Explosive properties of composite propellants

Composite propellants with elastomers (thiokol, polyurethane) do not detonate readily and this is due to their non-porous texture [29]. 

Most of the cast propellants charges also possess very high density and thanks to this they are difficult to detonate (e.g. Price and Jaffe [30]). They are prone to detonation when they are shredded and put into vessels of high degree of confinement [31]. 

Zaehringer, Solid Propellant Rockets, American Rocket Co., Wyandotte, 1955. 

Thiokol Chemical Corporation, Trenton 7, New Jersey, Liquid Polymer LP-31 and Liquid Polymers LP-2 and LP-32. 

Huggett, Combustion of Solid Propellants, Section M in Combustion Processes, Ed. B. Lewis, R. N. Pease and H. S. Taylor, Princeton University Press, Princeton, N.Y., 1956. 

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Burning composite propellants containing ammonium perchlorate Modifications of composite propellants (Mechanical profterties Manufacture of composite propellants Shapes of the propellant grains Explosive properties of composite propellants References... 

New method of mixing ingredients of composite propellants Various composite propellants and their characteristics Mixtures with ammonium picratc Explosive properties of composite propellants Literature... 

Triethylene glycol dinitrate (TEGDN) is an explosive plasticizer of low sensitivity that has been used in some nitroceUulose-base propellant compositions, often in combination with metriol trinitrate. Butanetriol trinitrate has been used occasionally as an explosive plasticizer coolant in propellants. Its physical properties are Hsted in Table 7. 

Explosives. Explosives can be detected usiag either radiation- or vapor-based detection. The aim of both methods is to respond specifically to the properties of the energetic material that distinguish it from harmless material of similar composition. A summary of techniques used is given ia Table 7. These techniques are useful for detecting organic as well as inorganic explosives (see Explosives and propellants). 

Rastogi K.. Kishore, Polymers as Fuel Binders in Composite Solid Propellant s , JSciindRes 32 (6), 279-99 (1973) CA 80, 121565 (1974) 32) A. Reiche , Changes in Properties of Polyester Explosives , JahrestaglnstChemTreib-Ex-plosivstFraunhofer-Ges 1971, 423-60 (1972)... 

Hydroxy-terminated polyester (HTPS) is made from diethylene glycol and adipic acid, and hydroxy-terminated polyether (HTPE) is made from propylene glycol. Hydroxy-terminated polyacetylene (HTPA) is synthesized from butynediol and paraformaldehyde and is characterized by acetylenic triple bonds. The terminal OH groups of these polymers are cured with isophorone diisocyanate. Table 4.3 shows the chemical properties of typical polymers and prepolymers used in composite propellants and explosives.E4 All of these polymers are inert, but, with the exception of HTPB, contain relatively high oxygen contents in their molecular structures. 

Since BAMO polymer is a solid at room temperature, BAMO monomer is copolymerized with tetrahydrofuran (THF) in order to formulate a liquid BAMO copolymer that is used as a binder in propellants and explosives, as shown in Fig. 4.9. The terminal OH groups of the BAMO-THF copolymer are cured by reaction with the NCO groups of hexamethylene diisocyanate (HMDl) and then cross-linking is carried out with trimethylolpropane (TMP). The physical properties of such a copolymer with a BAMO/THF composition of 60/40 mol% are shown in Table 4.7.1151... 

The physicochemical properties of explosives are fundamentally equivalent to those of propellants. Explosives are also made of energetic materials such as nitropolymers and composite materials composed of crystalline particles and polymeric materials. TNT, RDX, and HMX are typical energetic crystalline materials used as explosives. Furthermore, when ammonium nitrate (AN) particles are mixed with an oil, an energetic explosive named ANFO (ammonium nitrate fuel oil) is formed. AN with water is also an explosive, named slurry explosive, used in industrial and civil engineering. A difference between the materials used as explosives and propellants is not readily evident. Propellants can be detonated when they are subjected to excess heat energy or mechanical shock. Explosives can be deflagrated steadily without a detonation wave when they are gently heated without mechanical shock. 

Hydrocarbon polymers (HCP) are used not only as fuel components but also as binders of crystalline oxidizers and metal powders in the formulation of pyrolants, similar to composite propellants and plastic-bonded explosives. There are many types of HCP, the physicochemical properties of which are dependent on their molecular structures. The viscosity, molecular mass, and functionality of the poly-... 

There are many other ingredients that are added to explosive compositions which in themselves are not explosive but can enhance the power of explosives, reduce the sensitivity, and aid processing. Aluminium powder is frequently added to explosive and propellant compositions to improve their efficiency. Ammonium nitrate (NH4N03) is used extensively in commercial explosives and propellants. It is the most important raw material in the manufacture of commercial explosives and it also provides oxygen in rocket propellant compositions. Some of the properties of ammonium nitrate are presented in Table 2.22. 

The thermal properties of explosives and propellanl compositions are widely studied by DTA and DSC. Fauth (47) recorded the DTA curves of some hydrazine, guanidine and guanidinium picrates, slyphnates, and sulfates. The decomposition temperatures found were generally considerably lower than those reported in the literature. Other picrates, those with thallium, ammonium, tetramethylammonium, and letraethylammonium, were studied by Stammler (27). David (28) and Bohon (29) examined the thermal behavior of explosives and propellants under various external pressures up... 

Progressive development of high-temperature DTA has allowed the thermal characterization of materials such as ceramics and studies of molten inorganic salts as stable nonaqueous solvents in synthetic chemistry and to some extent in industry. This latter field has attracted increased interest recently in terms of its potential green chemistry overtones . Explosives, propellants, and pyrotechnics also form a major TA application area - particularly in terms of composition (phase diagrams) and thermochemical properties. 

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