Recrystallization of CL-20 and HNFX from solution for rigorous control of the polymorph type: Part II, Experimental studies

Degirmenbasi N., Peralta-Inga Z., Olgun U., Gocmez H., Kalyon D. M.

JOURNAL OF ENERGETIC MATERIALS, vol.24, no.2, pp.103-139, 2006 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 24 Issue: 2
  • Publication Date: 2006
  • Doi Number: 10.1080/07370650600672090
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.103-139
  • Keywords: CL-20, conventional crystallization, HNFX, micro-crystallization, polymorph analysis, powder diffraction, Rietveld analysis, CHEMISTRY


The recrystallization of CL-20 and HNFX to form different polymorphs was investigated by employing various experimental analyses, including micro-crystallization under myriad conditions, novel means of crystallization, analysis of polymorphs using powder diffraction, and Rietveld analysis. In the investigation all three groups of solvents: polar protic, non-polar aprotic, and dipolar aprotic solvents were employed. These results are reported in two parts with the experimental results reported here and the mathematical modeling results reported in Part I of this paper. The conventional crystallization techniques included combinations of solvent and anti-solvent system (including high molecular weight polymer melts), combination of solvents, the use of habit modifiers, and seeding. Other recrystallization techniques, which were also investigated included recrystallization under UV, under microwaves, upon freeze drying, upon annealing, in the presence of high molecular weight polymers, and under different hydrodynamic and hence different micro-mixing conditions.