Thermal decomposition kinetics of PBAN-binder and composite solid rocket propellants (original) (raw)
Related papers
1998
Jphl 7 2 1997 O S T I mmonium perchlorate (AP) and ammonium-Derchlorate-based comDos te propellants are studied using the simultaneous the&ogravime&c modulated beam mass spectrometry (Sll&MS) technique. The main objective of the present work is to evaluate whether the STMBMS can provide new data on these materials that will have sufficient detail on the reaction mechanisms and associated reaction kinetics to permit creation of a detailed model of the thermal decomposition process. Such a model is a necessary ingredient to engineering models of ignition and "slow-cookoff ' for these AP-based composite propellants. Our results show that the decomposition of pure AP is controlled by two processes. One occurs at lower temperatures (240OC to 27OoC), produces mainly H20, 02, Cl,, N,O and HCl, and is shown to occur in the solid phase within the A p particles. 200p diameter AP particles undergo 25% decomposition in the solid phase, whereas 20p diameter AP particles undergo only 13% decomposition. The second process is dissociative sublimation of AP to NH, + HClO, followed by the decomposition of, and reaction between, these two products in the gas phase. The dissociative sublimation process occurs over the entire temperature range of AP decomposition, but only becomes dominant at temperatures above those for the solid-phase decomposition. The results on the thermal decomposition of the AP-based composite propellant show several different features. First, the features of the two processes associated with the decomposition of the pure AP are still evident in the decomposition of the propellant. However, the oxidative products that evolve from the AP, such as O,, C1, and HClO,, react to various extents with the plasticizer and binder in the propellant. The evolution rates of the gaseous products from the propellant sample, formed from the decomposition of AP within the propellant, are reduced compared to their evolution rates from pure AP. This reduced rate of evolution may be due initially to diffusionlimited flow of gas out of the sample, and at later stages, due to r e d u d flow through channels created by decomposition of the Ap and binder. The reaction of the binder with HClO, occurs in a two-step sequence. First, most of the hydrogen is removed from the binder, then the remaining carbonaceous residue reacts with the oxidizers formed in the dissociative-sublimatiodgas-phase reactions of AP to form CO and CO,. The results show that the STMBMS technique can be used to provide very detailed quantitative data on the decomposition of both pure AP and AP-based composite propellants. It appears that data of sufficient detail can be obtained that will allow a detailed engineering model of the thermal decomposition process to be created. Such a model will permit prediction of: the extent of decomposition of AP, plasticizer and binder; the identities and quantities of the gaseous reaction products; and the porosity and flow characteristics of the propellant as a function of time and temperature. Inclusion of these data in a 3D thermochemical code should allow the state of an AP-based composite propellant grain to be predicted when subjected to a thermal event, such as a fire. 0 a-* Work supported by a Memorandum of Understanding between the U.S. Department of Energy and the Office of Munitions and by the U.S. Department of Energy under contract DE-AC04-94AL85000 tWRK3~~hl OF THIS bOCUMEbif IS UNLIM~EQ MA DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or P~OCPSS disdosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, p m s , or service by trade name, trademark, manufacturer, or otherwise does not necessarily cons!jtute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. ' Behrens and Minier AP-based Propellant Decomposition , Behrens and Minier AP-based Propellant Decomposition the final products, CI,, NO, O,, and H,O (step 5). Note that the higher temperature channel is observed to form NO rather than N,O as observed in the lower temperature channel.
Thermal degradation of a composite solid propellant examined by DSC
Journal of Thermal Analysis and Calorimetry, 2000
The thermal decomposition of ammonium perchlorate (AP)/hydroxyl-terminated-polybutadiene (HTPB), the AP/HTPB solid propellant, was studied at different heating rates in dynamic nitrogen atmosphere. The exothermic reaction kinetics was studied by differential scanning calorimetry (DSC) in non-isothermal conditions. The Arrhenius parameters were estimated according to the Ozawa method. The calculated activation energy was 134.5 kJ mol -1 , the pre-exponential factor, A, was 2.04⋅10 10 min -1 and the reaction order for the global composite decomposition was estimated in 0.7 by the kinetic Shimadzu software based on the Ozawa method. The Kissinger method for obtaining the activation energy value was also used for comparison. These results are discussed here.
TG studies of a composite solid rocket propellant based on HTPB-binder
Journal of Thermal Analysis and Calorimetry, 2000
Thermal decomposition kinetics of solid rocket propellants based on hydroxyl-terminated polybutadiene-HTPB binder was studied by applying the Arrhenius and Flynn-Wall-Ozawa's methods. The thermal decomposition data of the propellant samples were analyzed by thermogravimetric analysis (TG/DTG) at different heating rates in the temperature range of 300-1200 K. TG curves showed that the thermal degradation occurred in three main stages regardless of the plasticizer (DOA) raw material, the partial HTPB/IPDI binder and the total ammonium perchlorate decompositions. The kinetic parameters E a (activation energy) and A (pre-exponential factor) and the compensation parameter (S p ) were determined. The apparent activation energies obtained from different methods showed a very good agreement.
