Authors:G. Singh, B. Baranwal, I. Kapoor, D. Kumar, C. Singh, and R. Fröhlich
Three hexamethylenetetramine (HMTA) metal nitrate complexes such as [M(H2O)4(H2O-HMTA)2](NO3)·4H2O (where M=Co, Ni and Zn) have been prepared and characterized by X-ray crystallography. Their thermal decomposition have been studied
by using dynamic, isothermal thermogravimery (TG) and differential thermal analysis (DTA). Kinetics of thermal decomposition
was undertaken by applying model-fitting as well as isoconversional methods. The possible pathways of thermolysis have also
been proposed. Ignition delay measurements have been carried out to investigate the response of these complexes under condition
of rapid heating.
Authors:Dumitru Oancea, Valentin Munteanu, Domnina Razus, and Maria Mitu
an S-shaped form, similar to the well-known conversion versus temperature variation (light-off curve) [ 26 ]. The recorded curves for the stoichiometric propane/air mixture have been used to measure the ignitiondelays and the steady-state reaction
The chemical stability of a propellant and its influence on the ballistic properties during aging is a subject of interest.
The effect of aging on ballistic properties, viz., ignition delay, burning rate, and heat of combustion for an aluminised
ammonium perchlorate–hydroxyl-terminated polybutadiene (AP/HTPB) composite propellant during accelerated aging were investigated.
Samples of composite propellants were aged at 60 and 70 °C at relative humidity of 50% in a climatic chamber. The propellant
samples were tested with pressurized nitrogen gas environment for ignition delay measurement. Test results indicate that aging
does not have any appreciable effect on ignition delay. The change in ignition delay time is less than 3% within the scatter
of the data. Experiment results indicate that burn rate do affect with pressure but aging does not have much effect on burn
rate. It was also observed that the burning rate at low pressures did not undergo significant changes during the aging period.
The most significant of all the ballistic properties of this propellant is the burning rate exponent which increased by about
10% during the aging period.
The nitrate complexes of copper, nickel and zinc with diethylenetriamine (dien) i.e. [Cu(dien)2](NO3)2, [Ni(dien)2](NO3)22H2O and [Zn(dien)2](NO3)2 have been prepared and characterised. Thermal studies were undertaken using TG-DTG, DSC, ignition delay (tid) and ignition temperature (IT) measurements. Impact sensitivity was measured using drop mass technique. The kinetic parameters for both non-isothermal
and isothermal decomposition of the complexes were evaluated by employing Coats-Redfern (C-R) method and Avrami-Erofeev (A-E)
equations (n=2 and 3), respectively. The kinetic analysis, using isothermal TG data, was also made on the basis of model free isoconversional
method and plausible mechanistic pathways for their decomposition are proposed. Rapid process was assessed by ignition delay
measurements. All these complexes were found to be insensitive towards impact of 2 kg mass hammer up to the height limit (110
cm) of the instrument used. The heat of reaction (?H) for each stage of decomposition was determined using DSC.
Two bis(bipyridine) polymeric metal nitrate complexes
with 4,4’-bipyridine of simple formula like [M(bipy)2](NO3)2⋅xH2O (where M=Co, Ni and Cu; x=4, 2 and 0, respectively) have been prepared and
characterized. Their thermal decomposition has been undertaken using simultaneous
TG-DTG-DTA and DSC in nitrogen atmosphere and non-isothermal TG in air atmosphere.
Isothermal TG has been performed at decomposition temperature range of the
complexes to evaluate the kinetics of decomposition by applying model-fitting
as well as isoconversional method. Possible mechanistic pathways have also
been proposed for the thermolysis. Ignition delay measurements have been carried
out to investigate the response of these complexes under the condition of
During the past several years, a significant effort has been on investigation of reaction front propagation and the rate of
energy release in heterogeneous systems consisting of nanopowder reactants. Substantial size reduction of each reactant powder
(e.g. from micro- to nano-size) leads to increase of reaction front propagation in some systems under unconfined conditions
by approximately two to three order of magnitude. This paper presents key challenges associated with processing and use of
nanothermite materials and characterization of nanoreactants. Reaction constants, such as activation energies and frequency
factors were determined using DSC technique for several nanothermite systems based on nanosize aluminum and iron oxide, bismuth
trioxide, and molybdenum trioxide. Experimental data of ignition delay times for different nanothermite systems using laser
energy source were compared well to those predicted by proposed mathematical model.
Authors:F. Lujaji, A. Bereczky, L. Janosi, Cs. Novak, and M. Mbarawa
); fuel injection pressure 10.3 MPa. The ignitiondelay was set to 13° by adjusting the compression ratio, so that combustion started at top dead centre (TDC) as specified by the American Society for Testing Materials (ASTM) 613. Table 1 shows the engine
Authors:Dumitru Oancea, Valentin Munteanu, and Domnina Razus
The induction period (or ignitiondelay) τ i , measured between ≈150 ms and several seconds, depends on mixture composition, its total pressure p 0 , and wire temperature T w . A simple relationship giving the analytical form