Toxic Hazard

Which is toxic and also is irritating to the eyes and lungs. Double-base propellants may produce lead combustion products in relatively low concentration, but these generally do not represent a toxic hazard. All propellants produce carbon monoxide, which is toxic. Beryllium and its water-soluble salts produce berylliosis, which is considered an allergenic disease the individual response may vary widely. The soluble salts of beryllium taken into the lungs are most likely to produce berylliosis....

Cws

A sHortest line distance from center of solid grain to periphery, cm 0 heat of decomposition, cal mole Z frequency factor activation energy, cal mole R gas constant, 1,98 cal mole- K T , critical temperature, K fc thermal conductivity, cal cm-sec-5K shape factor , Z, and E are deri 'ed from DTA measurements, A log-log plot of propellant radius vs. 1 T predicts cookoff temperatures for any given grain diameter. The time to ignition t, for any environmental temperature T is found by the inexact...

Spark Hazard

Under conditions of low humidity, an ungrounded human body can accumulate a static charge of as much as 0.015 joule (ref, 110). Any propellant with a spark sensitivity lower than this value may be initiated by contact with a human operator carrying a static charge. Propellants are exposed to mechanical devices with moving parts that may develop static charges. All equipment is grounded human operators wear grounding straps fixed to some part of the body and may wear conductive shoes. Grounding...

Sterilization

Prevention of terrestrial microbe contamination of space probes requires complete heat sterilization. The varying process times at 125' C needed for total sterilization of various geometries and sizes are described in reference 97, Sterilization time at 125 C for an 8-foot-radius shell required almost 51 hours. Requirements for sterilizing propellants may be as much as 300 hours at 275 F (ref. 98). Double-base binders arc excluded as sterilizable propellants. Polyurethane composite propellants...

Plasticizer Migration

The propellant plasticizer when equilibrated between propellant and liner shall not adversely affect the propelhmt-Hner bond. The liner-propellant bond and the insulation-propellant bond should be studied for plasticizer migration. Gas, liquid, or gas-liquid chromatography is recommended as the best technique for detecting very low concentrations of plasticizer in propellant sections analyzed for plasticizer migration. Sections of propellant along the grain radius may be analyzed, and a...

Info

CD 50 of samplr-s Hp'on rue or cli-flnRrate on Impact of 2-l- ff vHgh1 dropped frum a heiph measured In centimeters (see 2.0 2i, < 2 Kumltrr of O.OI-In. cellulose neetate cards nttenuatlnc test eliarRi* when Ot or 80H of eamples detonate ( ee 2.6 0). CD 50 of samplr-s Hp'on rue or cli-flnRrate on Impact of 2-l- ff vHgh1 dropped frum a heiph measured In centimeters (see 2.0 2i, < 2 Kumltrr of O.OI-In. cellulose neetate cards nttenuatlnc test eliarRi* when Ot or 80H of eamples detonate ( ee...

Mx Hmx Propellant

(1) CKF hM< l rat*. 2 In. mln. (1) CKF hM< l rat*. 2 In. mln. At higher temperatures (ca, 120 F), many propellants lose tensile strength and may flow or slump. Slump may represent a serious problem if propellant deformation affects the geometry and the internal ballistics of the motor, CTPB and PU propellants have tensile strengths in the 50 to 100 psi region at 120 F, Uncrosslinked PNC-DB propellants have tensile strengths in the 50 psi region at this temperature, and uncrosslinked...

Shelf Life

The propellant shall not be degraded below acceptable levels by required storage time and temperature. Existing data on type-life programs should be surveyed to determine whether service temperature aging data exist for a propellant similar to the one chosen. Service life data must be developed for the specific propellant in the end item if no type-life data are available. If the end item cannot be used, smaller motors designed to have analogous strain fields in the grain should be stored at...

Hazard Characterization

A propellant rarely is rejected simply because of its hazard characteristics. The results of hazard tests determine the degree of care to be exercised during the motor's manufacture, transportation, and storage. Many companies have developed propellant color codings that tell at a glance the propellant's relative sensitivity to initiation by impact, friction, or spark and its relati -e susceptibility to detonation. No single area of propellant characterization is more controversial than that of...

Ingredient Volatility

The propellant shall not be degraded below acceptable levels by the loss of volatile ingredients. The propellant suspected of having a volatile ingredient should be tested tor weight loss during exposure to vacuum. A series of tests covering the propellant temperature range should be run. The usual industry practice is to hold a propellant sample at 0.3 * Hg at 25 C for at least 240 hours. In addition to weight-loss measurements, it is recommended that mechanical properties be tested and...

Ldk

80 20 60 40 40 60 20 80 0 100 Oxidizer blend, coarse (190Ml fine (15 ) Figure 15. Effect of oxidizer grind on burning rate in PBAN propellants (ref, 52), Method (4), changing the oxidizer content, is applicable to all propellants as a method of modifying burning rate. However, a change in oxidizer content often has significant side effects. In particular, decreasing the oxidizer content to reduce burning rate may result in loss of combustion efficiency and loss of specific impulse increasing...

