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1

Synthesis and Characterization of PolyNIMMO-HTPB-polyNIMMO Triblock Copolymer as a Potential Energetic Binder

Wang X., Shu Y., Lu X., Mo H., Xu M.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 3

456--467

EN

Triblock copolymer polyNIMMO-HTPB-polyNIMMO was synthesized by cationic ring opening polymerization of NIMMO (3-nitratomethyl-3-methyloxetane) in the presence of hydroxyl-terminated polybutadiene catalyzed by BF3·OEt2. The polymer was characterized by FT-IR, 1H NMR, 13C NMR spectroscopy, and GPC. DSC was used to investigate the thermal behaviour of the triblock copolymer and its exothermic decomposition peak was found to be at 215 °C. All of the results indicated that the triblock copolymer polyNIMMO-HTPB-polyNIMMO might serve as a potential energetic propellant binder.

2

Comparative Theoretical Investigation on Energetic Substituted Furazanyl Ethers

Liu N., Wang K., Shu Y., Zeman S., Wang B., Wang W.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 1

47--71

EN

Furazanyl ether has great potential to be an important candidate as a casting explosive and energetic plasticizer. The density functional theory (DFT) method was used to investigate the heats of formation (HOFs), molecular stability, detonation performance and melting point of a series of substituted furazanyl ethers at B3LYP/6-311G(d,p) level. The results show that the introduction of –N3 or –N(O)=N– groups significantly improves the HOFs values of the derivatives. The bond dissociation energies (BDEs) were analyzed, showing that the N–O bond in the furazan ring is the weakest for most compounds and the ring is vulnerable to cleavage in thermal decomposition. The calculation of density, detonation velocities and detonation pressures suggests that the substitution of –NF2, –CF(NO2)2, furoxan or –N(O)=N– group is an effective method for enhancing their detonation performance. The melting points were determined according to the variation of specific heat capacity, and good estimates were obtained in comparison with the available experimental data. Taking into account the detonation performance and melting point, four compounds are favoured for application in melt cast explosive or energetic plasticizers.

3

Computational Investigation on the Structure and Performance of Novel 4,7-dinitro-furazano-[3,4-d]-pyridazine Derivatives

Wang K., Shu Y., Liu N., Ding X., Wu Z., Lu Y.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 1

26--46

EN

Seven novel energetic 4,7-dinitro-furazano-[3,4-d]-pyridazine derivatives were designed, and their optimized structures and performances were studied by density functional theory (DFT) at B3LYP/6-311g(d,p) level. The detonation performances were estimated by the Kamlet-Jacobs equations. The results show that these compounds have high crystal densities (1.818-1.925 g·cm−3), detonation velocities (8.51-9.56 km·s−1) and detonation pressures (32.28-41.70 GPa). The bond dissociation energies (BDEs) of the weakest bond (N–O bond) vary from 70.889 kJ·mol−1 to 173.283 kJ·mol−1, and some of them exhibit higher BDEs than that of RDX (N–NO2 bond, 149.654 kJ·mol−1) and HMX (N–NO2 bond, 154.905 kJ·mol−1). M4 and M5 exhibit similar and higher detonation performance than RDX (8.81 km·s−1, 34.47 GPa). The detonation performance of M7 (9.56 km·s−1, 41.70 GPa) even surpasses that of HMX (9.10 km·s−1, 39.00 GPa). Otherwise, the specific impulse values of M1-M7 (266-279 s) outperform HMX (266 s) by 0-13 s, which indicates that M1-M7 may show better performance as monopropellants. It is concluded that density, heat of formation, stability, detonation performance and specific impulse of the designed compounds depend on the position and number of the N→O oxidation bonds.

4

Coating of LiBH4 and Its Effect on the Decomposition of RDX and AP

Ding X., Shu Y., Chen Z., Liu N., Gou B., Zhang J., Wu M., Xie G., Dang T.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 1

134--151

EN

The novel fuel additive LiBH4 was introduced as an energetic component for its outstanding hydrogen content, perfect burning performance and high reactivity. In order to limit the hygroscopicity and to improve the stability in the air, LiBH4 was coated on the surface with wax and polyester carbonate. The final product was characterized by scanning electron microscopy (SEM), X-ray photoelectron energy spectroscopy (XPS) and Raman spectroscopy, while the stability in air was investigated by regular checking of variations in weight. The results show that a uniform coating layer was formed on the surface of the LiBH4, and the coverage was estimated from the boron content as approximately 82%. A healing effect was confirmed on defective surfaces exposed to air; the coating layer improves the relative stability by 50.7%. Furthermore, LiBH4 as an additive to promote the thermal decomposition of 1,3,5-trinitro-1,3,5-trazinane (RDX) and ammonium perchlorate (AP) was explored by differential scanning calorimetry (DSC), in which the catalytic effects of pure LiBH4 and coated LiBH4 were compared, and indicated that the coating does not decrease the reactivity of LiBH4. It is suggested that surface coating with some inert materials is a simple and effective method for improving the storage and performance of LiBH4, while ensuring its reactivity.

