Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Central European Journal of Energetic Materials

2 2019

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Prediction of the Crystalline Densities of Aliphatic Nitrates by Quantum Chemistry Methods

Wang Guixiang, Xu Yimin, Xue Chuang, Ding Zhiyuan, Liu Yan, Liu Hui, Gong Xuedong

Central European Journal of Energetic Materials

2019

Vol. 16, no. 3

412--432

Crystal density is a basic and important parameter for predicting the detonation performance of explosives, and nitrate esters are a type of compound widely used in the military context. In this study, thirty-one aliphatic nitrates were investigated using the density functional theory method (B3LYP) in combination with six basis sets (3-21G, 6-31G, 6-31G*, 6-31G**, 6-311G* and 6-31+G**) and the semiempirical molecular orbital method (PM3). Based on the geometric optimizations at various theoretical levels, the molecular volumes and densities were calculated. Compared with the available experimental data, the densities calculated by various methods are all overestimated, and the errors of the PM3 and B3LYP/3-21G methods are larger than those of other methods. Considering the results and the computer resources required by the calculations, the B3LYP/6-31G* method is recommended for predicting the crystalline densities of organic nitrates using a fitting equation. The results obtained with this method are slightly better than those reported by Keshavarz and Rice. In addition, the effects of various groups (such as –ONO2, –OH, –Cl, –O–, and –CH2–) on the densities are also discussed, which is helpful for the design of new molecules in terms of practical requirements.

A Theoretical Study of Polyethylene Glycol Polynitrates as Potential Highly Energetic Plasticizers for Propellants

Wang Guixiang, Xu Yimin, Zhang Wenjing, Gong Xuedong

Central European Journal of Energetic Materials

2019

Vol. 16, no. 2

194--215

Polyethylene glycol polynitrates may be used as plasticizers in propellants. In this study, ten derivatives of ethylene glycol dinitrate were investigated using the density functional theory method. The fitted densities (ρ’exp.) were obtained and were very close to the experimental values. The detonation properties were predicted using the modified Kamlet-Jacobs equations and the specific impulse (Is) was evaluated according to the largest exothermic principle. A new indicator, K = Is · ρ’exp., is proposed to evaluate the energetic characteristics of the plasticizers. Thermal stability is discussed by calculating the bond dissociation energies or energy barriers. The O−NO2 bond is the trigger bond for all of the compounds studied. Considering the energetic properties and stability, diethylene glycol tetranitrate, triethylene glycol hexanitrate, tetraethylene glycol octanitrate, pentaethylene glycol decanitrate and hexaethylene glycol dodecanitrate are potential energetic plasticizers for solid propellants. The influences of the −O−CH2−CH2− and −O−CH(ONO2)−CH(ONO2)− groups are also discussed, which will be helpful for the design of new highly energetic plasticizers by modifying the structures as required.