Abstract
The 2,2',4,4',6,6'hexanitrostilbene, HNS, nucleant, used in the crystallisation of 2,4,6,trinitrotoluene, TNT, was precipitated from molten TNT and examined by differential scanning calorimetry, DSC, at several stages during purification by vacuum sublimation. During purification a broad endotherm, associated with nucleant decomposition, which could be resolved into two endotherms, depending on the sublimation temperature, was observed. Pure nucleant prepared at 70‡C showed a similar behaviour during thermal annealing for extended periods of time at >85‡C. Thus TNT, retained in the recrystallised HNS nucleant, may be migrating during the purification process or may occupy a range of lattice sites, which exhibit different activation energies for migration to the surface of the solid during thermal decomposition of the nucleant. Loss of TNT from the nucleant, during purification, could produce some free HNS. The activation energy for nucleant decomposition, which may be a two-stage processes with the initial mobility of the TNT being the limiting reaction, was estimated to be ∼210 kJ mol−. The lattice sites available for the TNT in the host HNS nucleant require elucidation and are the subject of further studies to be published at a later date.
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References
R. Meyer, Explosives, Third Edition, V.C.H. Publishers, Weinheim, F.R.G., 1988, p. 367.
W. S. Wilson, J. Crystal Growth, 71 (1985) 23.
M. J. Margolin and E. A. Skettini, Ammunition Loading Techniques, Explosives Development Section, Report 43 1985 Picatinny Arsenal.
A. R. V. Steele et al., British Patent 765210 (1975). See also F. Meissner, G. Waunnschaff and G. F. Othmer, Ind. Eng. Chem., 46 (1934) 718.
W. R. Eubank and R. W. Van Dolah, Report of the Naval Ordinance Test Station NOTS 316 (1950).
D. K. Philp and B. W. Thorpe, J. Crystal Growth, 35 (1976) 133.
M. A. Parry and B. W. Thorpe, Nucleation and Growth of TNT containings HNS, Report MRL-R-708, 1978, Materials Research Laboratory, Melbourne.
M. A. Parry and B. W. Thorpe, J. Crystal Growth, 47 (1979) 541.
M. A. Parry and B. W. Thorpe, The effective Nucleant During the Grain Modification of TNT Containing HNS, Report MRL-R-748, 1979.
M. A. Parry and B. W. Thorpe, Influence of HNS on the Microstructure and Properties of Cast TNT, Report MRL-R-812 1981.
P. Pelletier, F. Beaupre and J. G. Melancon, Effect of Additives on the Mechanical and Thermophysical Properties of TNT, Report CRDV R-4526/89, 1989.
L. Yng-Long et al., Propellants, Explosives and Pyrotechnics, 15 (1990) 22.
M. Cartwright and G. Collett, J. Energetic Materials, 11 (1993) 161.
M. Cartwright and C. J. Hill, J.Thermal Analysis, 44 (1995) 1021.
S. Back, J. L. Soderberg and E. L. Hakanson, English Patent 1, 249, 038, granted to Bofors Explosives A.G. 1971.
C. S. Choi and S. Portnoy, Phase Relations in HNS, TNT, RDX Systems, Int. Symp. on the Chemistry of HNS & TATB, P.E.R.M.E., Waltham Abbey, March 1979.
M. Cartwright and C. J. Hill, J. Energetic Materials, (1995), in press. 18 K. G. Shipp, J. Org. Chem., 31 (1966) 857.
H. C. Chang et al., Molecular Structure of TNT (2,4,6-trinitrotoluene) and HNS (2,2'4,4'6,6'-hexanitrostilbene) p 5–1 Proceedings of the 18th ICT Conference, Technology of Energetic Materials, Karlsruhe, Germany, 1987.
J. D. Wright, Molecular Crystals, Cambridge University Press 1987, p. 45.
Structural Imperfections in Organic Molecular Crystals, J. M. Thomas and J. O. Williams, Vol. 1, Surface and Defect Properties of Solids, Royal Society of Chemistry, 1972, p. 128.
Diffusion in Molecular Crystals, J. N. Sherwood, Vol. 2, Surface and Defect Properties of Solids, Royal Society of Chemistry, 1973, p. 256.
N. K. Adam, Physical Chemistry, Clarendon Press, Oxford 1960, p. 442.
E. S. Swinbourne, J. Chem. Soc., (1960) 2371.
J. D. Wright, see Ref [20] page 86.
W. R. Carper, L. P. Davis and M. W. Extine, J. Phys. Chem., 86 (1982) 459.
F. Gerrard and A. Hardy, Acta. Cryst., C44 (1988) 1283.
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Aziz, A., Cartwright, M. & Hill, C.J. Thermal stability of the crystallisation nucleant. Journal of Thermal Analysis 47, 1617–1628 (1996). https://doi.org/10.1007/BF01980908
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DOI: https://doi.org/10.1007/BF01980908