Energetic plasticizers

Energetic plasticizers are defined as the liquid materials having a positive heat of explosion. Heat of explosion is the energy released by burning the propellant or ingredient in an inert atmosphere and then cooling to ambient temperatures in a fixed volume. 

Numerous plasticizers have been patented for use as energetic plasticizers in rocket propellants, pyrotechnics, explosives and munitions.  

The term plasticization is synonymous with gelatinization. It is used to describe the initial physico-chemical reaction of the polymer with the energetic plasticizer. By this reaction, the polymer and the energetic plasticizer form a soft colloidal dispersion. This dispersion is then made usable for propellant purposes by the application of mild heat over 

Compounds having the following formulas are used in these applications  

It is pertinent from these structiues that nitro arrd azide groups make plasticizers to have energetic properties. In addition to these plasticizers, also neutral plasticizers such as DOP and other plasticizers are used in these applications. The plasticizers or their combinations are selected to achieve the reqirired effect. Inert plasticizers usrrally lower the energy content of polymers used in explosives (e.g., nitrocellulose). 

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B. D. Strauss and co-workers, "New Energetic Plasticizers for LOVA PropeUants," in 3rd International Gun Propellant Symposium, Dover, N.J., Oct. 1984. 

Recent trends in rocket propint development and most of the recent developments in SP are for rocket and not gun proplnts, were directed toward the attainment of higher energy systems (actually higher specific impulse). Unfortunately, the use of exotic components presents grave stability problems which are yet to be overcome. Some energetic plasticizers have been developed and in some applications specific impulse has been increased substantially by substituting Be for Al. Much of this subject remains classified... 

The nitration of N,N -diethylurea gives nitrated products which are precursors for a new energetic plasticizer N,N -dialkyl-N,N -dinitrourea (DNDA). For macroscopic batch processing, this reaction is characterized by a lack of selectivity owing to mononitro derivative formation and thermal decomposition of the dinitro product due to increasing temperature during the course of reaction [37, 38]. 

Keywords Plasticizer, Energetic Plasticizers, Azido Plasticizers. 

Both 1,1-dinitroethane (26) and 1,1-dinitropropane, and their methylol derivatives, 2,2-dinitropropanol (25) and 2,2-dinitro-l-butanol respectively, have been synthesized via the Ter Meer reaction. - The formal and acetal of 2,2-dinitropropanol in the form of a 1 1 eutectic is an energetic plasticizer and so the synthesis of 2,2-dinitropropanol has been the subject of much investigation. On a pilot plant scale 2,2-dinitropropanol (25) is synthesized in 60 % overall yield from nitroethane (22). Thus, treatment of 1 -chloronitroethane (23) with potassium nitrite... 

A huge number of ester and carbonate derivatives of polynitroaliphatic alcohol have been synthesized driven by the search for new explosives and energetic plasticizers and oxidizers for propellant and explosive formulations. Most of these are derived from 2-fluoro-2,2-dinitroethanol and 2,2,2-trinitroethanol ° and have excellent oxygen balances. Some examples are illustrated above (168-174) but more comprehensive lists can be found in numerous reviews. " " Direct esterification of polynitroaliphatic alcohols with nitric acid, mixed acid, or acetic anhydride-nitric acid has been used as a route to mixed polynitroaliphatic-nitrate ester explosives. ... 

Some liquid nitro compounds have found past use in explosive compositions. A mixture of 2,4-dinitroethylbenzene and 2,4,6-trinitroethylbenzene, known as K-10, currently finds use as an energetic plasticizer in some propellant formulations. K-10 plasticizer, also known as Rowanite 8001, is manufactured by Royal Ordnance in the UK and also finds use as a plasticizer in PBXs. 

One simple example of chloride-catalyzed nitration is the synthesis of the energetic plasticizer Bu-NENA (34) from the nitration of n-butyl ethanolamine (33) with a mixture of acetic anhydride-nitric acid to which catalytic zinc chloride has been added. ... 

Agrawal and co-workers synthesized the energetic plasticizer bis(2-azidoethyl)adipate (2) (BAEA) from the reaction of bis(2-chloroethyl)adipate (1) with sodium azide in ethanol (72 %). 

Methyl-2-nitro-l-azidopropane (26), synthesized from the tosylate (25), has been suggested for use as an energetic plasticizer. ... 

Dinitroethylbenzene is a component of the energetic plasticizer known as K-10 (2 1 mixture of 2,4-dinitroethylbenzene and 2,4,6-trinitroethylbenzene). 

The reaction of aziridines and azetidine heterocycles with dinitrogen pentoxide in chlorinated solvents yields 1,2-nitramine nitrates and 1,3-nitramine nitrates respectively. In most cases yields are good to excellent, but, reactions are not as general as with the oxygen heterocycles the outcome of reactions is heavily dependent on the nature of the substituent on the exocyclic nitrogen. Some of the products from these reactions find use as melt-castable explosives i.e. Tris-X (46) and energetic plasticizers e.g. Bu-NENA (48) the latter is a component of some LOVA (low vulnerability ammunition) propellant formulations. 

Energetic plasticizers and binders for explosive and propellant compositions... 

Miscible with all energetic plasticizers in current use i.e., NG, DEGDN, TEGDN, MTN, K-10 and BDNPA/F etc. 

The energetic plasticizers also enhance flexibility and elasticity in addition to increase in the overall energy of a system and its spontaneous ignition properties. In explosives and propellants, they are preferred over non-energetic plasticizers... 

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