Distribution

Figure 2, Influence of propcllant properties on -weight of motor components. by physical fusion to an elastomeric propellant. Classical double-base propellants contain no crystalline oxidizer or metal they are composed of nitrocellulose gelled by a nitrate ester such as nitroglycerin and depend upon the nitro chemical groups in the nitrocellulose and nitrate ester for oxygen. The composite double-base propellants are based on the classical double-base binder but contain a crystalline oxidizer...

Autoignition Hazard

The propellant shall have an autoignition point so high that its probability of autoignition is low under the thermal environment to which it will be exposed. The propellant autoignition point should be characterized early in the program, preferably by the 1- and 2-in. cube technique. Heat-transfer anaylsis of the propellant under all storage and service conditions should establish that probable internal temperatures and their duration are below the autoignition point. It should be recognized,...

Measurement of Internal Ballistic Properties

The internal ballistic properties of the propellant in a motor shall be measured accurately under the anticipated service conditions. Burning rates should be measured over the pressure and temperature ranges of interest in internal-burning small motors as described in references 7 and 18, Crawford Bomb strand measurements may be used for preliminary screening, but the internal ballistic parameters used should be derived from motor measurements unless experience has shown that strand...

Space Environment

The propellant selected for extended exposure to a space environment shall not undergo physical, internal ballistic, or energetic changes when exposed to Propellants that may be exposed to vacuum should be based on a high-average-molecular-weight prepolymer. Where commercial binders are used, a high-molecular-weight fraction should be derived by molecular distillation or by solvent-nonsolvent precipitation ref. 98 . The propellant composition will present unusual outgassing problems if either a...

Impact Hazard

Many propellants can be ignited or detonated by impact. For this reason, it is important that the impact hazard of a propellant be characterized. The impact hazards of propellant ingredients, uncured propellant mixes, and cured propellant mixes have been characterized in the industry by a wide variety of impact devices. The most common principle for such a device Involves calibrated weight falling on a sample. No mechanical impact on a propellant is free of two secondary effects the effect of...

References

Anon, Development and Test of High Energy Solid Propellents. AFRPL TR 68204, Allegany Ballistics Laboratory, Nov. 1968. Confidential 2. Allabashi, J. C, Properties of Double-Base Propellants, Unpublished, 1969, Confidential 3. Shorr, M. and Zaehringer, A, J. Solid Rocket Technology, Ch. 2, John Wiley amp Sons, Inc., 1967. 4. Rumbel, K. E, Polyvinyl Chloride Plastisol Propellants. Paper presented at the Symposium on Manufacture, Hazards, and Testing of Propellants, 153rd National Meeting,...

Temperature Sensitivity of Burning Rate

The propeliant shall hove a temperature sensitivity of burning rate consistent with the requirements of the design and the anticipated thermal operating environment. The propeliant selected should have a low temperature sensitivity of burning rate, particularly in those designs where the thrust level must be held within narrow margins over wide ranges of temperature. When low temperature sensitivity is desirable, it is recommended that the propeliant selected have as low a pressure exponent as...

Uniaxial Tensile Properties

The propellant shall have stress and strain capability adequate to meet grain design requirements over the service temperature range. It is recommended that the most severe anticipated stress-strain condition in the grain be determined and expressed in terms of uniaxial properties by the use of an appropriate conversion factor, determined empirically for the propeilant of interest. The minimum allowable stress, strain, and modulus should be determined and the failure limits at all temperatures...

Bond Evaluation

The propellant-liner and liner-case bond shall he strong enough to withstand all anticipated stresses oi'er the ser 'ice temperature range. Bond tests using shear or bond-in-tension test mode should be run to evaluate various liner-propellant combinations. The peel test is not recommended because of ambiguities in its interpretation. Selection of a good liner-propellant combination should be based on data from tests that cover the temperature range of interest and include many liner candidates....

Solid Propellant Manual Cpia

Anon, Development and Test of High Energy Solid Propellants, AFRPL TR 68204, Allegany Ballistics Laboratory, Nov, 1968, Confidential 2. Allabashi, J. C, Properties of Double-Base Propellants, Unpublished, 1969, Confidential 3. Shorr, M. and Zaehringer, A. J. Solid Rocket Technology, Ch, 2. John Wiley amp Sons, Inc., 1967. 4. Rumbel, K. E, Polyvinyl Chloride Plastisol Propellants. Paper presented at the Symposium on Manufacture, Hazards, and Testing of Propellants, 153rd National Meeting,...

Thermal and Storage Stability

The propellant type shall have stability sufficient to withstand all anticipated thermal and chemical environments without unacceptable physical or chemical degradation during the required sen'ice life. The stability of the propellant should be characterized under all sen'ice conditions. Motors should be sealed in a dry atmosphere if the propellant is moisture-sensitive. If the propellant must be stored over a wide temperature range that includes extended periods above 140 F, a composite...