Authors:C. Popescu, W. P. C. de Klerk, and E. L. M. Krabbendam-LaHaye
Summary Gun propellants are per definition instable substances. During their lifetime a slow decomposition process is going-on. During this decomposition process the heat that is generated accelerates the process, which could result to an unsafe situation, or an unexpected explosion of the material. The temperature to initiate the explosion of a propellant is of importance for the storage conditions of such a substance. The method used so far to evaluate this temperature is based on an extrapolation of the Kissinger equation at zero heating rate. A new proposal is the use of the invariant kinetic parameters (IKP) method to determine the iso-kinetic temperature and extrapolating it to zero heating rate as an alternative method. The results are discussed for some examples.
Authors:M. Batista, M. Ginani, D. Melo, and A. Oliveira
ZnS(1-x)MSx(x=0.01 and M=Mn2+, Cu2+ and Eu2+) compounds have been obtained by precipitation from homogeneous solutions of zinc, copper, manganese and europium salts,
with S2- as the precipitating anion, formed by the decomposition of thioacetamide. The thermal study of the milled zinc acetate, thioacetamide,
copper acetate, manganese acetate and europium nitrate, respectively, was studied for thermal analyis TG/DSC. XRD respect
exhibits a zinc blend crystal structure.
Authors:V. M. Abdul Mujeeb, K. Muraleedharan, M. P. Kannan, and T. Ganga Devi
fumes of bromine when heated to decomposition.
Information about the thermal stability of solid materials of all kinds is of great practical and technological importance [ 6 – 8 ]. Thermogravimetric
Thermal decomposition of borax has been researched by thermal, XRD and FTIR methods as well as SEM microscopy. Study have
revealed that it proceeds according to the mechanism of internal reactions in the structure of the precursor as a medium.
The following stages of the process have been distinguished: (1) dehydration, (2) internal structure reconstitution—formation
of tincalconite, (3) amorphization of crystal structure, (4) gradual dehydroxylation and crystallization of Na2O2B2O3 inside the amorphous matrix.
The Modified Entrainment Method developed by Faktor et al.  is an attractive yet not very popular method to determine vapour pressures in the range of 0.002 to 0.1 bar at 10–1000°C. The method consists of evaporating a solid or liquid from a small bulb through a capillary into a flowing inert gas, e.g. argon. The vapour pressure of the sample is related to the rate of evaporation and some easily controlled experimental parameters. In the present paper a new convenient experimental set-up is described and its use to study the decomposition of metal complexes is illustrated.
analysis of thermogravimetric curves. The calculations, based on multiple rates of thermogravimetric curves, are so-called iso-conversional calculation procedures [ 3 ].
Thermal decomposition of metal oxalates has been the subject of many researches
Authors:R. Frost, J. Kristóf, W. Martens, M. Weier, and E. Horváth
mineral sabugalite (HAl)0.5[(UO2)2(PO4)]2⋅8H2O, has been studied using a combination of energy
dispersive X-ray analysis, X-ray diffraction, dynamic and controlled rate
thermal analysis techniques. X-ray diffraction shows that the starting material
in the thermal decomposition is sabugalite and the product of the thermal
treatment is a mixture of aluminium and uranyl phosphates. Four mass loss
steps are observed for the dehydration of sabugalite at 48°C (temperature
range 39 to 59°C), 84°C (temperature range 59 to 109°C), 127°C
(temperature range 109 to 165°C) and around 270°C (temperature range
175 to 525°C) with mass losses of 2.8, 6.5, 2.3 and 4.4%, respectively,
making a total mass loss of water of 16.0%. In the CRTA experiment mass loss
stages were found at 60, 97, 140 and 270°C which correspond to four dehydration
steps involving the loss of 2, 6, 6 and 2 moles of water. These mass losses
result in the formation of four phases namely meta(I)sabugalite, meta(II)sabugalite,
meta(III)sabugalite and finally uranyl phosphate and alumina phosphates. The
use of a combination of dynamic and controlled rate thermal analysis techniques
enabled a definitive study of the thermal decomposition of sabugalite. While
the temperature ranges and the mass losses vary due to the different experimental
conditions, the results of the CRTA analysis should be considered as standard
data due to the quasi-equilibrium nature of the thermal decomposition process.
Authors:E. M. Schwartz, I. M. Vitola, G. S. Sergeiyeva, G. O. Piloyan, and O. V. Drozdova
The thermal decompositions of dicitratoborates M1[B(C6H6O7)2]·nH2O (n=0–2, M1=Rb, K, Li, NH4) and M11[B(C6H6O7)2]2·8H2O (M11=Co, Ni, Mn, Cu, Zn, Cd) were investigated by means of TG, DTA and DTG methods. It was found that these thermal decompositions involve three successive stages: dehydration, the endothermal decomposition of the ligand, and oxidation of the residual organic component. The volatile products of decomposition in each stage were detected by means of gas chromatography. The method of TG-curve transformation into the curvedm/d T vs.m, wherem is the loss of weight at each moment of time, was used for a more detailed study of dehydration. The optimal conditions for TG-curve modification were found.
Authors:Emma Jakab, Erika Mészáros, and Mária Omastová
The thermal stability of polypyrrole
(PPy) samples has been studied by thermogravimetry/mass spectrometry and pyrolysis-gas
chromatography/mass spectrometry in inert atmospheres. PPy has been prepared
by chemical oxidative polymerization using ferric sulfate as an oxidant and
anionic surfactants, such as dodecylbenzenesulfonic acid and sodium dodecylbenzenesulfonate
as co-dopants. For comparison we have studied polypyrrole (PPy-SO4)
prepared without any additive. It was found that the presence of anionic surfactants
improved the thermal stability of PPy. The decomposition of PPy doped with
ferric sulfate and anionic surfactants occurs at relatively high temperature
indicating that chemical interactions exist between the polymer and the surfactants.