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1

Simulation of Stress Relaxation Behaviour of Composite Propellants with Varying Solid Loading Using the Generalized Maxwell Model

Bihari Bipin Kumar, Kumaraswamy Adepu, Jain Mukesh, Kurva Ramesh, Vipin Lisha

Central European Journal of Energetic Materials

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2023

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Vol. 20, no. 2

221--235

EN

Hydroxyl-terminated polybutadiene (HTPB) based composite propellants possess viscoelastic behaviour and hence time and temperature dependent mechanical properties. The mathematical analysis of viscoelastic behaviour of composite propellants becomes complex due to the non-linearity involved under various loading conditions. In the present study, a linear viscoelasticity assumption was considered to simulate stresses related to storage conditions. In this paper, a study of stress relaxation behaviour of composite propellants was carried out using the Generalized Maxwell model to obtain the material viscoelastic characteristics. The relaxation behaviour of composite propellants having solid loading varying from 85% to 89% were studied at different temperatures, from –27 to +32 °C, using a Dynamic Mechanical Analyser (DMA). The generated relaxation curves were curve fitted using MATLAB (R2022a) with the Generalized Maxwell model. The simulation demonstrated that a maximum of four elemental parameters of the Generalized Maxwell model are sufficient and can represent a best fit of the relaxation behaviour of the studied composite propellants. The equilibrium modulus was also evaluated at different temperatures, along with other material constants that are essential parameters for performing the structure integrity analysis of a solid propellant rocket motor. It was observed that the equilibrium modulus decreases with an increase in temperature, but increases with an increase in solid loading in the propellant composition formulations.

2

Composite Propellant Formulation of Poly (16-, 32- and 64-) Azido Dendritic Esters as Energetic Plasticizer and Evaluation of Properties

Yamajala Kanaka Durga Bhaskar, Singh Hema, Kurva Ramesh, Maurya Mehilal, Banerjee Shaibal

Central European Journal of Energetic Materials

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2020

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Vol. 17, no. 4

506--522

EN

16-, 32- and 64-Polyazido hyperbranched dendrimers were synthesized from hydroxy terminated dendritic ester by following two steps namely, tosylation and azidation. The poly azido dendrimers were incorporated in composite propellant formulations as an energetic plasticizer. The physical, thermal sensitivity and ballistic properties of these composite propellants such as burning rate, Cal-val, density, ignition/decomposition temperature (AET), DSC-TGA, mechanical properties, impact and friction sensitivity were evaluated experimentally while the specific impulse (Isp) and characteristic velocity (C*) were obtained theoretically. A significant enhancement in heat release was noted in the propellant formulation having 16-azido dendritic ester as an energetic plasticizer compared to 32- and 64-azido dendritic esters and a reference composition.

3

Influence of Dispersion Methods on the Mechanical, Thermal and Rheological Properties of HTPB-based Nanocomposites: Possible Binders for Composite Propellants

Ghosh Kavita, Kumar Arvind, Banerjee Shaibal, Patro Uma Sankar, Gupta Manoj

Central European Journal of Energetic Materials

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2019

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Vol. 16, no. 2

281--298

EN

The present study reports on the methods of preparation for HTPB-clay nanocomposites and their mechanical, thermal and rheological properties for their functional utility as an improved binder system for composite propellants. HTPB-clay nanocomposites were prepared by dispersing organoclay Cloisite 30B (1-3 wt.%) in the polymer matrix by magnetic stirring and high shear mixing. Critical parameters like time, temperature and RPM were optimized. These nanocomposites were cured with toluene diisocyanate in the presence of the cure catalyst DBTDL. The dispersion of the nanoclay was evaluated by using small angle X-ray scattering (SAXS) and energy dispersive X-ray (EDX) spectroscopy. EDX suggested homogeneous distribution while SAXS revealed partial exfoliation of the clay particles in the polymer matrix. Superior dispersion of the nanoclay was obtained by high shear mixing. The tensile properties of the nanocomposites prepared by high shear mixing showed 10-20% more strength and elastic modulus. The nanocomposites showed thermal stability higher than the pristine HTPB. Swelling behavior revealed increased cross linking, and the rheological behavior exhibited higher viscosity of the nanocomposites. In addition, the clay amount was increased up to 10 wt.% and its effect on the mechanical, thermal and swelling behavior was observed. Theoretical performance predictions of composite propellants with nanocomposites revealed their possible functional utility.

