Molecular Dynamics Simulation on CL-20/TNT Cocrystal Explosive†

doi:10.7503/cjcu20150605

Abstract

Abstract:

Molecular dynamics(MD) simulation was conducted for 2,4,6,8,10,12-hexanitrohexaazaiso-wurtzitane(ε-CL-20) and 2,4,6-trinitrotoluene(TNT) crystal, CL-20/TNT cocrystal with equal molar ratio and CL-20/TNT composite with equal molar ratio using COMPASS force field with isothermal-isobaric(NPT) ensembles at different temperatures. Their structures, interactions between different components and mechanical properties were investigated. The cohesive energy density(CED) of the cocrystal decreases with rising temperature, and is greater than that of the composite. The binding energy(E_bind) between two components of the cocrystal also decreases gradually with rising temperature, and is twice times as strong as that of the CL-20/TNT composite. In addition, pair correlation function analysis and enlarged local structure show that hydrogen bonds exist between the two components in the cocrystal and these bonds are mainly formed between H atoms in TNT and O atoms in CL-20, and H atoms in CL-20 and O atoms in TNT. The values of the tensile, bulk and shear modulus(E, K, G) for CL-20/TNT cocrystal fall in between those for ε-CL-20 and TNT crystals and decrease with increasing temperature, which agrees with general expectation. However, the Cauchy pressure(C₁₂-C₄₄), K/G and Poisson’s ratio(ν) for CL-20/TNT cocrystal are much larger than those for the two crystals, which predicts the cocrystal has much higher ductility and elastic elongation.

Key words: CL-20/TNT cocrystal explosive, Composite explosive, Mechanical property, Pair correlation function, Molecular dynamics

CLC Number:

O641
TJ55

TrendMD:

LIU Qiang, XIAO Jijun, ZHANG Jiang, ZHAO Feng, HE Zhenghua, XIAO Heming. Molecular Dynamics Simulation on CL-20/TNT Cocrystal Explosive^†[J]. Chem. J. Chinese Universities, 2016, 37(3): 559.

