The advent and use of advanced eco-friendly energetic materials to obtain higher and higher energy and reduced vulnerability, improved mechanical properties along with reduced signature profile and extended useful life has assumed very high importance these days. Use of new powerful and green oxidizers like ADN, HNF and ammonium ozonide along with energetic binders like GAP, BAMO and BAMO-THF copolymer can boost specific impulse (Is) to more than 320 s. Inclusion of energetic plasticizers like tetra azido malonate and tetra azido glutarate can enhance energy further. Likewise, inclusion of nitrogen-rich compounds like nitro guanidinium azides, N8, N10, etc., can boost energy further on higher side. Addition of nano metal powders and nano metal hydrides is likely to enhance burn rates significantly. Thus, there is need to generate reliable exhaustive technical data on the utility of new eco-friendly materials reported recently to obtain unthinkable boost in energy and burn rates.

Propellants contain considerable chemical energy that can be used in rocket propulsion. Bringing together information on both the theoretical and practical aspects of solid rocket propellants for the first time, this book will find a unique place on the readers' shelf providing the overall picture of solid rocket propulsion technology. Aimed at students, engineers and researchers in the area, the authors have applied their wealth of knowledge regarding formulation, processing and evaluation to provide an up to date and clear text on the subject.

A modular approach towards a series of novel di azido, tetra azido and hexa azido esters is introduced here.

The study of a cyclotrimethylene trinitramine-based low vulnerable ammunition (LOVA) propellant having cellulose acetate (CA) and nitrocellulose (NC) combinations as binders is described herein. Two propellant compositions (1 and 2) were prepared by replacing the non energetic plasticizer triacetin (TA) with the novel tetraazido ester plasticizers tetraazido malonate and tetraazido glutarate, respectively, and their ballistic, mechanical, and thermal properties were studied. Both compositions 1 and 2 showed thermal stability up to 200 degrees C with a heat release of 1752.81 and 1774.34Jg(-1), respectively. Both compositions have high impact insensitivity (h(50): 39cm), friction insensitivity up to 36kg, and an ignition temperature greater than 250 degrees C. The flame temperatures of 1 and 2 are 3164 and 3243K with linear burn rate coefficients of 0.117 and 0.122cms(-1) MPa-1, respectively. Similar percentage elongations at three different temperatures (-20 degrees C, +27 degrees C, and +55 degrees C) conditions were recorded for both compositions.

This paper describes the synthesis and characterization of two novel tetra-azido energetic plasticizers from readily available commercial sources possessing good thermal stability. Two new energetic azido esters named bis(1,3-diazido prop-2-yl)malonate (1) and bis(1,3-diazido prop-2-yl)glutarate (2) have been synthesized and characterized by IR, H-1 NMR, C-13 NMR, HRMS, thermal analysis, and compatibility tests. Both azido esters (1 and 2) show good thermal stability with decomposition temperatures of 233.5 degrees C and 232.6 degrees C. Their densities are measured to be 1.25 g/cm(3) and 1.27 g/cm(3), respectively. Glass transition temperature (T-g) of both compounds 1 and 2 is -69 degrees C and -68 degrees C and after addition with binder shows reduction in T-g of polymer-plasticizer blends as compared to T-g of polymer only with single decomposition temperature values which indicate the presence of single phase homogeneous system. Thermal decomposition kinetics of both compounds was determined by DSC, using non-isothermal Kissinger and Friedman differential isoconversional method. Density functional theory calculations on compounds 1 and 2 predict positive heats of formations. (C) 2013 Elsevier B.V. All rights reserved.

The burning rate pressure relationship is one of the important criteria in the selection of the propellant for particular applications. The pressure exponent (?) plays a significant role in the internal ballistics of rocket motors. Nitramines are known to produce lower burning rates and higher pressure exponent (?) values. Studies on the burning rate and combustion behavior of advanced high-energy NG/PE-PCP/AP/Al- and NG/PE-PCP/HMX/AP/Al-based solid rocket propellants processed by a conventional slurry cast route were carried out. The objective of present study was to understand the effectiveness of various ballistic modifiers viz. iron oxide, copper chromite, lead/copper oxides, and lead salts in combination with carbon black as a catalyst on the burning rate and pressure exponent of these high-energy propellants. A 79?% increase in the burning rates and almost no effect in pressure exponent values of propellant compositions without nitramine were observed. However, in case of nitramine-based propellants as compared to propellant compositions without nitramines, slight increases of the burning rates were observed. By incorporation of ballistic modifiers, the pressure exponents can be lowered. The changes in the calorimetric values of the formulations by addition of the catalysts were also studied.

Nitramines are known to produce lower burning rates and higher pressure exponent (?) values. Studies on the burning rate and combustion behavior of advanced high-energy NG/PE-PCP/HMX/AP/Al based solid propellant processed by slurry cast route were carried out using varying percentages of HMX and AP. It was observed that propellant compositions containing only AP and Al loaded (total solids 75?%) in NG plasticized PE-PCP binder produce comparatively lower pressure exponent (?) values similar to AP-Al filled HTPB based composite propellants. However, energetic propellants containing high level of nitramine (40-60?%) produce high pressure exponent (0.80.9) values in the same pressure range. Incorporation of fine particle size AP (ca. 6 mu m) and change in its concentration in the propellant composition reduces ? value marginally and influences the burning rate. However, such compositions have higher friction sensitivity.

