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    Wyświetlanie 1-11 z 11
    Tytuł:
    Novel Composite Solid Propellant with High Resistance to Thermo-oxidative Degradation Reactions, Extended Shelf Life, and Superior Combustion Characteristics
    Autorzy:
    Elbasuney, Sherif
    Elsaka, Eslam
    Elbeih, Ahmed
    Mostafa, Hosam E.
    Powiązania:
    https://bibliotekanauki.pl/articles/27787864.pdf
    Data publikacji:
    2021
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    composite propellants
    ageing
    mechanical properties
    curing ratio
    combustion
    Opis:
    Hydroxy-terminated polybutadiene (HTPB) pre-polymer is the main constituent that is responsible for conferring high mechanical properties on composite solid propellants. However, HTPB pre-polymer suffers from oxidative degradation reactions that diminish its mechanical properties and shelf life. Composite solid propellant formulations based on an advanced stabilizing agent (anti-oxidant), Flexzone 6-H, with different curing ratios, 0.7 and 1.1, were developed via mixing and casting under vacuum. The developed formulations were subjected to artificial ageing using Vant Hoff,s formula by isothermal heating at 80 °C for up to 35 days. The change in strain with ageing was evaluated using a uni-axial tensile test. The propellant formulation based on a curing ratio of 0.7 demonstrated a high ageing resistance coefficient and an extended service life of up to 15 years, compared with 5 years for higher curing ratio. A propellant grain is considered to be ‘aged out’ at 30% reduction in its maximum strain value. The propellant formulation based on the 0.7 curing ratio exhibited superior thermal stability as it offered a minimum decrease in heat released after ageing using DSC. Additionally, the 0.7 curing ratio formulations exhibited a minimum change in burning rate and pressure exponent with ageing time. It can be concluded that the propellant with 0.7 curing ratio can maintain its mechanical, thermal, and ballistic properties with ageing.
    Źródło:
    Central European Journal of Energetic Materials; 2021, 18, 1; 143--158
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Application of Thin Layer Chromatography Combined with Optical Densitometry to Quantitative Analysis of Diphenylamine and Its Initial Daughter Reaction Products in Single-Base Propellants Aged under Natural Conditions
    Autorzy:
    Miszczak, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/358471.pdf
    Data publikacji:
    2011
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    TLC
    optical densitometry
    SB propellants
    DPA
    natural ageing
    Opis:
    Thin Layer Chromatography (TLC) was used for the quantitative measurement of the composition of stabilizers used to retard chemical decomposition of single-base (SB) propellants i.e. diphenylamine (DPA), and its initial reaction products due to natural ageing of these propellants under natural (ambient) conditions with test results and certain observations in this matter, are presented. The quantitative determination of DPA and its reaction products was possible by a combination of TLC with the densitometric spectrophotometry technique in the UV detection region. The crucial stage of TLC analytical quantitations was complete extraction of the substances to be analysed from SB propellants nitrocellulose (NC), which was done by rapid dissolution of the SB propellant samples followed by dilution of the solutions obtained to such degree as to make possible TLC separation of the substances to be analysed from the NC "matrix" in which they are "trapped" when the solution is too viscous. Initial chemical changes of DPA in SB propellants resulting in the appearance of DPA initial daughter reaction products such as N-nitroso-DPA, 2-nitro-DPA and 4-nitro-DPA, gave important information on the natural ageing of these homogeneous propellants starting from their very short storage period (some days, weeks or months just after their manufacture) up to long storage lasting even 50 years.
    Źródło:
    Central European Journal of Energetic Materials; 2011, 8, 2; 107-116
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Investigation of the Extended Storage of Single-base Propellants
    Autorzy:
    Nedkova, M.
    Shishkov, P.
    Varadinova, L.
    Glavchev, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/358213.pdf
    Data publikacji:
    2014
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    ageing
    single-base propellants
    elemental analysis
    FTIR
    swelling
    Opis:
    An investigation of single-base propellants has been conducted. The ageing process during extended storage of single-base propellants (SBP) in nonheated military stores and a heated building has been investigated by elemental analysis. Two or three different absorbencies around the band at 1650 cm-1 were observed by FTIR spectroscopy. In this way, not only the denitration of the propellants was determined, but also cleavage of -O-C- bonds between the glycoside rings in the nitrocellulose macromolecules. The latter process was confirmed by the swelling of the SBP.