Indian Journal of Chemical Technology
Hydroxyl terminated polybutadiene (HTPB)-ammonium perchlorate (AP) composite solid propellants (CSPs) have been prepared by incorporating five bis(ethylenediamine)metal perchlorate (BEMP) complexes like [M(en) 2 ](ClO 4) 2 (where, M = Mn, Fe, Co, Ni, Cu, Zn and en = ethylenediamine) as ballistic modifiers. The steady burning rate of the propellants was increased considerably by the additives, [Fe(en) 2 ](ClO 4) 2 being the most efficient one. The condensed phase thermolysis of unmodified and modified propellants was studied using simultaneous thermogravimetry (TG)-differential thermal analysis (DTA) in nitrogen atmosphere. Thermolysis of propellants is affected when these energetic additives are used as burning rate modifiers in small percentage (2% by wt.). Ignition delay (t id) measurements on propellants have been conducted to examine the effect of these additives under the condition of rapid heating. The role of these additives on thermal decomposition of oxidizer (AP) is also investigated using simultaneous TG-DTA in N 2. Also rapid thermolysis of pure AP as well as AP + additive mixtures was assessed by t id measurement technique. The complexes of Fe and Cu show considerable effect on both slow and rapid thermolysis of propellants and AP.
Zenodo (CERN European Organization for Nuclear Research), 2003
Effect of some bis(ethylenediamine)metal nitrate (BEMN) complexes, i.e. [M(enhi(N0 3 h (where, M = Cu, Co, Ni and Zn and en = ethylenediamine) during the t:ondensed phase thermolysis of hydroxyl-terminated polybutadiene (HTPB) and ammonium perchlorate (AP) composite solid propellants (CSPs) has been studied using TG and DTA. The results indicate that the thermolysis of propellants is affeded when these energetic complexes are used as burning rate modifiers in small percentage (2% by wt). Ignition delay (t;d) measurements on unmodified and modified propellants have been conducted to examine the effect of these additives during the rapid thermolysis of propellants. The response of the modified propellants to drop weight impact is determined to know the safety aspects. The effect of these additives on thermal decomposition of oxidizer (AP) is also investigated. Copper and cobalt complexes show considerable effect while nickel and zinc moderate effect on both propellants and AP decomposition.
Researches on Thermal Decomposition Kinetics of Composite Modified Double-base Propellants
Chinese Journal of Chemistry, 2011
The thermal decomposition kinetics of composite modified double-base (CMDB) propellants with a series of contents of hexogeon (RDX) was investigated by using parameters of T eo , T i , T p , T f , T b , T a , E, lg A and ∆H, which were obtained from using a CDR-4P differential scanning calorimeter (DSC) and Perkin-Elmer Pyris 1 thermogravimetric analyzer (TG) analyses with heating rates of 5, 10, 15 and 20 K/min. Reliable activation energy was calculated using Flynn-Wall-Ozawa method before analyzing the thermal decomposition mechanism. TG-DTG curves were treated with Malek method in order to obtain the reaction mechanisms. The obtained results show that the thermal decomposition mechanisms with the conversion from 0.2 to 0.4 was f(α)＝1/2α, and with the conversion from 0.5 to 0.7 was f(α)＝(1/4)(1-α) [-ln(1-α)] -3 .
Defence Technology, 2018
In the present investigation an effort has been made to understand the thermal decomposition and burn rate characteristics of AP as oxidizer and PVC and HTPB as fuel binder in composite solid propellant. The burning rate study has been carried out at ambient and different pressures of 2.068Mpa, 4.760Mpa, 6.895Mpa. The mechanism of thermal decomposition of each composition have also been determined by NETZSCH simultaneous thermal analyser, comprising differential scanning calorimeter (DSC) and thermo-gravimetric analyser (TGA). An effort has been made to study the burn rate and decomposition of fuel binder and oxidizer in presence of Fe 2 O 3 and also their overall impact on combustion of propellant.
Combustion and thermal decomposition characteristics of composite solid propellan
Thermochimica Acta, 1976
The role of thermal decomposition of the binder and the oxidiser in the thermal decomposition, ageing and combustion of composite soIid-propellants has been in&stigated_ The pre&nt study shows that the burning rate and'ageing of polystyrene and ammonium perchlorate propellant are related to the thermal decomposition of the propellant itself and ammonium perchlorate,
Journal of Research Updates in Polymer Science, 2015
The effects of two binders (PET and HTPB) on thermal decomposition characteristics of Ammonium Perchlorate were studied by TG-FTIR, DSC and SEM. When Hydroxyl-terminated polybutadiene (HTPB) mixes with AP, there is no obvious mutual effect in the process of heating, but it happen in the other way when Hydroxyl-terminated random copolyether (PET) mixes with AP. During the heating process of PET-AP mixture, the decomposition of PET occur in advance significantly, so that the porous structure of AP at the low-temperature decomposition stage becomes more significant, the total amount of heat released increases significantly, and the weight-loss ratio of AP about the two stages increases to about 2:1. During the thermal decomposition, the heat release and N2O gas production of PET-AP mixture is milder than the HTPB-AP, which is more conducive to the insensitive properties of propellant.