Kinetic parameters of the decomposition of hazardous chemicals can be applied for the estimation of their thermal behavior under any temperature profile.Presented paper describes the application of the advanced kinetic approach for the determination of the thermal behavior also under adiabatic conditions occurring e.g.in batch reactors in case of cooling failure.The kinetics of the decomposition of different samples（different manufacturers and batches） of 3-methyl-4-nitrophenol were investigated by conventional DSC in non-isothermal（few heating rates varying from 0.25 to 8.0K/min） and isothermal（range of 200~260℃） modes.The kinetic parameters obtained with AKTS-Thermokinetics Software were applied for calculating reaction rate and progress under different heating rates and temperatures and verified by comparing simulated and experimental signals.After application of the heat balance to compare the amount of heat generated during reaction and its removal from the system,the knowledge of reaction rate at any temperature profiles allowed the determination of the temperature increase due to the self-heating in adiabatic and pseudo-adiabatic conditions.Applied advanced kinetic approach allowed simulation the course of the Heat-Wait-Search（HWS） mode of operation of adiabatic calorimeters.The thermal safety diagram depicting dependence of Time to Maximum Rate（TMR） on the initial temperature was calculated and compared with the results of HWS experiments carried out in the system with Ф-factor amounting to 3.2.The influence of the Ф-factor and reaction progress reached at the end of the HWS monitoring on the TMR is discussed.Presented calculations clearly indicate that even very minor reaction progress reduces the TMRad of 24h characteristic for a sample with initial reaction progress amounting to zero.Described estimation method can be verified by just one HWS-ARC,or by one correctly chosen ISO-ARC run of reasonable duration by knowing in advance the dependence of the TMR on the initial temperature for any Ф-factor.Proposed procedure results in significant shortening of the measuring time compared to a safety hazard approach based on series of ARC experiments carried out at the beginning of a process safety evaluation.

Propellants can burn so rapidly that the initial rise of pressure in weapons may be faster than desired. To avoid this unwanted effect, burning rate of the propellants is moderated by applying a surface coating. Coating agents are usually deterrents (moderants), substances that gelatinize or plasticise the nitrocellulose matrix of the propellants decreasing its initial burning rate, therefore, in turn, the rate of gaseous phase formation. The knowledge of the diffusion rate of deterrents helps therefore in developing propellants with superior ballistic performance. Another parameter, namely the rate of the migration of deterrent into the propellant matrix during ageing / storing is also important as it influences the ballistic shelf-life i.e. the period of time during which the ballistic requirements are fulfilled. As migration measurements are often difficult, expensive and timeconsuming the development of the simulation tools of above processes seems to be of a great importance. The present paper describes the simulation method for deterrent and blasting oil diffusion in double base propellant applying the temperature dependence of the diffusion coefficients D determined in isothermal experiments and taking into account the influence of the swelling effect of the propellant matrix. The simulations were done using the AKTS-SML software [1], which allowed considering the migration of both, deterrent and nitroglycerine through the swollen matrix of the propellant. Furthermore, after determination of the temperature dependence of the diffusion coefficient D, it was possible to predict the deterrent migration under any, arbitrarily chosen temperature profile such as oscillatory temperature mode, real atmospheric temperature profiles or under temperature mode corresponding to atmospheric changes according to STANAG 2895 [2].