    Źródło:
    Central European Journal of Energetic Materials; 2014, 11, 4; 613-624
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ageing Behaviour of HTPB Based Rocket Propellant Formulations
    Autorzy:
    Cerri, S.
    Bohn, M. A.
    Menke, K.
    Galfetti, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/358902.pdf
    Data publikacji:
    2009
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    solid rocket propellant
    HTPB
    nanoAl
    ageing
    mechanical properties
    Opis:
    The ageing of HTPB propellant formulations containing nanoAl is investigated. During natural ageing the material undergoes a series of slow physico-chemical degradation reactions. By using accelerated ageing conditions it is possible to simulate the material behaviour at different time-temperature conditions especially focused on the in-service conditions. The mechanical and ageing behaviour of aluminised solid rocket propellants were investigated in terms of uniaxial tensile strength, DMA measurements, impact and friction sensitivity tests, SEM analyses.
    Źródło:
    Central European Journal of Energetic Materials; 2009, 6, 2; 149-165
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of Mechanical Properties of Naturally Aged Double Base Rocket Propellants
    Autorzy:
    Sućeska, M.
    Matečić Mušanić, S.
    Fiamengo, I.
    Bakija, S.
    Bakić, A.
    Kodvanj, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/357946.pdf
    Data publikacji:
    2010
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    mechanical properties
    rocket propellant
    natural ageing
    dynamic mechanical analysis
    tensile test
    Opis:
    Various chemical reactions and physical processes (such as stabilizer consumption, migration and evaporation of nitroglycerine, decomposition of nitroglycerine and nitrocellulose, etc.) take place in double based rocket propellants grains over the time, even under ambient storage conditions. The overall effect of these reactions and processes are changes of physical, chemical, thermal, ballistic and mechanical properties of rocket propellants with storage time, i.e. the reduction of the propellants performances and safe service life. The aim of this work was to evaluate the mechanical changes of rocket propellants – sustainers, built in in-service antitank guided missiles systems, induced by natural ageing at ambient conditions during up to 35 years of storage. The mechanical and viscoelastic properties were tested using a dynamic mechanical analyser, an uniaxial tensile and compression tester, and a notch toughness tester. The results have shown that the changes of the studied mechanical and viscoelastic properties are evident, although the results of the tests are rather scattered (as a consequence of measuring uncertainty, different ageing histories of propellants, etc.) or changes of some properties are not too pronounced. For example, after 15 years of storage at ambient conditions the glass transition temperature increases for about 5 C, the tan δ in the glass transition region decreases for about 5%, the storage and loss modulus at 25 °C increase for about 15%, Young modulus at 23 C increases up to 30%, the notch toughness at -30 C decreases up to 15%, etc. Along with these tests, the stabilizer content determination and proving ground ballistic tests were also done.
    Źródło:
    Central European Journal of Energetic Materials; 2010, 7, 1; 47-60
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    UV-VIS and FTIR Investigations of Long-Term Aged Explosives. Part 2
    Autorzy:
    Shishkov, P.
    Nedkova, M.
    Atanasova, P.
    Glavchev, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/358669.pdf
    Data publikacji:
    2011
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    long-term ageing
    TD-50
    tetryl
    UV-VIS
    FTIR
    H-bond
    Opis:
    Samples of long-term aged TD-50 and tetryl were investigated by UV-VIS and FTIR spectroscopy and bands of products of ageing were obtained. A complicated maximum of nitro groups at 1537 cm-1 in the FTIR spectra of long-term aged explosives was obtained, like in the IR spectra of long-term aged single-based propellants. Ageing process was confirmed by the presence of several maxima in UV-VIS and FTIR spectra of aged products and determination of several characteristics of the investigated explosives (shifts Δ ν, differences in absorbances ΔA, differences in values of Δh*1/2). Ageing was connected with decrease of H-bond formation on the base of decrease of content of oxygen and nitro groups in TD-50 and tetryl.
