Molecular modeling – Toward a realistic approach to model energetic materials

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Authors
  1. Brochu, D.
  2. Jaidann, M.
  3. Abou-Rachid, H.
  4. Neidert, J.
  5. Brisson, J.
Corporate Authors
Defence Research and Development Canada, Valcartier Research Centre, Quebec QC (CAN);Laval Univ, Quebec Que (CAN) Faculte des Sciences de l'Administration
Abstract
Models of plastic-bonded explosives were created with the aim of studying the mechanical properties and sensitivity because the latter is one of the most important problems in relation to energetic materials. Previous models proposed in the literature used short plastic chains, which are appropriate for interaction modeling. In the present work, a model with a single, long chain was built, which is more appropriate for modeling mechanical properties. The representative hydroxyl-terminated polybutadiene (HTPB)/dioctyladipate (DOA)/cyclotrimethylenetrinitramine (RDX) system was used (81.4 w/w% of RDX and 18.6 w/w% of the amorphous HTPB/DOA phase, with a 60/40 ratio between the polymer and plasticizer). The HTPB chain was composed of 48 trans groups, 16 cis groups, and 16 vinyl groups. Due to the length of the chain, superposing the crystalline RDX cell [cleaved at the crystalline (2 0 0), (0 2 0), and (2 1 0) planes] to the amorphous HTPB/DOA cell introduced considerable void, and therefore resulted in low density—much more so than when using models with shorter chains. A compression/minimization iterative procedure was used to converge to the optimal density. Pair distributions were calculated to verify that the procedure did not lead to abnormal changes in the RDX crystal model. Comparable energies were obtained for models built with each cleavage plane, contrary to previous work with small molecules. Long chains have lower entropy and are less able to change conformations
Keywords
energetic materials;simulation and modeling;sensivity;HTPB;RDX;plastic-bonded explosives
Report Number
DRDC-RDDC-2017-P115 — External Literature
Date of publication
01 Dec 2017
Number of Pages
19
Reprinted from
International Journal of Energetic Materials and Chemical Propulsion, no 12(4), p 319-333, 2013
DSTKIM No
CA045591
CANDIS No
806016
Format(s):
Electronic Document(PDF)

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