The exothermic decomposition parameters of a single-base propellant were obtained using differential scanning calorimeter (DSC) tests conducted at various heating rates. The DSC signals were processed using the Friedman isoconversional method to compute activation energy as a function of conversion. There was excellent agreement between the experimental and the simulation plots, which confirms the validity of the kinetic model used to describe the propellant’s exothermic decomposition. The kinetic parameters and heat balance were subsequently analyzed and used for a simulation of cookoff experiments conducted at different experimental rates (heating rates 3.3 1.0 K/h and a heat-waitsearch mode). This study presents a simulation of the propellant’s adiabatic behaviour Time to Maximum Rate (TMR) under adiabatic conditions (TMRad) and self-accelerating decomposition temperature (SADT). This study also illustrates and discusses the effect of a material’s thermal conductivity on the time to ignition at various heating modes. INTRODUCTION The method of the prediction of the thermal behaviour of the energetic materials such as temperature and time to the ignition during cook-off experiments or simulation of SADT strongly depends on the sample mass due to the significant influence of the heat generated during the reaction course. At the mg-scale, all the evolved heat dissipates to the surroundings and does not affect the temperature of the heated material. Whereas at the ton-scale, the system can be considered adiabatic, because almost all generated heat remains in the sample and there is the potential for a thermal runaway decomposition. From a practical perspective for the kg-scale, the temperature change of the test material results from two different processes that together determine the heat balance, which is defined by the heat generated during the thermal decomposition and heat loss to the environment. The rate of heat generated during an exothermic decomposition increases exponentially as the temperature rises but the rate of the heat loss occurs in a linear manner. Therefore, in order to properly predict the thermal decomposition behaviour of an energetic material, there must be a precise understanding of the kinetic parameters because their knowledge is the prerequisite for the correct description of the heat generation rate and heat balance of the system. There are two critical factors which have to be considered during the simulations: (i) The intrinsic properties of the test material, i.e., the kinetic parameters of the decomposition (activation energy, pre-exponential factor in the Arrhenius equation) and the physical-chemical properties such as the thermal conductivity, specific heat and density which cannot be changed. (ii) The external properties of the sample, i.e., the sample mass, the geometry of the sample holder, container or the reactor, and, finally, the heating mode applied during the experiment or simulation (slow or fast cook-off, heat-wait-search mode, isothermal or adiabatic run) which can be changed arbitrarily. It is known that changes to the external properties or experimental conditions can significantly influence the course of the decomposition process. For example it was reported that the change of the heating rate during cook-off experiment changes the location of the ignition point in the sample. By increasing the heating rate the decomposition moves from the inner to outer shell of the material (1, 2). It is also known (3) that accurate simulation of time/temperature of cook-off for low temperatures and slow heating rates are more difficult than for higher temperatures and heating rates. One of the main factors responsible for these complications is the thermal conductivity of the material. The objective of this paper was to determine how the simulation of the cook-off parameters (time and temperature of the ignition) can be influenced by the thermal conductivity (λ) of the sample for the heating mode applied. Preliminary experiments show that lowering the heating rate has more of an impact of the λ on the cook-off ignition time. Therefore additional simulations were performed to determine the influence of λ during boundary conditions when the heating rate is = 0, i.e., under the isothermal conditions required for the simulation of SADT. Finally, the simulations of the material properties under adiabatic conditions (Time to Maximum Rate, TMRad) were performed. EXPERIMENTAL The present study contains the experimental results and simulations of the properties of the singlebase propellant. The kinetic parameters required for the simulation were calculated from the DSC traces applying AKTS-Thermokinetics Software (4). The DSC experiments were carried out in sealed crucibles (5) from room temperature till 260°C with various heating rates. The cook-off experiments were carried out in cylindrical steel tube with: ID 47 mm, length 200 mm, wall thickness 4 mm and the volume of 0.35L (armasuisse in-house construction) equipped with three thermo elements. Three temperature modes were chosen for experiments and simulations: hold temperature 40°C, hold time 7h followed by the temperature ramp of 3.3 K/h according to STANAG 4383, hold temperature 100°C, hold time 9h followed by the 1 K/h temperature ramp, heat-wait-search mode (H-W-S) similar to those applied in Accelerating Rate Calorimetry. In this mode the sample was heated to the pre-selected initial temperature 109°C, slightly lower than the ignition temperature recorded during the slower cook-off (1K/h) experiment, and held a period of time (1.8 days) to achieve thermal equilibrium. A search was than conducted to measure the rate of heat gain (self-heating) of the sample. If the rate of self heating was so slow that the temperature of the sample stayed constant, the temperature was increased by 4K and the heat-wait-search sequence was repeated. This routine was continued until the significant temperature jump was observed. The experimental setup is presented in Figure 1. Figure 2 shows the damaged tubes after cook-off experiments, the fragment size and number give the qualitative information on the violence level. Fig. 1 Experimental setup of the cook-off experiment Fig. 2 Cook-off steel tubes after the experiments carried out with three temperature modes described above. From left to right: temperature ramp 3.3 K/h, temperature ramp 1.0 K/h and heat-wait-search mode. EVALUATION OF THE DECOMPOSITION KINETICS The evaluation of the kinetics of the decomposition of energetic materials is one of the main prerequisites necessary for the correct modelling of their properties. Generally, the kinetic parameters are calculated from the experimental data obtained by means of thermoanalyzers or calorimeters such as e.g. TG, DTA or DSC signals. In DSC, the most commonly applied thermal analysis technique for examining energetic materials, the determination of the kinetic parameters from the recorded signal requires its integration in order to obtain the α-time or -temperature relationship necessary for kinetic calculations. The course of the baseline can significantly influence the determination of the heat of the reaction and the estimation of the α-T dependence. The very important feature of the AKTSThermokinetics Software (4) is the possibility of the optimization of the baseline for all experiments collected by different heating rates (or temperatures) so that the random errors in the various baseline constructions for all heating rates will “average themselves out”. If the decomposition follows a single kinetic model then the reaction can be described in terms of a single pair of Arrhenius parameters and the commonly used set of functions f(α) reflecting the mechanism of the process. In such a case the dependence of the logarithm of the reaction rate over 1/T is linear with the constant slope m = E/R in full range of conversion degree α. The reaction rate can be described by only one value of the activation energy E and one value of the pre-exponential factor A by the following expression: ) f( RT(t) E exp A dt d α α       − = (1) where t is time, T temperature, Rthe gas constant, E the activation energy, Athe pre-exponential factor, α is the fraction converted and f(α) is a differential form of the conversion function depending on the reaction model. However, the decomposition reactions are generally too complex to be described in terms of a single pair of Arrhenius parameters (A and E) and the commonly applied set of reaction models f(α). In general, decomposition reactions demonstrate profound multi-step characteristics. The assumption that the decomposition of an energetic material will obey a simple rate law is very rarely true. Moreover, the determination of the kinetic parameters from the single run recorded with one heating rate only (so called ‘single curve’ method) leads to erroneous results and according to the recent recommendations should not be applied anymore (6,7). In the present paper the kinetic parameters have been calculated by the isoconversional method of Friedman (8) based on the calculation of E and A values at different degrees of conversion α without assuming the form of f(α) function, i.e. applying logarithmic form of the following reaction rate expression : { }       − = ) RT(t E exp ) f( A dt d

