Observation of Change in Colour of Combustible Cartridge Cases on Ageing-A Qualitative Tool

The stability of combustible cartridge cases (CCCs) which are extensively used in the high calibre tank gun ammunition is one of the major requirements for their safe handling and storage. The results of stability tests by heating of CCC samples at elevated temperatures and observations for change in colour of the CCC samples have been discussed. It has been observed that there are drastic changes in the colour of the CCC samples. The original pale yellow colour of the uncoated internal surface was changed to dark green. Similarly, original yellowish-brown colour of external surface coated with shellac varnish was changed to dark greenish-brown

Nitramine-Based High Energy Propellant Compositions for Tank Guns

Six different RDX-based gun propellant compositions have been formulated and studied to select the most suitable composition for tank gun ammunition in terms of higher force constant at relatively lower flame temperature (T). Ballistic'performance of the compositions was evaluated on the basis of closed vessel test. JIea(energy was determined using a bomb calorimeter. Sensitivity, thermal characteristics, stability and mechanical properties of the compositions were studied for assessing their suitabilitY for application. The composition containing 65 per cent RDX and 28 per cent nitrocellulose was found to provide higher level of force constant at relatively lower T f ' reasonably good burning rate characteristics and mechanical properties

Influence of Cellulosic Binders on Sensitivity and Combustion Behaviour of B-KNO3 Ignition System

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

Influence of lead Inorganic Compounds on Combustion Rate of Double Base Rocket Propellants

The influence of lead nitrate, red lead, lead chromate, lead floride and lead carbonate on the combustion behaviour of double base propellants in the pressure range-35-140kg/cm /sup 2/ was studied. While all these compounds increased burning rates in lower pressure range (35-60 kg/cm/sup 2/) and higher pressure range (120-140 kg/cm/sup 2/), only lead chromate and lead fluoride were effective in the intermediate pressure range of 60-105 kg/cm/sup 2/. None of these compounds were effective as platonizer, except lead fluoride, which lowered n value to 0.34 in the lower pressure range. Addition of carbon black along with lead compounds raised burning rates further and reduced n values significantly in the higher pressure regins. A probable mechanism on the role of lead compounds studied has been suggested based on burning rate and DTA results

Cross-Linked Slurry Cast Composite Modified Double Base Propellants : Mechanical Properties

Cross-linking of NC by TDI in slurry cast CMDB propellant enhanced TS by about 100 per cent. Coated AP with resorcinol, phloroglucinol, hexanetriol or silicone oil etc. along with cross-linking of NC raised TS from 18 - 30 kg/cm2. Inclusion of phloroglucinol and silicone oil gave increased burning rates. The probable mechanism of action of cross-linking and improvement of mechanical properties by coating of AP has been discussed

Synthesis and Characterisation of Poly (aminotrinitrophenylene)

Poly(amipotrinitrophenylene) (PATNP), a thermally-stable explosive has been synthesisied by ring amination of polynitropolyphenylene (PNP) using hydroxylamine hydrochloride in dimethyl formamide in the presence of alcoholic KOH. The compound has been characterised by infrared and differential thermal analysis (DTA), which showed an exothermic peak in the range 450-560 °C. Impact and friction sensitivities of PATNP were found to be less than those of PNP. Calorimetric value of the new compound was 3284 J/g

Metallised Fuel rich Propellants for Solid Rocket Ramjet: A Review

This paper reviews the research work carried out in the field of metallised fuel-rich propellants (FRP). Limitations and merits of various potential metals (Al, Mg, B, Be, or Zr) as a component of FRP are discussed. The paper also includes a discussion on the combustion mechanism of metallised propellants, including problem areas and probable remedial measures. Zirconium and Ti appear to have potential to offer FRP with efficient combustion. Ideal performance is not achieved with current systems based on Al and B and further work is needed to develop FRP having all three desirable attributes, viz., ease of ignition, stable combustion and high specific impulse (I/sub sp/) in a single composition

Influence of Aluminium on Performance of HTPB-based Aluminised PBXs

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

Rapid Estimation of Specific Impulse

Specific impulse (Isp) is one of the important criteria for propellant characterisation. In the present paper a semiempirical approach has been suggested to calculate Isp of composite modified doublebase(CMDB) propellant formulations by utilizing calorimetric value(Cal-Val) of the propellant composition. The Cal-Val of aluminium has been computed on the basis of oxygen balance of the propellant composition. The validity of the new approach has been demonstratedby comparing predicted values witli actual results

Effect of High Energy Materials on Sensitivity of Composite Modified Double Base CMDB Propellant System

The shock sensitivities (viz, impact and friction) of composite modified double-base (CMBD) ingredients, double-base (DB) matrix (SNC:CL) and the effect of high energy materials like ammonium perchlorate (AP), cyclotrimethylene trinitramine(RDX), cyclotetramethylene tetranitramine (HMX) and pentaerythritol tetranitrate (PTN) on a CMDB system, have been studied. Individual ingredients of DB matrix, i.e., spheroidal nitrocellulose (SNC) and desensitised nitroglycerine (casting liquid (CL), do not appear to be very sensitive to impact and friction, impact of 36.0 kg each. Various DB mixtures gave impact ranging between 56.5 to 61.5 cm and friction insensitivity of 36.0 kg for all the formulations. But addition of AP to DB matrix increases the impact and friction sensitivity tremendously, impact ranging from 15 to 24 cm and friction from 2.0 to 3.2 kg. Sensitivity-wise addition of RDX, HMX, and PETN to DB matrix follows AP while the addition of Al slightly reduces the sensitivity