    Źródło:
    Central European Journal of Energetic Materials; 2011, 8, 4; 303-310
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Assessment of the Shelf Life of Composite Solid Propellants in Air and Nitrogen Atmospheres through Thermal Ageing
    Autorzy:
    Keshavarz, Mohammad Hossein
    Hosseini, Seyyed Hesamodin
    Mehran, Karimi
    Powiązania:
    https://bibliotekanauki.pl/articles/27787850.pdf
    Data publikacji:
    2021
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    composite solid propellant
    inert atmosphere
    dynamic mechanical thermal analysis
    DMTA
    damping
    ageing
    Opis:
    This work introduces dynamic mechanical thermal analysis (DMTA) as an efficient method for the assessment of the shelf life of solid composite solid propellants in air and nitrogen atmospheres. The samples were aged at three temperatures 323.15, 333.15, and 343.15 K for 60, 120, and 180 days. The two different methods of Arrhenius and Berthelot were used to compare the effects of air and nitrogen atmospheres on the ageing of composite solid propellants. Damping (Tan δ) of composite solid propellants was used to determine the shelf life of the samples based on the loss of half of the physical property Tan δ (50% drop in damping). For the air atmosphere, the calculated activation energy for the degradation reactions of the samples was 86.26 kJ·mol–1. Both models, Arrhenius and Berthelot, confirmed that the shelf lives of the samples under the nitrogen atmosphere are more than four times those in an air atmosphere.
    Źródło:
    Central European Journal of Energetic Materials; 2021, 18, 1; 25--45
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mechanical and Ballistic Properties of Spherical Single Base Gun Propellant
    Autorzy:
    Boulkadid, K. M.
    Lefebvre, M. H.
    Jeunieau, L.
    Dejeaifve, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/357976.pdf
    Data publikacji:
    2017
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    mechanical properties
    firing temperature
    gun propellant
    ageing
    ballistic firing
    closed vessel tests
    Opis:
    The effect of the initial temperature on the mechanical properties of spherical single base gun propellant was investigated by means of a compression test, which consisted of compression of a propellant bed conditioned at various initial temperatures. Following this mechanical treatment, the pressed grains (after thermal conditioning at ambient temperature) were tested in a closed vessel. The results from the combination of compression and closed vessel tests supported the assumption that there are two phenomena occurring inside the cartridge at low temperatures which compensate each other; the first is a decrease in the burning rate as the initial temperature is decreased, and the second is grain fracturing occurring on ignition. Additionally, a specific parameter, the specific surface area, turns out to be an appropriate parameter for quantifying the mechanical damage to the propellant grain resulting from the compression test. Tests on the aged propellant have also been conducted.
    Źródło:
    Central European Journal of Energetic Materials; 2017, 14, 1; 90-104
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Temperature Sensitivity of Propellant Combustion and Temperature Coefficients of Gun Performance
    Autorzy:
    Boulkadid, M. K.
    Lefebvre, M. H.
    Jeunieau, L.
    Dejeaifve, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/358071.pdf
    Data publikacji:
    2016
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    firing temperature
    temperature sensitivity
    temperature coefficient
    ball propellant
    ageing
    ballistic firing
    closed vessel tests
    Opis:
    One of the objectives of gun propellant research is to develop green formulations of gunpowder that should be less temperature sensitive than the current gun propellant. The temperature sensitivity of these new green formulations of the propellant should be measured to identify the less temperature sensitive green formulations. However, there are deficiencies in the methodologies for the measurement of the temperature sensitivity of gun propellants. Therefore, the aim of this investigation was to fill the gap by establishing a method for the measurement of the temperature sensitivity of deterred gun propellants by closed vessel tests. The temperature sensitivity of the burning rate of ball propellants and the temperature coefficients of gun performance were determined using closed vessel tests and ballistic firing, respectively. Specific definitions of temperature sensitivity and temperature coefficients were evaluated. The relation between these parameters has never been explicitly investigated previously. Assessing the temperature sensitivity of propellants by closed vessel tests is of added value to the range of ballistic tests if the results of these tests can be well correlated to the results of ballistic firings. Therefore, a comparison between both parameters was made. A correspondence has been observed between the temperature sensitivity of the propellant burning rate, as obtained from closed vessel tests, and the temperature coefficients as obtained from ballistic firings.
    Źródło:
    Central European Journal of Energetic Materials; 2016, 13, 4; 1005-1022
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dynamic Mechanical Properties of Artifcially Aged Double Base Rocket Propellant and the Possibilities for the Prediction of Their Service Lifetime
    Autorzy:
    Matečić-Mušanić, S.