4

Evaluation of Strontium Ferrite (SrFe12O19) in Ammonium Perchlorate-based Composite Propellant Formulations

Jain Sunil, Kshirsagar Dhirendra R., Khire Vrushali H., Kandasubramanian Balasubramanian

Central European Journal of Energetic Materials

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2019

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Vol. 16, no. 1

105--121

EN

In the present work, various propellant compositions were prepared by incorporating strontium ferrite (SrFe12O19) in an ammonium perchlorate (AP), aluminium powder and hydroxyl-terminated polybutadiene (HTPB) based standard composite propellant. The compositions were then studied by assessing the effect of the SrFe12O19 content on the propellant slurry viscosity, and the mechanical and ballistic properties. The results showed that as the percentage of SrFe12O19 in the propellant was increased, the end of mix (EOM) slurry viscosity, tensile strength and E-modulus increased, while the elongation decreased. The ballistic properties data revealed that the burning rate of the propellant composition containing 1.0% SrFe12O19 was enhanced by around 15% (at 6.86 MPa) compared to the standard composition burning rate.

5

Studies on the Effect of Nano-MnO2 in HTPB-based Composite Propellant Formulations

Kshirsagar D. R., Jain S., Bhandarkar S., Vemuri M., Mehilal

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 3

589--604

EN

Various propellant compositions were prepared incorporating fully characterized nano-sized manganese dioxide, from 0.25 wt.% to 1.0 wt.%, in HTPB/AP/Al-based composite propellant formulations having 86 wt.% of solid loading, and its effects on the viscosity build-up, thermal, mechanical and ballistic properties were studied. The findings revealed that on increasing the percentage of nano-MnO2 in the composition, there was an increase in the end of mix viscosity, the modulus and tensile strength, while the elongation decreased accordingly. The data on the thermal properties revealed a reduction in the decomposition temperature of ammonium perchlorate (AP) as well as of the formulations based on it. The data on the ballistic properties revealed that there is an enhancement in the burning rate from 6.11 mm/s (reference composition) to 7.54 mm/s at 6.86 MPa (a 23% enhancement in the burning rate) and an increase in the pressure exponent from 0.35 (reference composition) to 0.42 with 1.0 wt.% nano-MnO2.

6

Experimental Approaches to Develop a High Thrust Ratio in a Single Chamber Dual Thrust Motor Using a Composite Propellant Formulation Based on HTPB/AP/Al

Kurva R., Ukey S., Modgi M., Mehilal

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 4

917--932

EN

A high thrust ratio in a single chamber dual thrust motor is required to reach a peak velocity very quickly. To achieve a high thrust ratio in a single chamber dual thrust motor, a composite propellant grain, which acts both as booster and sustainer, based on HTPB/AP/Al (84% solid loading) with low aluminum content and having a burning rate of 25±0.5 mm/s at 7 MPa, was successfully developed. This was studied for viscosity build-up, mechanical and ballistic properties, followed by casting and curing as a single type propellant grain. The high burning surface area was created by making grooves of 3 mm width and 60 mm depth over the surface of the nozzle side of the grain while casting and a prototype, thus obtained, was static tested. The data revealed that a grain with one groove demonstrated a thrust ratio of 8, while two grooves, realized a thrust ratio of 30. The experimental thrust ratio values achieved are also in agreement with the predicted values of the thrust ratio of the same composition.

7

Optimal design of a composite propellant formulation using response surface methodology

Hamed J. O., Ogunleye O. O., Osheku C. A.

Advances in Materials Science

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2017

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Vol. 17, nr 1(51)

44--57

EN

There is a continuous demand for high performance composite propellant formulations to meet mission requirements. The performance of composite propellant formulations can be enhanced by optimizing propellant formulation. However, the main objective of this study is to formulate a composition for composite propellant by optimizing the specific impulse which is the measure of propellant performance. A central composite design (ccd) consisting five ingredients (ammonium nitrate, powdered aluminum, polyester resin, ammonium dichromate and powdered charcoal) at five levels was used to formulate optimum propellant formulation from composite materials of ammonium nitrate based propellant verified for propellant characteristics using propellant performance evaluation programme (propep 3). The responses evaluated are specific impulse, characteristic velocity, density, temperature and molecular weight. Response surface methodology was used to analyze the results of the ccd of the composite formulations. The optimum values for specific impulse, characteristic velocity, density, temperature and molecular weight of the mixture from the surface plot are 212.178 s, 1335.81 m/s, 1640.6 k g/m3, 1968.73 k and 21.7722 g/mol respectively. The optimum predicted specific impulse was 212.178 s at composite composition of 73.61% ammonium nitrate, 4.36% powdered aluminum, 14.39% polyester resin, 5.10% ammonium dichromate and 2.54% powdered charcoal. The propellant optimum composition validated with propep 3 are in good agreement with each other in their accompany propellant characteristics. Therefore, the optimal propellant formulation enhanced the performance of solid propellants.

