-50) using high-performance liquid chromatography (HPLC) was established by optimizing the chromatographic conditions: the detection wavelength was set at 200 nm, and the sample was separated by reverse-phase column (SinoChrom ODS-BP, 4.6 mm × 200 mm, 5 μm) using binary mobile phase acetonitrile and water (volume ratio of 50/50) with a flow rate of 1.0 mL/min at column temperature of 25°C. Normalization method, external standard method, and internal standard method were used to analyze the purity of TKX-50. The results indicate that the precision and accuracy of each method can satisfy the requirements of product analysis; however, the external standard method possesses higher accuracy and precision by comparison and is suggested to analyze the purity of TKX-50. Copyright © Taylor & Francis Group, LLC. Source

Li H.,Nanjing University of Science and Technology | Pan R.,Nanjing University of Science and Technology | Wang W.,CAS Shanghai Institute of Organic Chemistry | Zhang L.,Gansu Yinguang Chemical Industry Group Co.
Journal of Thermal Analysis and Calorimetry

Poly(3,3-bis(difluoroaminomethyl)oxetane/tetrahydrofuran), poly(3-difluoroaminomethyl-3-methyloxetane/tetrahydrofuran), and poly(3,3-bis(difluoroaminomethyl)oxetane/3-difluoroaminomethyl-3-methyloxetane/tetrahydrofuran) were synthesized via cationic bulk polymerization using boron trifluoride etherate/polyol mixture as catalyst system. Thermal decomposition behaviors of these polymers were investigated by thermogravimetric analysis/differential scanning calorimetry. Kinetics of thermolysis was studied by a model-free method. All of these polymers exhibited a two-stage mass-loss process. The elimination of HF with the activation energy at 95-110 kJ mol-1dominated the first stage, while the second stage contained the thermolysis of the remaining polymer chain with monofluoroimino and cyano groups. Fourier transform infra red spectra of the degradation residues showed that the difluoroamino groups decomposed in a two-step HF loss at different temperatures. The existence of monofluoroimino groups was responsible for the two-stage thermolysis process. © 2014 Akadémiai Kiadó, Budapest, Hungary. Source

Meng J.-J.,Beijing Institute of Technology | Jiang Z.-M.,Gansu Yinguang Chemical Industry Group Co. | Zhang X.-R.,Beijing Institute of Technology | Zhou L.,Beijing Institute of Technology
Binggong Xuebao/Acta Armamentarii

In order to obtain the system of functional agents for 2, 4-dinitroanisole(DNAN)-based melt-cast explosives and improve the performance of its charge, Tween 60 and cellulose acetate butyrate(CAB)are chosen as the preferred agents according to the calculated works of adhesion. The influences of functional agents on tensile strength, shear strength, impact sensitivity, friction sensitivity, shock sensitivity and charge density of DNAN 20/HMX 80 melt-cast explosive are analyzed by using Brazil test, static shear test, determination of friction sensitivity-explosion probability method, determination of impact sensitivity-explosion probability method, small scale gap test and hydrostatic weighing method. The results show that, when 1wt% Tween 60 and 1wt% CAB are added in DNAN 20/HMX 80 melt-cast explosive, its tensile strength is increased by 6.25%, 10.3% and 47.8% at -40 ℃, 20 ℃ and 60 ℃, respectively; its shear strength are increased by 23.5%, 27.8% and 45.1% at -40 ℃, 20 ℃ and 60 ℃, respectively; its friction sensitivity, impact sensitivity and shock sensitivity are decreased by 14.29%, 4.76% and 3.11%, respectively; and its relative density is increased by 0.2%. Therefore, Tween 60 and CAB can be used to improve the mechanical properties and safety performance of DNAN-based melt-cast explosives. © 2016, Editorial Board of Acta Armamentarii. All right reserved. Source

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