The exothermic decomposition parameters of a single-base propellant were obtained using differential scanning calorimeter (DSC) tests conducted at various heating rates. The DSC signals were processed using the Friedman isoconversional method to compute activation energy as a function of conversion. There was excellent agreement between the experimental and the simulation plots, which confirms the validity of the kinetic model used to describe the propellant's exothermic decomposition. The kinetic parameters and heat balance were subsequently analyzed and used for a simulation of cook-off experiments conducted at different experimental rates (heating rates 3.3 - 1.0 K/h and a heat-wait-search mode). This study presents a simulation of the propellant's adiabatic behaviour Time to Maximum Rate (TMR) under adiabatic conditions (TMRad) and self-accelerating decomposition temperature (SADT). This study also illustrates and discusses the effect of a material's thermal conductivity on the time to ignition at various heating modes.

Ammonium dinitramide is planned to be a substitute for commonly used oxidizers in rocket motor compositions. Different teams worldwide have already synthesized alkali salts of dinitramide and several times it was used as an oxidizer for pyrotechnic compositions containing boron as a reducing agent. In this paper the results of a systematic investigation to characterize the pyrotechnic redox systems titanium/potassium dinitramide and titanium/cesium dinitramide are presented and the data are compared. The heats of reaction as well as the burning rates of the redox system titanium/potassium dinitramide are higher than those of the redox system titanium/cesium dinitramide. Both systems show a moderate sensitivity to friction and electrostatic discharges. However the sensitivity of mixtures of both redox systems shows a very high sensitivity to impact. These sensitivities are in the range of pure HMX or pentaerythritol tetranitrate.

Starting from commercially available ammonium dinitramide (ADN), which was dissolved either in water or in methanol, the sodium, potassium, rubidium and cesium dinitramide were synthesized in yields > 70 % by adding the corresponding alkali metal hydroxide. The basic equation for the reaction is the following: NH4N(NO2)(2) + MOH -> MN(NO2)(2) + H2O + NH3 M = Na, K, Rb, Cs The crystallization was carried out of a highly concentrated water solution or of methanol. The procedure of a crystallization out of a water solution was not applicable for the very hygroscopic NaN(NO2)(2) compound. It could only be crystallized by using the freeze-drying method. ne dinitramide salts were characterized by determing the melting point, by elemental analysis, by Differential-Scanning-Calorimetry (DSC), Thermal-Gravimetry-Analysis (TGA), IR-Spectroscopy and by light microscopical investigations of the crystal shape. The results are in good agreement with the values mentioned in literature. However the DSC and TGA measurements show some significant differences to already published results. The X-ray structure analysis of RbN(NO2)(2) shows an isomorphic structure in comparison to CsN(NO2)(2).