The mechanical properties of solid rocket propellants play a vital role in the efficient functioning of rocket motors over a wide range of temperatures. A propellant grain must maintain its structural integrity during storage, handling, and various dynamic loads, such as acceleration during flight. The tensile strength, percentage elongation and elastic modulus are the inherent properties of the propellant and are more significant during the development of solid propellant for a particular mission. The polymeric binder largely determines the mechanical properties of the propellant. In this study, the mechanical properties of the cured prepolymer, cured nitroglycerin (NG) plasticized pentaerythritol-polycaprolactone prepolymer (PE-PCP) binder, and propellants have been evaluated at different temperatures. The glass transition temperatures (T-g) of these samples were also evaluated to study the effect of plasticization, isocyanate used as the curing agent, and the NCO: OH ratio. Propellant formulations for case-bonded applications having high plasticizer (Pl) to polymer (Po) ratio (Pl/Po > 2) containing solid energetic materials as ingredients were evaluated for their structural integrity by determining the mechanical properties at ambient (+ 27(circle)C), cold (-40(circle)C), and hot (+ 55(circle)C) conditions. It has been observed that the tensile strength, percent elongation, and elastic modulus increase at the cold condition (-40(circle)C) compared to the ambient and hot conditions. This distinctive characteristic of the propellant is due to the presence of highly plasticized prepolymer in the formulation.

Energetic plasticizers have been used in the propellant industry for improving mechanical properties of propellant formulations and to boost energy. In modern energetic propellant composition, conventional plasticizers are being gradually replaced by energetic plasticizers having nitro, nitroamino, azido and other energetic groups or combination of energetic groups in the same molecule. The present article covers the recent advances in the field of energetic plasticizers with special reference to their applications in gun and rocket propellants. The paper also covers future scope for R&D work in this area.

New energetic salts may be synthesized via the quarternization of azido or nitro derivatives of 1,2,4-triazole, and substituted derivatives of tetrazole with nitric acid or perchloric acid or iodomethane followed by metathesis reaction with AgNO3 or AgClO4 have been suggested in the literature for synthesis of new energetic ionic salts. The present review focuses briefly on the synthesis aspects and some of the physico-chemical properties of energetic materials of the class have been investigated. The structures of prospective energetic ionic salts include (a) 1-(2-azidoethyl)-1,2,4-triazolium-5-nitrotetrazolate, (b) 1-(2-azidoethyl)-3-azido-1,2,4-triazolium 5-nitrotetrazolate, (c) 1-(2-azidoethyl)-4-amino-1,2,4-triazolium perchlorate, 1-(2-azidoethyl)-1,2,4-triazole and so on. These compounds may find a wide spectrum of futuristic applications in the area of energetic materials. The salts exhibit good thermal stabilities, low vapour pressure, high heat of formation and high densities. Constant volume combustion energies may be determined experimentally using oxygen bomb calorimeter, DSC, 1H and 13C NMR. The standard molar enthalpies of formation will be derived from designed Hess thermochemical cycles.

The advent of new energetic materials such as ADN, HNF, NTO, CL-20, etc., the availability of energetic binders such as GAP, BAMO, AMMO etc., energetic plasticizers such as butyl NENA, DANPE, etc. has opened a new era in the development of advanced solid propellants, capable of delivering a very high energy (Isp similar or equal to 300 s). The emergence of nano-energetic materials is likely to change the scene of advanced propellants drastically. This paper reports the results of research and development carried out on propellants based on HNF, CL-20, and metallic powders, like Zr and Ti, with both conventional and energetic binders, and energetic plasticizers. Advanced solid propellant compositions containing 60% RDX along with GAP as the energetic binder and TMETN as the energetic plasticizer produced burn rate of around 15 mm/s, whereas a composition containing CL-20 and GAP produced burn rates of 20 mm/s. CL-20 has an edge over RDX/HMX, as a potential oxidizer or high energy additive. The combination of HNF with GAP and the BAMO/THF copolymer as a binder with metal hydrides appears to be highly promising when taking into account energy considerations. The of 40% HNF in a NC-NG matrix with GAP as the energetic plasticizer produced a burn rate of 36mm/s at 9 MPa with a pressure index of 0.70 and is capable of producing Isp of 270 s. The use of 50-60% Zr powder-based fuel rich propellants produced stable combustion in a primary motor. The replacement of conventional plasticizers with energetic plasticizers raised the burn rate by 2-3 fold for Ti-and Ni-based fuel rich propellants.