    Sućeska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/358886.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    ageing
    double base rocket propellants
    dynamic mechanical analysis
    glass transition temperature
    lifetime prediction
    loss modulus
    softening temperature
    storage modulus
    tan δ
    Opis:
    The ageing of double base (DB) rocket propellants, as a consequence of the chemical reactions and physical processes that take place over time, has a signifcant effect on their relevant properties, such as chemical composition and mechanical and ballistic properties. The changes to relevant properties limit the safe and reliable service life of DB rocket propellants. Accordingly, numerous research efforts have been undertaken to fnd reliable methods to measure the changes caused by ageing in order to assess the quality of DB rocket propellants at a given moment of their lifetime, and to predict their remaining service lifetime. In this work we studied the dynamic mechanical properties of DB rocket propellant artifcially aged at temperatures of 80, 85 and 90 °C, in order to detect and quantify changes in the dynamic mechanical properties caused by ageing, and to investigate the possibilities for the prediction of service lifetime. Dynamic mechanical properties were studied using a dynamic mechanical analyser (DMA). The results obtained have shown that ageing causes signifcant changes in the storage modulus (E´), the loss modulus (E˝) and the tan δ curves’ shape and position. These changes are quantifed by following some characteristic points on the E´-T, E˝-T, and tan δ-T curves (e.g. glass transition temperatures; storage modulus, loss modulus and tan δ at characteristic temperatures, etc.). It has been found that the monitored parameters are temperature and time dependent, and that they can be shown to be functions of the so called ‘reduced time of artifcial ageing’. In addition, it has been found that, on the basis of known changes in viscoelastic properties as a function of time and ageing temperature, and the known kinetic parameters of the ageing process, it is possible to calculate (determine) the change in the properties at any ageing temperature provided that the mechanism of the ageing process does not change. Unfortunately, the use of kinetic parameters obtained by artifcial ageing at high temperatures (above 60 °C) for the prediction of the propellant lifetime will not give reliable results, because the mechanisms of ageing at 85 °C and 25 °C are not the same.
    Źródło:
    Central European Journal of Energetic Materials; 2013, 10, 2; 225-244
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Applicability of Chromatographic Methods in the Investigation of Ageing Processes in Double Base Rocket Propellants
    Autorzy:
    Matečić-Muśanić, S.
    Sućeska, M.
    Čuljak, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/358695.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    activation energy
    artifcial ageing
    DB rocket propellants
    decomposition
    Ethyl Centralite (EC)
    Gel Permeation Chromatography (GPC)
    High Performance Liquid Chromatography (HPLC)
    kinetics of degradation
    mean molecular mass of NC
    Opis:
    The ageing of double base (DB) rocket propellants is the result of chemical decomposition reactions and physical processes, causing degradation of a number of relevant propellant properties (such as reduction in stabilizer and nitroglycerine (NG) content, reduction of the mean molecular mass of nitrocellulose (NC) etc.), which is refected in a decrease in the reliable service life time of DB propellants. This is the reason why the study of processes of ageing and their consequences (effects) is so important. In this paper we have studied the kinetics of DB rocket propellant decomposition during their artifcial ageing, i.e. at elevated temperatures. The kinetic parameters were obtained by measurements of the stabilizer/Ethyl Centralite (EC) content and the mean molecular mass reduction of NC, during artifcial ageing at temperatures of 80, 85 and 90 °C. Consumption of the EC was observed using High Performance Liquid Chromatography (HPLC), whilst the reduction in the mean molecular mass of NC was monitored using Gel Permeation Chromatography (GPC). It has been shown that artifcial ageing of DB propellant causes signifcant EC consumption and a reduction in the mean molecular mass of NC, from the very beginning of ageing. EC is entirely consumed after 120 days at 80 °C, and is followed by the intensive reactions of NC decomposition. Signifcant changes in the mean molecular mass of NC starts after 60 days of ageing at 90 °C (or ~250 days at 80 °C). The results obtained from the kinetic data have shown that the activation energy of DB propellant decomposition, determined on the basis of changes in the mean molecular mass of NC is 145.09 kJ•mol-1 , whilst the activation energy of decomposition obtained on the basis of EC consumption is 142.98 kJ•mol-1 , which is consistent with available literature values [1, 2].
    Źródło:
    Central European Journal of Energetic Materials; 2013, 10, 2; 245-262
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-11 z 11

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