Figures/Tables 12

References 32

[1]	Lara O. F., Espinosa P. G., Supramolecular Chemistry, 2007, 19(8), 553—557
[2]	Stahly G. P., Crystal Growth and Design, 2009, 9(10), 4212—4229
[3]	Ji B. M., Deng D. S., Ma N., Miao S.B., Liu P., Li X. F., Chem. J. Chinese Universities, 2011, 32(9), 2114—2122
	(吉保明, 邓冬生, 马宁, 苗少斌, 刘鹏, 李贤飞. 高等学校化学学报, 2011, 32(9), 2114—2122)
[4]	Chen J. M., Wu C. B., Lu T. B., Chem. J. Chinese Universities, 2011, 32(9), 1996—2009
	(陈嘉媚, 吴传斌, 鲁统部. 高等学校化学学报, 2011, 32(9), 1996—2009)
[5]	Michael L., Propellant Made with Cocrystals of Cyclotetramethy Lenetetramine and AmmoniumPerchlorate,US 4086110, 1978-04-25
[6]	Levakova I. V., Korobko A. P., Krasheninnikov S. V., Zavodnik V. E., Kristallografiya,1996, 41(6), 963—965
[7]	Jin P. S., Xiao H. D., Qing P. L., Yong Z., Qiao L. B., Yong J. L., Chong H. P., Crystal Growth and Design,2011, 11, 1759—1765
[8]	Wei C. X., Duan X. H., Liu C. J., Liu Y G., Li J. S., Acta Chim. Sinica, 2009, 67(24), 2822—2826
	(卫春雪, 段晓惠, 刘成建, 刘永刚, 李金山. 化学学报, 2009, 67(24), 2822—2826)
[9]	Guo C. Y., Zhang H. B., Wang X. C., Sun J., Materials Review, 2012, 26(19), 49—53
	(郭长艳, 张浩斌, 王晓川, 孙杰. 材料导报, 2012, 26(19), 49—53)
[10]	Bolton O., Matzger A. J., Angew. Chem. Inter. Ed., 2011, 50(38), 8960—8963
[11]	Yang Z. W., Zhang Y. L., Li H. Z., Zhou X. Q., Nie F. D., Li J. S., Huang H., Chin. J. Energetic Materials, 2012, 20(6), 674—679
	(杨宗伟, 张艳丽, 李洪珍, 周小青, 聂福德, 李金山, 黄辉. 含能材料. 2012, 20(6), 674—679)
[12]	Yang Z. W, Huang H., Li H. Z., Zhou X. Q., Li J. S., Nie F. D., Chin. J. Energetic Materials, 2012, 20(2), 256—257
	(杨宗伟, 黄辉, 李洪珍, 周小清, 李金山, 聂福德. 含能材料. 2012, 20(2), 256—257)
[13]	Yang Z. W., Li H. Z., Huang H., Zhou X. Q., Li J. S., Nie F. D., Propellants, Explosives Pyrotechnics, 2013, 38(4), 495—501
[14]	Aldoshin S. M., Aliev Z. G., Goncharov T. K., Kazakov A. I., Milekhin Yu. M., Plishkin N. A., Shishov N. I. Russ. Chem. Bull., Int.Ed..2013, 62(6), 1354—1360
[15]	Liu H., Li Q. K., He Y. H., Acta Physica Sinica, 2013, 62(20), 208202
	(刘海, 李启楷, 何远航. 物理学报, 2013, 62(20), 208202)
[16]	Ou Y. X., Meng Z., Liu J. Q., Chemical Industry and Engineering Progress, 2007, 26(12), 1690—1694
	(欧育湘, 孟征, 刘进全. 化工进展. 2007, 26(12), 1690—1694)
[17]	Xiao H.M., Xu X, J., Qiu L., The Theoretical Design of High Energy Density Material, Science Press, Beijing, 2008, 19—32
	(肖鹤鸣, 许晓娟, 邱玲. 高能量密度材料的理论设计, 北京: 科学出版社, 2008, 19—32)
[18]	Xu X. J., Xiao H. M., Ju X. H., Gong X. D., Chinese Journal of Organic Chemistry,2005, 25(5), 536—539
	(许晓娟, 肖鹤鸣, 居学海, 贡雪东. 有机化学, 2005, 25(5), 536—539)
[19]	Agrawal J. P., Propellants,Explosives,Pyrotechnics.2005, 30(5), 316—328
[20]	Foltz M. F., Coon C. L., Garcia F., Nichols A. L., Propellants, Explosives Pyrotechnics, 1994, 19(1), 19—25
[21]	Sun H., J. Phys. Chem. B, 1998, 102(38), 7338—7364
[22]	Xu X. J., Xiao H. M., Xiao J. J., Zhu W., Huang H., Li J. S., J. Phys. Chem. B, 2006, 110(14), 7203—7207
[23]	Xu X. J., Xiao J. J., Huang H., Li J. S., Xiao H. M., Science in China B, Chemistry,2007, 50(6), 737—745
[24]	Zhou Y., Long X. P., Wei X. W., Journal of Molecular Modeling, 2011, 17(11), 3015—3019
[25]	Zhao X. Q., Shi N. C., Chinese Science Bulletin, 1995, 40(23), 2158—2160
	(赵信岐, 施倪承. 科学通报, 1995, 40(23), 2158—2160)
[26]	Vrcelj R. M., Sherwood J. N., Kennedy A. R., Gallagher H. G., Gelbrich T., Crystal Growth and Design,2003, 3(6), 1027—1032
[27]	Andersen H. C., J. Chem. Phys., 1980, 72(4), 2384—2393
[28]	Parrinello M., Rahman A., J. Appl. Phys., 1981, 52, 7182—7190
[29]	Xiao J.J.,Zhu W. H., Zhu W., Xiao H. M., Molecular Dynamics Study on High Energy Materials, Science Press, Beijing, 2013, 54—65
	(肖继军, 朱卫华, 朱伟, 肖鹤鸣. 高能材料分子动力学, 北京: 科学出版社, 2013, 54—65)
[30]	Pugh S. F., Philosophical Magazine, 1954, A45, 823—843
[31]	Pettifor D. G., Materials Science and Technology, 1992, 8(4), 345—349
[32]	Xiao J. J., Wang W. R., Chen J., Ji G. F., Zhu W., Xiao H. M., Computational and Theoretical Chemistry, 2012, 999, 21—27

T/K	a/nm	b/nm	c/nm	α/(°)	β/(°)	γ/(°)	ρ/(g·cm^-3)	V/nm³
95	0.935	1.958	2.470	90.00	90.00	90.00	1.94	4.521
	(0.004)	(0.009)	(0.005)	(0.18)	(0.14)	(0.13)	(0.01)	(0.011)
195	0.872	2.216	2.452	90.02	90.02	89.99	1.86	4.739
	(0.014)	(0.011)	(0.007)	(0.36)	(0.25)	(0.22)	(0.01)	(0.016)
245	0.878	2.210	2.462	90.01	90.01	90.00	1.85	4.775
	(0.003)	(0.005)	(0.009)	(0.42)	(0.27)	(0.25)	(0.01)	(0.179)
295	0.882	2.208	2.473	90.00	90.00	90.00	1.84	4.815
	(0.007)	(0.020)	(0.010)	(0.44)	(0.31)	(0.31)	(0.01)	(0.023)
345	0.886	2.211	2.483	89.99	89.99	90.00	1.82	4.860
	(0.008)	(0.021)	(0.011)	(0.49)	(0.34)	(0.33)	(0.01)	(0.024)
395	0.892	2.212	2.491	90.02	90.01	90.00	1.80	4.912
	(0.009)	(0.024)	(0.012)	(0.53)	(0.37)	(0.36)	(0.01)	(0.027)
Exp.^[5]	0.967	1.937	2.469	90.00	90.00	90.00	1.91	4.626