5

The Reinforcement of the TNT System by a Newly-designed GAP-based Polyurethane-Urea: a Molecular Simulation Investigation

Qian W., Shu Y., Ma Q., Li H., Wang S., Chen X.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 2

411--426

EN

A glycidyl azide (GAP)-based polyurethane-urea (PUU) modifier used in the 1,3,5-trinitrotoluene (TNT)-based composite explosive was investigated by molecular simulation. Inter-molecular interactions were investigated using quantum chemistry calculation on the dimer of TNT and GAP-PUU, and attractive forces were found between the two molecules. The cohesive energy densities and the solubility parameters were obtained through molecular dynamics simulations combined with thermodynamic calculations on the TNT and GAP-PUU amorphous cell models, and the miscibility of the modifier in molten TNT was predicted to be good. The interaction energies and the mechanical properties were then obtained by molecular simulations and mechanical calculations on the solid-phase models of the GAP-PUU with TNT along three crystalline directions, and an improvement in the mechanical properties was predicted.

6

Operational model for vessel traffic using optimal control and calibration

Shu Y., Daamen W., Ligteringen H., Hoogendoorn S.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2015

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nr 42 (114)

70--77

EN

Due to the ever-increasing economic globalization, the scale of transportation through ports and waterways has increased sharply. As the capacity of maritime infrastructure in ports and inland waterways is limited, it is important to simulate vessel behavior to balance safety and capacity in restricted waterways. Currently many existing vessel simulation models focus mainly on vessel dynamics and maritime traffic in the open ocean. These models are, however, inapplicable to simulating vessel behavior in ports and inland waterways, because behavior in such areas can be influenced by many factors, such as waterway geometry, external conditions and human factors. To better simulate vessel behavior in ports and waterways, we developed a new maritime traffic model by adapting the theory of pedestrian models. This new model comprises two parts: the Route Choice Model and the Operational Model. The Route Choice Model has been demonstrated and calibrated in our recent study, in which the desired speed is generated. This paper presents the second part of the model, the Operational Model, which describes vessel behavior based on optimal control by using the output of the Route Choice Model. The calibration of the Operational Model is carried out as well. In the Operational Model, the main behavioral assumption is that all actions of the bridge team, such as accelerating and turning, are executed to force the vessel to sail with the desired speed and course. In the proposed theory, deviating from the desired speed and course, accelerating, decelerating and turning will provide disutility (cost) to the vessel. By predicting and minimizing this disutility, longitudinal acceleration and angular acceleration can be optimized. This way, the Operational Model can be used to predict the vessel speed and course. Automatic Identification System (AIS) data of unhindered vessel behavior in the Port of Rotterdam, the Netherlands, were used to calibrate the Operational Model. The calibration results produced plausible parameter values that minimized the objective function. The paths generated with these optimal parameters corresponded reasonably well to the actual paths.

7

Thermal Expansion of Explosive Molecular Crystals: Anisotropy and Molecular Stacking

Qian W., Zhang C., Xiong Y., Zong H., Zhang W., Shu Y.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 1

59--81

EN

Molecular dynamics simulations of three typical explosive crystals, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 1,1-diamino-2,2- dinitroethene (FOX-7) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), were carried out under NPT ensemble and selected force field. The equilibrium structures at elevated temperatures were obtained, which show that the stacking behaviour of the molecules does not change with temperature. The coefficient of thermal expansion (CTE) values were calculated by linear fitting methods, and the results show that the CTE values are close to the experimental results and are anisotropic. The total energies of the cells expanding along each single crystallographic axis were calculated by the periodic density functional theory method, indicating that the energy change rates are anisotropic, and correlation equations of the energy change vs. CTE values were established. The essence of the anisotropy of the explosive crystal’s thermal expansion was compared and elucidated.

8

UV-induced photodecomposition of 2, 2′, 4, 4′, 6, 6′-hexanitrostillbene (HNS)

Sun Y., Xu T., Shu Y., Zhong F.

Materials Science Poland

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2013

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Vol. 31, No. 3

306--311

EN

HNS (2, 2’, 4, 4’, 6, 6’-hexanitrostillbene) is a heat-resistant photosensitive explosive widely used in the booster charge. Investigation of the photodecomposition mechanism may provide important information for controlling and enhancing the detonation performance, also for the lifetime prediction. The UV-induced photodecomposition of HNS has been subjected to experimental studies. The UV-Vis spectra, X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance spectra (EPR) demonstrate the formation of NO2 free radicals and nitroso derivatives of HNS upon UV irradiation, which proves well known facts that C–NO2 breaking and removal of oxygen from the nitro group take part in the photodecomposition of HNS.

9

Review of the Photodecomposition of Some Important Energetic Materials

Sun Y., Shu Y., Xu T., Shui M., Zhao Z., Gu Y., Wang X.