To overcome the limitations of conventional single base, double base and triple base propellants, advanced low vulnerability ammunition (LOVA) propellants are being developed based on nitramines (RDX/HMX), energetic and non-energetic binders, and energetic plasticizers. LOVA propellants constitute an important branch of insensitive munitions (IM). In the present study, LOVA propellants, based on cellulose acetate (CA) and hydroxy terminated poly butadiene (HTPB) and their mixture as binders, with RDX and nitrocellulose (NC) as fillers and low molecular weight glycidyl azide polymer (GAP) (Mw 400-600) as energetic plasticizer were evaluated. The results obtained indicate that by using 70% RDX, 15% NC, 9% binders (CA/HTPB), and 6% GAP as plasticizer, the figure of insensitivity was increased to the 34-40 level. CA produced a figure of insensitivity (F of I) of 40 with a height of 50% explosion of 34 cm. These propellants can produce force constant in the range of 11001150 J/g with linear burn rate coefficient of 0.3 cm/s/MPa. All the propellants studied are friction insensitive up to 36 kg weight. Their compressive strength is around 200 kg/cm(2) with a compression of 5-8%. By including GAP as a plasticizer, a force constant on the order of 1200 J/g was obtained and the linear burn rate coefficient was reduced to a 0.13 cm/s/MPa level with a pressure index of 0.97. An increase in concentration of RDX to 75% at the cost of NC content (10%) led to a force constant increase to 1200 J/g. F of I was around 36 without any change in friction insensitivity. Likewise, 80% RDX, 5% NC with CA and HTPB as binders with 6% GAP as energetic plasticizer produced a force constant of 1340 J/g with a linear burning rate coefficient of 0.11 cm/s/MPa. A height of 50% explosion was in the range of 27-28 cm with an F of I at 33. Friction insensitivity was up to 36 kg.

2,3-dimethyl-2,3-dinitrobutane (DMNB) has been internationally accepted as an additive for the purpose of marking, as it has desired vapour pressure for reliable detection. It is reported to be compatible with known explosive formulations and has a good shelf life. Explosive compositions with DMNB as marking agent can be detected in the temperature range -20 degrees C to + 50 degrees C. This paper describes modelling for quantifying activation energy for depletion of DMNB in the marked explosives, period for definite detection of the marked explosives and optimum initial concentration needed for the detection of DMNB content in the marked plastic explosives.

Boron-potassium nitrate (B-KNO3)-based compositions have been used as an effective igniter system for solid rocket propellants. A systematic study was undertaken to generate exhaustive data on B-KNO3 (25:65)-based ignition systems with cellulosic binders, viz., nitrocellulose, ethyl cellulose and plasticised ethyl cellulose. In addition, detailed investigations were carried out with PEC as binder by varying its concentration from 2-10 per cent in the same system. The experimental compositions (B-KNO3: binder) were evaluated by closed-vessel firing, thermal analysis, sensitivity, mechanical properties and cal-val determination. The binders significantly influenced the sensitivity and combustion behaviour of B-KNO3 compositions. The composition with nitrocellulose as binder produced high flame temperature and cal-val as compared to ethyl cellulose and plasticised ethyl cellulose-based compositions. The data indicated that the calculated flame temperature for all compositions was in the range 2716 K to 2957 K. As the plasticised ethyl cellulose content increased from 2 per cent to 10 per cent, the maximum pressure increased with decrease in heat of combustion.

Mercuric-5-nitrotetrazole (MNT) was synthesized on using a reported method. The product having bulk density of 1.5 g/cm3, was obtained during this work using mercuric nitrate doped with additives such as cephol/dextrin in the process. Synthesized MNT was characterized by metal content analysis, IR and ESCA. The DTA profile indicated the thermal stability of MNT up to 200 degrees C. It revealed its higher thermally sensitive [thermal sensitive figure (S) approximately 0.8] in comparison to that of service lead azide (SLA) [S approximately 0.4]. Percussion sensitivity data also showed higher sensitivity of MNT. However, it was found less friction sensitive than SLA. The chemical stability of MNT in a carbon dioxide environment was evaluated in comparison to SLA by determining mercury (gravimetrically) and lead azide (volumetrically) contents respectively. Results obtained indicated that no discernable changes occurred in MNT, even after storage for 90 days while in case of SLA, drastic change in lead azide content was observed. IR spectra of MNT sample stored in a closed aluminum dish for 5-10 years could be superimposed on that of the freshly prepared MNT sample. The performance of MNT filled detonator no. 27 assessed in terms of extent of damage on a witness plate was found equivalent to that of the standard ASA (azide, styphynate and aluminium) composition filled detonator.

The paper describes the development of aluminised plastic-bonded explosives (PBXs) based on aluminium and nitramine explosives using hydroxy-terminated polybutadiene as polymer matrix. The PBXs were processed as per standard procedures. Compositions with different formulations were prepared by varying the percentages of aluminium and RDX and their explosive properties, including velocity of detonation (VOD), peak overpressure, duration, impulse and sensitivity to different types of stimuli, were studied. The experimental and theoretical values of the VOD have been compared. It is observed that about 15 per cent aluminium content in the aluminised PBXs shows the optimum VOD.