8

Evaluation of Potassium Perchlorate as a Burning Rate Modifier in Composite Propellant Formulations

Jain S., Mehilal D., Singh P. P., Bhattacharya B.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 1

231--245

EN

The burning rate of a solid composite propellant is one of its most important ballistic properties. To achieve a specified burning rate, transition metal oxides are used as burning rate modifiers. However, addition of transition metal oxides creates inertness in the composition. To avoid such inertness, an attempt has been made to incorporate potassium perchlorate (KP) as a burning rate modifier by partially replacing ammonium perchlorate (AP), up to the 10% level, and the composition was then studied in detail for its mechanical, thermal and ballistic properties. The data revealed that no change occurred in the case of the mechanical properties, however, the thermal stability decreased as the KP content was increased. The burning rate data revealed that on incorporation of 10% KP, there was an enhancement in the burning rate of up to 35% in comparison to the original composite propellant formulation, but beyond this no enhancement in burning rate was observed, indicating that the optimum content for KP in the composition had been reached.

9

Opracowanie technologii i badania balistyczne zespołu napędowego do 122 mm pocisku rakietowego o wydłużonym zasięgu

Florczak B., Cholewiak A., Białek M.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2015

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Vol. 6, Nr 1 (19)

103-118

PL

W artykule przedstawiono wyniki badań balistycznych silnika rakietowego demonstratora 122 mm pocisku rakietowego o wydłużonym zasięgu z heterogenicznym stałym paliwem rakietowym. Opracowana technologia wytwarzania materiału pędnego stałego może być wdrożona w zakładach przemysłu obronnego i wykorzystana do produkcji silników rakietowych różnego przeznaczenia.

EN

The paper presents the results of ballistic studies on the demonstrator missile 122 mm rocket motor of an extended range with the heterogeneous solid propellant. The technology for producing the solid propellant can be deployed in the defense industry plants and used for the production of rocket motors for various purposes.

10

Towards New Directions in Oxidizers/Energetic Fillers for Composite Propellants: an Overview

Dey A., Sikder A. K., Talawar M. B., Chottopadhyay S.

Central European Journal of Energetic Materials

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2015

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Vol. 12, no. 2

377--399

EN

There is continued interest in the development of safe and reliable composite propellant formulations using modern energetic ingredients such as energetic oxidizers/energetic ingredients, energetic binders, and energetic ballistic modifiers. There are continued efforts by energetic materials researchers, scientists, technologists and engineers to design composite propellant formulations with better ballistic properties than conventional formulations. The efforts in many research and development (R & D) laboratories all over the world are aimed at utilizing modern oxidizers/ energetic fillers for the development of composite propellant formulations for both space and defence applications. Composite propellants are considered to be the major source of chemical energy for rockets and missiles. Energetic oxidizers/fillers play vital roles in the preparation or manufacture of composite propellant formulations. Various energetic oxidizers/fillers have been developed during the last five decades to address environmental safety, high energy and processing conditions. In this article, the authors have reviewed the characteristic properties of the energetic oxidizers/fillers used in the preparation of composite propellants. The characteristic properties of the energetic ingredients play an important role in the preparation of composite propellant formulations with the desired mechanical properties. The advantages and disadvantages of various energetic oxidizers/ingredients for specific and potential propellant applications are also highlighted throughout the course of this review article. The future direction in composite propellant formulations calls for the development of green propellant formulations. Efforts will continue to seek alternative and more energetic oxidizers/fillers in comparison to conventional oxidizers. There is an urgent need to replace conventional oxidizers such as ammonium perchlorate with eco-friendly ingredients.

11

Influence of Polyglycidyl-type Bonding Agents on the Viscoelastic Properties of a Carboxyl-terminated Poly(butadiene-co-acrylonitrilе)-based Composite Rocket Propellant

Brzić S., Dimić M., Jelisavac L., Djonlagić J., Ušćumlić G., Bogdanov J.

