Inhibited propellant

In the case of SB, DB and propellants, slow but autocatalytic decomposition of NC and NG takes place even at ambient temperatures. This is retarded by the addition of a stabilizer to these propellants and thus the compatibility and the stability or life of these propellants increases. The silvered vessel test and stabilizer consumption rate are the methods which are generally used to predict safe chemical life of propellants in Europe, USA, India and other countries. The migration of explosive plasticizer (NG) and non-explosive plasticizers ( , DEP) from propellants to inhibitors or vice-versa also affect the ballistics, mechanical properties and life of inhibited propellants. 

The inhibited propellants after conditioning at ambient, cold (-40 °C) and hot (+60 °C) temperatures, should give successful performance during static evaluation. This is the most important test and even if a polymer meets all the requirements but fails in this test, it cannot be used for inhibition of rocket propellants [282]. 

The inhibition of composite propellants is somewhat easier than that of DB propellants. The binders used for composite propellants (with or without fillers) have been reported for inhibition of composite propellants. Such inhibition systems possess stronger bonds with composite propellants and prove to be more compatible coupled with better shelf-life of the inhibited propellants. However, epoxy or novolac epoxy resin with or without inert fillers is generally preferred for the inhibition of composite propellants due to a combination of properties possessed by them. The inhibition is usually done by casting technique and inhibition thickness is usually required on higher side in order to make the missions successful. In India, thread winding technique or inhibitor sleeve technique is preferred where 2.5-3.0mm inhibition thickness is sufficient as against 3.5-4.0 mm in case of inhibition by casting technique . 

Ingolin = concentrated hydrogen peroxide (german) 23 inhabited building 138 inhibited propellant 191 305 Initialsprengstoffe = initiating explosives 135 191 initiation 191 initiator 94 191 injector nitration 227... 

Oberflachenbehandlung = surface treatment also -> inhibited propellant - restricted propellant 191 273 305 Obturate 239... 

Cigar burning. In propellants, the burning of a cylindrical charge from one end only, the other surfaces being inhibited. 

The combustion of H2, CO, and hydrocarbons with NO is important in both the dark zone and the flame zone of nitropolymer propellants. It is well known that NO behaves in a complex way in combustion processes, in that at certain concentrations it may catalyze a reaction to promote a process, while at other concentrations it may inhibit the reaction. Sawyer and GlassmanP attempted to estabUsh a measurable reaction between H2 and NO in a flow reactor at 0.1 MPa. Over a wide range of mixture ratios, they found that the reaction did not occur readily below the temperature of NO dissociation, except in the presence of some radicals. Mixtures of CO and NO are also difficult to ignite, and only mixtures rich in NO could be ignited at 1720 K. 

Kubota, N., and Hirata, N., Inhibition Reaction of liF on the Combustion of Ammonium Perchlorate Propellants,... 

The mechanical and physical properties of the inhibiting material must be fairly similar to those of the propellant in order to minimize the differential expansion. In this respect the use of several layers with possibly different compositions is favorable. With long burning timers (more than 20 sec) the development of a reliable inhibitor poses a fairly difficult problem, especially with end-burning grains. 

Inhibiting of Double-Base Catapult Propellants with Ethyl Cellosolve Gel Lacquers. Propellants for slotted tube catapults are designed to produce a const press system in the catapult tube. Catapult propellants usually have noncircular cross-sections and are completely externally inhibited... 

Gel lacquer formulations used for dip coating. The early catapult propellants were inhibited by dipping in a lacquer consisting of toluene 80p, acetone 20p and a total solids content of 15-18%. The grains were dipped twice and had a cured inhibitor thickness of 20 to 30 mils. As the size of experimental slotted tube catapults increased, coatings of 100 mils were required. This necessitated an increase of the solid content to 25-27%. As this soln was too viscous some methylol was incorporated in solvent formulation. In order to improve the room temp gelling characteristics an aliphatic hydrocarbon was added... 

Inhibiting Double Base Rocket Propellants at Picatinny Arsenal. Most of the work at Pica-tinny Arsn in connection with inhibiting of solventless extruded or cast double-base propellant has been with convolute wrappings of grains or tubes with cellulose acetate. There has been a trend toward use of extruded tubes made by the casting process... 

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