Ballistic properties

The combination of high strength, modulus, and toughness are some of the key factors for the candidate materials for high performance applications. The results of ballistic experiments showed that the required energy for penetrating PBO fabric was approximately twice that of Kevlar fabric [79]. 

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A. O. PaUingston and M. Weinstein, Method of Calculation of Interior Ballistic Properties of Propellantsfrom ClosedBomb Data, report 2005, PTA, Dover, N.J., 1959. 

Another class of hydrocarbon binders used in propints are the carboxy-terminated polybutadiene polymers which are cross-linked with either tris[l-(2-methyl)aziridinyl] phosphine oxide (MAPO) or combinations with phenyl bis [l -(2-methyl)aziridinyl] phosphine oxide (Phenyl MAPO). Phenyl MAPO is a difunctional counterpart of MAPO which makes possible chain extension of polymers with two carboxylic acid groups. A typical propint formulation with ballistic properties is in Table 11 (Ref 83) Another class of composites includes those using hydroxy-terminated polybutadienes cross-linked with toluene diisocyanate as binders. The following simplified equations illustrate typical reactions involved in binder formation... 

The composite propints are not the only ones subject to degradation processes which affect shelf-life, although they are relative newcomers to propint history. In NC-based pro pints, NC decomposes slowly to release NOa which reacts catalytically to hasten the degradation in physical and ballistic properties. To slow the process, stabilizing agents such1 as diphenylamine or 2-... 

Ballistic Properties of Black Powder , Explosives and Pyrotechnics (The Franklin Institute Research Laboratories) 4, No 1-3 (Jan-Mar 1971)... 

Brown, J.R., P.J.C. Chappell, Z. Mathys (1991), Plasma surface modification of advanced organic fibers part I. Effects on the mechanical, fracture and ballistic properties of aramid/aramid composites. J. Mater. Sci. 26. 4172 178,... 

Similar to nitramine composite propellants and TAGN composite propellants, AN composite propellants produce halogen-free combustion products and thus represent smokeless propellants. However, their ballistic properties are inferior to those of other composite propellants the burning rate is too low and the pressure exponent is too high to permit fabrication of rocket propellant grains. In addition, the mechanical properties of AN composite propellants vary with temperature due to the phase transitions of AN particles. 

The ballistic properties of ADN, HNF, and HNIW as monopropellants and as oxidizers in composite propellants have been extensively studied.P2-351 Since ADN, HNF, and HNIW particles produce excess oxygen among their combustion products, these particles are used as oxidizer crystals in composite propellants. The pressure exponents of crystalline ADN and HNIW particles are both approximately about the same value as those for HMX and RDX when they are burned as pressed pellets. However, the pressure exponent of HNF is 0.85-0.95,135] higher than those of the other energetic crystalline oxidizers. 

When HNF or ADN particles are mixed with a GAP copolymer containing aluminum particles, HNF-GAP and ADN-GAP composite propellants are formed, respectively. A higher theoretical specific impulse is obtained as compared to those of aluminized AP-HTPB composite propellants.However, the ballistic properties of ADN, HNIW, and HNF composite propellants, such as pressure exponent, temperature sensitivity, combustion instability, and mechanical properties, still need to be improved if they are to be used as rocket propellants. 

R.J. Blau, G. Chen et al, Moisture Resistant Black Powder Substitute, Methods for Its Production in Granular Form and the Resulting Ballistic Properties , AICHE Annual Meeting, San Francisco, CA, Nov 16-21, 2003. 

Target Practice (TP). This proj simulates the ballistic properties of service projs and is used for training in marksmanship. It may be made from completely inert-loaded service projs, or made from different metal parts and may contain a tracer and/or a spotting charge of BkPdr (Ref 52, p 1-33 1-34). Some TP projectiles used to be empty cast-iron shells (Ref 40b, p 4)... 

Hercopel a unique all-epoxide cure composite solid propellant with excellent mechanical and ballistic properties. Its outstanding performance in extended environments makes it well suited for tactical missiles Double-Base Solid Propellants a wide variety of physical and ballistic properties which can be tailored to meet specific performance requirements. Their high specific impulse and excellent reproducibility are two of the many reasons Hercules double-base propellants are found in many of our rocket motors and gas generators used for both military and space applications... 

From a practical standpoint, a system is considered cured when mechanical and ballistic properties show no further change with storage at cure temperature. However, propellant that is fully cured does not exhibit a perfectly homogeneous distribution of ingredients. 

In addition to the effects on physical properties, an effect on ballistic properties may also be observed. If the polymer does not fill the entire space not occupied by the solids, when ignited the flame front may proceed by connected voids to yield an uncontrolled combustion condition. A porous condition can have an effect on the sensitivity to detonation as discussed in Chapter 10. The attractive forces between polymer and solids are probably the major contributing factor that causes differences in physical properties of propellant and causes one polymeric or polymer-plus-plasticizer system to be preferred over another. 

Thermodynamic Calculations (Specific Impulse). Prepolymers in propellant binders keep the concentration of urethane groups small. Their effect on ballistic properties is therefore negligible and need not be considered in thermodynamic calculations. The contributions of the binder to specific impulse, density, etc., are determined by the chemical backbone structure of the prepolymer. [A more comprehensive treatment of interior ballistics can be found in References 37, 42.]... 

The most important attributes of this invention are high impulse performance coupled with high exit temperature on primary combustion and favorable boron species in the primary motor exhaust. The system is also insensitive to impact and possesses excellent thermal stability at elevated temperatures. Additionally, the system is readily castable since the addition of solid oxidizers is not required. Further, high flexibility in the ballistic properties of the gas generator can be achieved by the addition of solid oxidizers such as ammonium nitrate, ammonium perchlorate, hydroxylammonium perchlorate, potassium perchlorate, lithium perchlorate, calcium nitrate, barium perchlorate, RDX, HMX etc. The oxidizers are preferably powdered to a particle size of about 10 to 350 microns [13]. 

Specific impulse (Isp) is the most important single ballistic property for rocket propellants and its value is of utmost significance for the determination of propel-... 

Hamilton and coworkers designed a rocket propellant formulation based on BAMO-AMMO Copolymer TPE and 80% total solids (AP and Al) and it was directly cast into a phenolic case and required no liner or insulation. The results of firing of a 18 kg test motor exhibited completely acceptable ballistic properties. The authors claimed it to be the 1st demonstration of a high energy TPE motor firing [158]. Prior to this, Wardle and his team reported BAMO-AMMO copolymer and CL-20-based potentially attractive high energy ETPE gun propellants. 

A study was conducted to find out the effect of addition of these nitroplasticizers on ballistic properties of AP and RDX/HMX filled CMDB propellants. The data generated clearly indicated that the incorporation of nitroplasticizer, that is, 1 1 mixture of BDNPF and BDNPA in place of diethyl phthalate (DEP) for AP and nitramine based CMDB propellants improved the burn rates as well as /sp and thermal decomposition behavior of these propellant formulations [193]. 

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