Central European Journal of Energetic Materials

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2012

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Vol. 9, nr 4

411-423

EN

The photodecomposition mechanisms of energetic materials vary with molecular structure, photodissociation wavelength, the phase of the material, experimental pressure and temperature etc. In this paper, the significant progress on photodecomposition studies of some important energetic materials achieved in recent years is introduced in detail, including nitromethane, DMNA (dimethylnitramine), TATB (1,3,5-triamino-2,4,6-trinitrobenzene), RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), HMX (1,3,5,7-tetranitro-1,3,5,7- tetrazacycloctane) and CL-20 (2,4,6,8,10,12-hexanitrohexaazaisowurtzitane). The difficulties and prospects of photodecomposition research of energetic materials are also indicated.

10

Fluorescence Analysis as an Effective Method Used in Micro/Trace Explosive Detection

Liu Y., Shu Y., Liu Xue-yong., Xiong Y., Zhong Fa-chun., Sun Y.

Central European Journal of Energetic Materials

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2009

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Vol. 6, nr 3-4

303-311

EN

There are many kinds of explosives, and their detection methods vary. Nitroaromatic compound is one of the composition of the explosives commonly used. The fuorescence will be quenched when they touch the fuorescent conjugated polymers. General methods for explosives detection have been summarized in this paper, in addition the application of novel fuorescence analysis technique in explosives detection has been introduced. Fluorescent conjugated polymer as chemical sensing material for explosive detection has been reviewed in detail, also a novel fuorescent sensing flm self-assembled by fuorescent small molecule pyrene and homogeneous fuoroimmunoassay have been presented briefy. The development of fuorescence analysis used in the area of determining explosives has been prospected.

11

Study on the Tetrazine's C-N Heterocyclic Derivatives

Zhou Y., Shu Y., Long X. P., Wang X., Tian A.

Central European Journal of Energetic Materials

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2007

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Vol. 4, nr 1-2

67-81

EN

31 tetrazine's C-N heterocyclic derivativesbhave been investigated by density functional theory. Their optimized geometry structures, electronic structures, conjugation, molecular total energiesand heatsof formation(HOF) were calculated at the B3LYP/6-311G(d,p) level. The results show that most of the species keep a planar structure and exist considerable conjugation over the whole molecule, whichbenhances the stability of these derivatives.There aregood linear relationshipamongthe molecular total energy, HOF and N atoms in these species. Our study shows most of the species have high HOFs and relative stabilities. The HOFof these compounds are between 571.2KJ/mol and 827.2KJ/mol, so theymay bbe potential candidatesfor energetic materials.

12

Study on Primary Step of Initiation Mechanisms of Two Polynitro Arenes

Zeman S., Shu Y., Wang X.

Central European Journal of Energetic Materials

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2005

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Vol. 2, nr 4

47-54

EN

Each one of the 2,6-bis(2,4,6-trinitrophenylamino)-3,5-dinitropyridine (PYX) and 2,4,6-tris(3-methyl-2,4,6-trinitrophenylamino)-1 ,3,5-triazine (TMPM) molecules contains two potential centres of primary fission in its initiation. This fission should be accomplished by migration of the y-hydrogen atom to the oxygen atom of the ortho-nitro group ("trinitrotoluene mechanism"). The morę probable pathways of initiation of the named molecules are estimated from considerations involving the several relationships: (1) between impact sensitivity and the 13C NMR chemical shifts of some polynitro arenas; (2) between Mulliken charges on nitrogen atoms of the primarily reacting nitro group and onsets of thermal decompositions from differential thermal analyses of the said compounds; and, (3) with computations obtained using the DFT-B3LYP/3-21g methods in the GAUSSIAN 98/03 program.

13

A Computational Investigation of a Novel Explosive: DNTF

Zhang Ch., Shu Y., Wang X., Wu X., Zhao X.

Central European Journal of Energetic Materials

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2005

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Vol. 2, nr 2

45-53

EN

Computational investigation including molecular structure, crystal density, heat of formation, relative specific impulse, heat of detonation, detonation velocity and pressure on dinitrofurazanfuroxan (DNTF) was performed by quantum chemistry (density functional theory and Beck 3LYP hybrid density functional with 6-31G (d, p) basis set), molecular mechanics (Dreiding forcefield) and Monte Carlo methods. It can be deduced that DNTF is moderately sensitive and the N9-O10 bond is the weakest in the molecule and the trigger spot of decomposition by the molecular structure analyses. The mean values of the computational results of DNTF are: heats of formation of gas (HOF) and crystal state - 1113.8 and 992.5 kJ mol-1 respectively; heat of detonation (HOD) - 7119.0 kJ kg-1; relative specific impulse vs. HMX - 1.135; detonation velocity and pressure - 9.10 km s-1 and 38.3 GPa respectively. As a result, DNTF is more powerful than HMX and is a promising melt-cast explosive for its possessing high power, moderate sensitivity, low melting point and thermal stability. Additionally, the simulation data is consistent with experiment. So these methods can also be applied to other HEDM (high energetic density materials) designs.