T/K	a/nm	b/nm	c/nm	α/(°)	β/(°)	γ/(°)	ρ/(g·cm^-3)	V/nm³
95	0.935	1.958	2.470	90.00	90.00	90.00	1.94	4.521
	(0.004)	(0.009)	(0.005)	(0.18)	(0.14)	(0.13)	(0.01)	(0.011)
195	0.872	2.216	2.452	90.02	90.02	89.99	1.86	4.739
	(0.014)	(0.011)	(0.007)	(0.36)	(0.25)	(0.22)	(0.01)	(0.016)
245	0.878	2.210	2.462	90.01	90.01	90.00	1.85	4.775
	(0.003)	(0.005)	(0.009)	(0.42)	(0.27)	(0.25)	(0.01)	(0.179)
295	0.882	2.208	2.473	90.00	90.00	90.00	1.84	4.815
	(0.007)	(0.020)	(0.010)	(0.44)	(0.31)	(0.31)	(0.01)	(0.023)
345	0.886	2.211	2.483	89.99	89.99	90.00	1.82	4.860
	(0.008)	(0.021)	(0.011)	(0.49)	(0.34)	(0.33)	(0.01)	(0.024)
395	0.892	2.212	2.491	90.02	90.01	90.00	1.80	4.912
	(0.009)	(0.024)	(0.012)	(0.53)	(0.37)	(0.36)	(0.01)	(0.027)
Exp.^[5]	0.967	1.937	2.469	90.00	90.00	90.00	1.91	4.626

Sample	T/K	vdW energy/(kJ·cm^-3)	Electrostatic energy/(kJ·cm^-3)	CED/(kJ·cm^-3)
CL-20/TNT cocrystal	195	0.37(0.01)	0.54(0.01)	0.91(0.01)
	245	0.36(0.00)	0.52(0.01)	0.88(0.01)
	295	0.36(0.00)	0.50(0.01)	0.86(0.01)
	345	0.35(0.00)	0.48(0.01)	0.83(0.01)
	395	0.34(0.00)	0.47(0.01)	0.81(0.01)
CL-20/TNT composite	295	0.31(0.01)	0.45(0.01)	0.76(0.01)

Sample	T/K	vdW energy/(kJ·cm^-3)	Electrostatic energy/(kJ·cm^-3)	CED/(kJ·cm^-3)
CL-20/TNT cocrystal	195	0.37(0.01)	0.54(0.01)	0.91(0.01)
	245	0.36(0.00)	0.52(0.01)	0.88(0.01)
	295	0.36(0.00)	0.50(0.01)	0.86(0.01)
	345	0.35(0.00)	0.48(0.01)	0.83(0.01)
	395	0.34(0.00)	0.47(0.01)	0.81(0.01)
CL-20/TNT composite	295	0.31(0.01)	0.45(0.01)	0.76(0.01)

Sample	T/K	E_bind/ (kJ·mol^-1)	Nonbond energy/ (kJ·mol^-1)	vdW energy/ (kJ·mol^-1)	Repulsive energy/ (kJ·mol^-1)	Dispersive energy/ (kJ·mol^-1)	Electrostatic energy/ (kJ·mol^-1)
CL-20/TNT cocrystal	195	178.90(0.37)	178.90(0.37)	65.73(0.21)	-181.76(0.77)	247.48(0.65)	113.17(0.39)
	245	176.77(0.26)	176.77(0.26)	65.94(0.24)	-178.47(0.60)	244.41(0.63)	110.83(0.31)
	295	174.19(0.30)	174.19(0.44)	65.50(0.39)	-176.72(1.32)	242.22(1.02)	108.69(0.64)
	345	169.43(0.42)	169.43(0.42)	64.78(0.26)	-170.80(0.99)	235.58(0.82)	104.65(0.34)
	395	166.18(0.65)	166.18(0.65)	63.82(0.39)	-166.96(1.05)	230.78(0.85)	102.36(0.39)
CL-20/TNT composite	295	75.27(0.42)	75.27(0.42)	29.66(0.19)	-74.03(0.62)	103.69(0.68)	45.61(0.29)