Phenomena (reaction effects) such as varied light emissions, sound, varied burning rates, varied heats of reaction and reaction products occur during the reaction of inorganic redox systems used for pyrotechnics. The peculiarity of these redox reactions is, that they take place as solid-solid, solid-liquid or solid-gaseous state reactions. In opposite the theoretical redox reaction normally postulated in inorganic chemistry takes place in a solvent. By variation of different parameters as for example the reducing agent, the oxidizer, the oxygen balance and the particle size, it is possible to create the above-mentioned effects in a wide range.

The paths artificial fireworks took from China to Europe and the subsequent development of such fireworks from religious miracles to exciting entertainment for spectators is shown. Some basic information about fireworks is presented. By using auxiliary substances, it is possible to produce differently colored light or smoke. The procedure to prepare a commercial firework display is described. Some of the most important articles and items used in firework displays are listed.

Phenomena such as varied light emissions, sound, burning rates, heats of reaction and reaction products occur during inorganic redox reactions. The peculiarity of these redox reactions is that they take place as solid–solid, solid–liquid or solid–gas state reactions and not as redox reactions in a solvent as normally postulated in inorganic chemistry. By variation of different parameters such as the reducing agent, the oxidizer, the oxygen balance or the particle size, it is possible to create a wide range of the above-mentioned effects.

Around the time that Switzerland was established, the use of black powder or gun powder was also mentioned for the first time in this area. For the following five hundred years black powder was the only explosive known in Switzerland. The performance of black powder depended very much on the production process. In the 19th century, Prof. Schönbein synthesized the new energetic material cellulose nitrate at the University of Basel. Also in the 19th century the use of fireworks in Switzerland was mentioned for the first time. During World War I a new cellulose nitrate propellant plant was built in Wimmis. Today, new energetic materials which are not available commercially are synthesized and characterized in the laboratories of armasuisse.

The critical temperature-time regime of the self-ignition of energetic ammunition systems is usually investigated by elaborated experimental setups, e.g. in the EIDS slow cook-off the sample is heated with a rate of 3.3°C/h in a steel container. The results collected in such experimental setups can be successfully simulated by applying kinetic parameters obtained from non-isothermal isochoric experiments (closed crucibles) performed on any commercial Differential Scanning Calorimetry (DSC) system. During modeling two important factors have to be considered: (i) the application of advanced kinetics, which properly describes the complicated, multistage course of the decomposition process and (ii) the effect of heat balance in the energetic ammunition system, as the sample mass is increased by a few order of magnitude compared to the thermoanalytical DSC experiments. The correct accumulation of heat for large sample masses can be calculated by applying Finite Element Analysis (FEA) methods as described by us in (1-2). The results of modeling have been verified by the comparison with the experimentally determined values of the time to ignition for single base propellant being used in 5.56 mm small caliber system and a new 155 mm artillery charge for the Swiss army under isothermal conditions. For the artillery charge the simulations have been done for the sample being in the form of cylinder containing three layers of the materials possessing significantly different thermal properties, namely single- base propellant, combustible cartridge case and steel container. The very good prediction of the experimental results indicates the high accuracy of the applied method. Evaluation of kinetics The evaluation of the kinetics of the decomposition of energetic materials is one of the main prerequisites necessary for the correct modelling of their properties. Generally, the kinetic parameters are calculated from the experimental data obtained either from thermogravimetry (change of the mass, TG) or differential thermal analysis (monitoring thermal effects, DSC or DTA). Independent of the experimental technique applied, the kinetic calculations require the dependence of the reaction extent α on the time or temperature. Calculations of the reaction progress are much easier from TG data and require only the correction of the signal due to the buoyancy phenomena. More complicated is the determination of the relationship α-T from DSC (DTA) traces because it requires the integration of the signals influenced by the construction of the baseline.