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A New Method for Predicting the Friction Sensitivity of Nitramines

Keshavarz M. H., Hayati M., Ghariban-Lavasani S., Zohari N.

Central European Journal of Energetic Materials

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2015

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Vol. 12, no. 2

215--227

EN

This study presents a new simple correlation between friction sensitivity of nitramines and their molecular structures. This novel correlation can help chemists and chemical engineers to predict the friction sensitivity of new nitramines without using any experimental data, which is important for safety in industrial processes. The new correlation can also help to elucidate the mechanism of initiation of energetic materials by frictional stimuli. This new method assumes that friction sensitivity of a nitramine of general formula CaHbNcOd can be expressed as a function of the optimized elemental composition and the contributions of specific molecular structural parameters. The new correlation has root mean square and average deviations of 7.64 and 6.44 J, respectively, for 20 nitramines with different molecular structures. The proposed new method was also tested for 11 nitramines containing complex molecular structures.

2

Energetic Nitrogen-Rich Polymers Based on Cellulose

Betzler F. M., Klapötke T. M., Sproll S.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 3

157-171

EN

New nitrogen-rich polymers, based on cellulose, were synthesized using common procedures. The point of interest was the introduction of tetrazole and nitramine moieties. The polymers were characterized by elemental analysis and vibrational spectroscopy (IR). The energetic properties were investigated using differential scanning calorimetry and bomb calorimetric measurements. Several detonation parameters, such as the detonation pressure, velocity, energy and temperature were computed using the EXPLO5 code. In addition, the sensitivities towards impact and friction were tested using the BAM drophammer as well as a friction tester.

3

The Elimination of NO2 from Mixtures of the Nitramines HMX, RDX and CL20 with the Energetic Binder Glycidyl Azide Polymer (GAP) - A Computational Study I

Bohn M. A., Hammerl A., Harris K., Klapötke T. M.

Central European Journal of Energetic Materials

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2005

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Vol. 2, nr 2

29-44

EN

The energetic plasticizer glycidyl azide polymer (GAP) is used for new types of rocket propellants which are formulated with the objective of achieving higher burning rates. The reaction profiles for several possible initial steps in the decomposition of mixtures of the nitramines octahydro-1,3,5,7-tetranitro-1,3,5,7- tetrazacyclooctane (HMX), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and hexanitrohexaazaisowurtzitane (CL20) with a monomer of GAP-diol have been examined computationally. Comparison of the activation energies for the decomposition of the mixtures with those for the decomposition of the isolated nitramines shows that the presence of GAP-diol decreases the activation energy for the elimination of NO2 by at least to 8 kJ mol-1 for CL20, wheras the NO2 elimination from HMX is only favored by 1 kJ mol-1 and NO2 elimination from RDX is inhibited in the presence of GAP-diol by 2 kJ mol-1.

4

Further Decomposition Pathways of Mixtures of the Nitramines HMX, RDX and CL20 with the Energetic Binder Glycidyl Azide Polymer (GAP) - A Computational Study II

Bohn M. A., Hammerl A., Harris K., Klapötke T. M.

Central European Journal of Energetic Materials

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2005

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Vol. 2, nr 3

3-19

EN

The energetic plasticizer glycidyl azide polymer (GAP) is used for new types of rocket propellants which are formulated with the objective of achieving higher burning rates. While the homolytic fission of an N-NO2 bond, which we discussed previously, is energetically favored as the initial decomposition step, experiments show that the decomposition of mixtures of the nitramines octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and hexanitrohexaazaisowurtzitane (CL20) with a monomer of GAP-diol is more complex. Therefore we investigated further possible decomposition pathways. Comparison of the calculated activation energies for the decomposition of the mixtures with those for the decomposition of the isolated nitramines shows that the presence of GAP-dioldecreases the activation energies of certain decomposition steps by up to 20 kJ mol-1. GAP-diol facilitates the decomposition of CL20 and RDX to a larger extent than the decomposition of HMX. However, the investigated decomposition pathways of GAP-diolwere inhibited by the presence of the nitramines.