Central European Journal of Energetic Materials

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2015

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Vol. 12, no. 2

307--321

EN

In the present study, functionally substituted bonding agents (triglycidyl isocyanurate and diglycidyl dimethylhydantoin) were incorporated into a composite propellant formulation based on carboxyl-terminated poly(butadiene-co-acrylonitrilе) and ammonium perchlorate. Bonding agents are an important component of a composite propellant, making up to 0.5 wt.% of the formulation. They affect processing, mechanical properties, ballistics, ageing and the characteristics of insensitive munition (IM) propellants. All of the testing has been done using an unmetallized propellant formulation (80 wt.% bimodal ammonium perchlorate and 20 wt.% binder). The focus has been on the mechanical properties of the propellant, as influenced by the presence of these bonding agents. Mechanical uniaxial tensile tests were accompanied by a dynamic mechanical analysis (DMA) over a wide range of temperatures. The storage modulus, loss modulus, loss factor and glass transition temperature for each propellant sample have been evaluated. The network characteristics, such as sol-gel content and crosslink density have been calculated and successfully correlated with the mechanical properties. The dynamic mechanical studies showed that the content of the bonding agent did not influence the glass transition temperature; however, the loss factor was shown to be a function of the crosslink density.

12

Badanie wpływu wodorku glinu na skład chemiczny produktów i ciepło spalania złożonych paliw rakietowych

Papliński A., Zygmunt B.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2014

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Vol. 5, Nr 1 (15)

41-50

PL

W pracy przedstawione zostały wyniki analizy składu chemicznego oraz parametrów termodynamicznych produktów spalania złożonych paliw rakietowych zawierających wodorek glinu AlH3. Rozpatrywane są paliwa oparte na chloranie(VII) amonu (NH4ClO4), w których jako lepiszcze stosowany jest kauczuk typu HTPB. Jako składniki energetyczne paliwa rozpatrywane są Al i AlH3. Przedmiotem pracy jest zbadanie, w jaki sposób zastąpienie Al przez AlH3 wpływa na skład chemiczny i właściwości produktów spalania. Skład chemiczny i parametry termodynamiczne produktów spalania określono za pomocą programu obliczeniowego MWEQ. Przy zachowaniu tego samego udziału masowego, wprowadzenie AlH3 zamiast Al prowadzi do obniżenia temperatury produktów przemiany, wzrasta ilość moli produktów w stanie gazowym, odniesiona do jednostki masy paliwa. Uzyskane wyniki potwierdzają przydatność wodorku glinu AlH3 jako perspektywicznego składnika energetycznego paliw rakietowych.

EN

The influence upon chemical composition and heat of combustion of composite propellant that occurs as a result of substitution of aluminium by its hydride AlH3 is investigated. Propellants based on ammonium chlorate(VII) (NH4ClO4) modified by standard HTPB binder are considered. Chemical composition and thermodynamic parameters of combustion products are evaluated by MWEQ computer program supplied with large species database. The particular attention is paid to proper choose of thermodynamic data describing temperature dependence of heat capacity, enthalpy and entropy of chemical compounds belonging to Al-Cl-O-H group. The alteration of chemical composition and temperature of combustion products that is followed by replacement of Al by AlH3 is illustrated in a quantitative mode. The prospective applicability of AlH3 as an energetic component of composites propellants is confirmed.

13

Biuret: a Potential Burning Rate Suppressant in Ammonium Chlorate(VII) Based Composite Propellants

Dey A., Ghorpade V. G., Kumar A., Gupta M.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 1

3--13

EN

Several composite propellant compositions containing various concentrations of biuret, a new burning rate suppressant, were formulated and studied to optimize the concentration of biuret in the composite propellant. Biuret was used here for the first time in a composite propellant as a burning rate suppressant. The theoretical properties of the compositions containing different concentrations of biuret were computed by using the NASA CEC-71 programme and the burning rate performances were evaluated. In addition, the sensitivity, thermal and mechanical properties of the compositions were also evaluated. The composition containing ammonium chlorate(VII) (AP) 65%, Al 15%, binder 20% and biuret 0-6% over the batch were prepared. The composition containing 6% biuret over the batch was insensitive to friction and impact. As the amount of biuret was increased, the energy, burning rate and sensitivity decreased, whilst the auto ignition temperature increased. The formulation containing 4% biuret over the batch was found to be the optimum with respect to energy, burning rate, pressure index, and sensitivity.

