Thermal reactivity studies were carried out in the temperature range 100–160‡ on two double-base propellant compositions which differ significantly in chemical composition, calorimetric value and ballistic characteristics. The course of decomposition was followed by two methods: (i) determining the rate of NO evolved with the Bergman and Junk method; (ii) estimating the volume of gases evolved in a vacuum stability test method. The activation energy values computed using the Arrhenius equation and the Jacobs-Kureishy method were comparable and in the range 134–170 kJ mol−1. In the temperature range 100–140‡, nitroglycerine volatilization was significant during the early stages of heating. Above 180‡, the rate of decomposition was very fast, leading to ignition of the propellant, followed by slow oxidation of the carbonaceous residues. The thermoanalytical data indicated a twostep decomposition process for propellant I, and a single-step process for propellant II.
Authors:J. Yi, F. Zhao, S. Xu, L. Zhang, X. Ren, H. Gao, and R. Hu
The decomposition reaction kinetics of the double-base (DB) propellant (No. TG0701) composed of the mixed ester of triethyleneglycol
dinitrate (TEGDN) and nitroglycerin (NG) and nitrocellulose (NC) with cerium(III) citrate (CIT-Ce) as a combustion catalyst
was investigated by high-pressure differential scanning calorimetry (PDSC) under flowing nitrogen gas conditions.
The results show that pressure (2 MPa) can decrease the peak temperature and increase the decomposition heat, and also can
change the mechanism function of the exothermal decomposition reaction of the DB gun propellant under 0.1 MPa; CIT-Ce can
decrease the apparent activation energy of the DB gun propellant by about 35 kJ mol−1 under low pressure, but it can not display the effect under high pressure; CIT-Ce can not change the decomposition reaction
mechanism function under a pressure.
Authors:Nirmala Sikder, N. Bulakh, A. Sikder, and B. Gandhe
Qualitative and quantitative analysis of the organic components of composite modified double-base (CMDB) propellants have been performed by HPTLC. The method enabled analysis of a five-component mixture in less than 10 min. The relative distribution of the components of the mixture was determined by means of a UV absorbance detector capable of monitoring at several different wavelengths and of providing UV spectra which could be used to assess peak purity. Detection limits were at nanogram levels.
The thermal decompositions of a double-base propellant (DB), five triple-base propellants (TB) and nitroguanidine (NGV) were
examined. The kinetic parameters were evaluated using the ASTM, Kissinger, Rogers-Morris, Freeman-Carroll and Borchardt-Daniels
methods. The values of the orders of some of the chemical reactions (n), like some values of activation energies (Ea), do not have any physical meaning, but they represent the manner of propellant decomposition and prove that the mechanism
of the reaction changes during the decomposition process. As a result of this fact, differences appear in the evaluated kinetic
parameters between various methods.
Authors:Xiao-Ling Xing, Feng-Qi Zhao, Shun-Nian Ma, Si-Yu Xu, Li-Bai Xiao, Hong-Xu Gao, and Rong-Zu Hu
soon. The main application of CMDB propellant containing CL-20 is to improve the energy and burning rate of the double-basepropellant for achieving the minimum signature properties with desirable energies. The effect of CL-20 on the thermal
Authors:Yanchun Li, Kou Chenxia, Chuan Huang, and Yi Cheng
replacements for NG in propellants.
TEGDN/NC propellant is double-basepropellant composed of TEGDN and NC. The addition of catalyst can effectively improve the combustion performance of propellant. Many researches have been done in this field. With the
The mechanical properties of solid rocket propellants are very important for good functioning of rocket motors. During use
and storage the mechanical properties of rocket propellants are changing, due to chemical and mechanical influences such as
thermal reactions, oxidation reactions or vibrations. These influences can result in malfunctioning, leading to an unwanted
explosion of the rocket motor. Most of modern rocket propellants consist of a polymer matrix (i.e. HTPB) filled with a crystalline
material (i.e. AP, AN). However, the more conventional double base propellants consist of a solid gel matrix with additives,
such as stabilizers. Both materials show a mechanical behaviour, quite similar to that of general polymers. To describe the
material behaviour of both propellants a linear visco-elastic theory is often used to describe the mechanical behaviour for
small deformations. Because the time-temperature dependency is also valid for these materials a mastercurve can be constituted.
With this mastercurve the response properties (stiffness) under extreme conditions can be determined. At TNO-PML a mastercurve
of a double base propellant was constituted using dynamical mechanical analysis (DMA) and compared with a mastercurve reduced
from conventional (static) stress relaxation tests. The mechanical properties of this double base propellant determined by
DMA were compared with conventional (quasi-static) tensile test results.
Authors:Z. Dang, F. Zhao, S. Li, C. Yin, and R. Hu
The thermal decomposition characteristics of1,7-diazido-2,4,6-trinitrazaheptane (DATH) and multi-component systems containing
DATH were studied by using DSC, TG and DTG techniques. Three –NO2 groups in the DATH molecule break away first from the main chain when DATH is heated up to 200C. Following this process,
the azido groups and the residual molecule decompose rapidly to release a great deal of heat within a short time. In the multi-component
systems, DATH undergoes a strong interaction with the binder of the double-base propellant and a weak interaction with RDX.
The burning rates of the two propellants were determined by using a Crawford bomb. The results showed that the burning rate
rises by about 19–66% when 23.5%DATH is substituted for RDX in a minimum smoke propellant. Meanwhile, the N2 level in the combustion gases is enhanced, which is valuable for a reduction of the signal level of the solid propellant.
The linear expansions of two materials have been measured, a double-base propellant and a carboxyl-terminated polybutadiene. The glass transition temperature,Tg and expansion coefficients below and aboveTg have been calculated. The influence of the heating and cooling rates and sample thickness has been investigated. The results show that the value ofTg is dependent on the rates of heating and cooling but not on the sample thickness. Extrapolating to zero rate gives the sameTg for both heating and cooling. The expansion coefficients are not influenced by the rates of heating and cooling or by the sample thickness.