14

Synteza i zastosowanie wodorku glinu jako składnika paliw rakietowych

Zygmunt B., Pietrzykowski A., Jurkowski J., Lipiński M., Dębski A.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2013

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Vol. 4, Nr 1 (11)

87-96

PL

W artykule przedstawiono wyniki pracy dotyczące opracowania mokrej syntezy (bezciśnieniowej) wodorku glinu. Związek ten jest interesujący dla techniki magazynowania wodoru, ponieważ zawiera 10% masowych łatwo wydzielanego wodoru. Jako dodatek energetyczny do heterogenicznych paliw rakietowych powoduje wzrost impulsu właściwego paliwa do 300 sekund. Opisano metodę otrzymywania wodorku glinu i sposób stabilizacji produktu. Wykonano próbki paliwa rakietowego z dodatkiem 10% wodorku glinu i zmierzono wybrane właściwości balistyczne – ciepło spalania i prędkość palenia.

EN

Results of the research focusing on the wet synthesis of aluminum hydride (AlH3) were summarized. The compound is the object of interest in hydrogen storage due to its high concentration of hydrogen (10,1% by mass). Composite propellants containing 20-25% of AlH3 can achieve high specific impulse, up to 300 seconds. In the paper the synthesis of the compound is described and the key stabilization method is underlined. The scanning electron microscopy picture of the crystals were shown. The stabilized form of the AlH3 were used to prepare samples of composite propellants and their basic parameters were measured. AlH3 as an ingredient of composite propellants significantly increases the heat of combustion and the rate of burning.

15

Studies on High Burning Rate Composite Propellant Formulations using TATB as Pressure Index Suppressant

Mehilal, Jawalkar S., Kurva R., Sundaramoorthy N., Dombe G., Singh P. P., Bhattacharya B.

Central European Journal of Energetic Materials

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2012

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Vol. 9, nr 3

237-249

EN

High burning rate propellant compositions are generally used in gas generators to eject missile from canister. Because of high burning rate, pressure index of the composition increases during burning. To reduce the pressure index, a high burning rate composite propellant formulations (~20 mm/s) based on AP/HTPB/Al have been prepared by incorporating TATB and studied in detail for viscosity build-up, thermal and mechanical properties, sensitivity as well as burning rate and pressure index (n). The data indicate that there is a decrease in end of mix viscosity on increasing the percentage of TATB. The same trend was also observed with mechanical properties while significant improvement in overall thermal stability was clearly observed. The sensitivity data indicate that impact and friction values show decreasing trend infer better safe to handle. The burn rate data reveal that on addition of TATB from 0.5 to 2% decrease in burning rate was not observed while on addition of further TATB up to 5% and beyond this significant decrease in burning rate was observed. The data on pressure index (n) also reveal that TATB is very effective in reducing the 'n' value up to 2% and beyond this 'n' value increases close to standard composition. The data on 'n' value reveal that it reduces from 0.47 to that of standard composition to 0.36 for the compositions containing TATB up to 2.0% in the pressure range of 60-90 kg/cm2.

16

Development of a Composite Propellant Formulation with a High Performance Index Using a Pressure Casting Technique

Ramesh K., Jawalkar S. N., Sachdeva S., Bhattacharya B.

Central European Journal of Energetic Materials

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2012

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Vol. 9, nr 1

49-58

EN

There is a continuous demand for high performance composite propellant formulations to meet future requirements. The performance of composite propellant formulations can be enhanced by the addition of energetic oxidizers, like ADN/HNF as well as an energetic binder & a plasticizer. However, on incorporation of energetic ingredients, the composition becomes sensitive, and thus processing, handling and transportation pose a greater threat. Therefore, a moderately high burn rate composition having a burn rate ~ 13-14 mmźs -1 at 7000 kPa was tailored by increasing the solid loading of the propellant from 85.15% to 87.27% with the help of ammonium perchlorate and process aids without affecting the burn rate and mechanical properties. The tailored composition was studied for different properties such as end of mix viscosity, density, mechanical & ballistic properties. The evaluated data reveal that the end of mix viscosity of the tailored composition is higher than the base composition, i.e., 672 Paźs and 2340 Paźs at the same temperature; however, this viscosity was castable using a pressure casting technique. The properties of the cured propellant reveal that there is an enhancement of density from 1.74 gźcm -3 to 1.79 gźcm -3 with no other changes in mechanical properties. The performance index of the tailored composition has been increased from 416 to 437, well supported by results of ballistic evaluation motors of 2 kg.