GB2371297A

GB2371297A - Propellant compositions and propellants produced therefrom

Info

Publication number: GB2371297A
Application number: GB8908714A
Authority: GB
Inventors: Ronald Benjamin Holt; John Charles Martin Phillips
Original assignee: Royal Ordnance PLC
Current assignee: BAE Systems Global Combat Systems Munitions Ltd
Priority date: 1989-04-18
Filing date: 1989-04-18
Publication date: 2002-07-24
Anticipated expiration: 2009-04-18
Also published as: GB2371297B; GB8908714D0

Abstract

An energetic composition suitable for use as a propellant comprises the following components in the following relative proportions:<BR> ```Component A: from 5% to 25% by weight of a polymeric binder;<BR> ```Component B: from 65% to 90% by weight of a highly energetic filler comprising at least one nitramine compound such as RDX, HMX or TATND; and<BR> ```Component C: from 1% to 15% by weight of a plasticiser which comprises at least one nitroaromatic compound such as nitrobenzene, nitrotoluene, nitrocresol or nitroxylese;<BR> ```the percentages by weight of Components A, B and C adding to 100%, wherein Component A comprises from 10 to 100 per cent by weight of a poly(ethylene/vinyl acetate), and may include nitrocellulose, cellulose acetate butyrate or other energetic or non-energetic binder materials.

Description

PROPELLANT COMPOSITIONS AND PROPELLANTS PRODUCED THEREFROM The present invention relates to propellant compositions and propellants produced therefrom.

Gun and rocket propellants have for many years been produced from compositions containing blends of nitrocellulose and nitroglycerine and are therefore known as double base materials. In some cases additional energetic ingredients such as picrite (nitroguanidine) are added and the propellants are known as triple base compositions. For high energy applications, eg. the propulsion of kinetic energy projectiles from an amoured tank gun, highly energetic components such as heteroalicyclic nitramines have been included in double and triple base compositions.

Double and triple base propellants, particularly for high energy applications, suffer from the disadvantage that they are highly vulnerable to unwanted ignition when subjected in a hostile environment to attack by an energetic projectile, e. g. a projectile comprising a shaped warhead charge.

Recent approaches to the problem of vulnerability of solid propellants have involved the development of compositions which are essentially non-double base or triple-base systems. Although such systems can pro reduced vulnerability this is, in general terms, obtained at the expense of propellant energy. Furthermore, the benefit of the addition of ingredients to compositions to reduce the vulnerability has been offset by the deleterious effect on other desirable properties, such as mechanical and processability properties.

It is an object of the present invention to provide improved solid propellant compositions for low vulnerability applications.

According to the present invention there is provided an energetic composition comprising the following components in the following relative proportions: Component A: from 5% to 25% by weight of a polymeric binder; Component B: from 65% to 90% by weight of a highly energetic filler comprising at least one nitramine compound; and Component C: from 1% to 15% by weight of a plasticiser which comprises at least one nitroaramatic compound; the percentages by weight of Components A, Rand C adding to 100%, wherein Component A comprises from 10 to 100 per cent by weight of a poly (ethylene/vinyl acetate) herein called"eva".

The term"eva"shall also be understood herein to include copolymers of ethylene/vinyl acetate and other monomer units.

In compositions according to the present invention, Component B essentially provides the high energy capability of the composition (although Component C makes and optionally Component A may make a minor contribution), Component B provides the required structural binder properties and Component C provides processibility enabling mixtures to be formed together with Components A and B and which may be worked into a suitable dough-like material which may be pressed, rolled or extruded to form suitable propellant products. The mutual combination of these components is specially selected in compositions according to the present invention because of the unexpected advantages such a combination provides as follows.

We have found that compositions according to the present invention can be suitably processed to provide propellant materials, eg. for use as gun or rocket propellants, especially gun propellants, which unexpectedly and beneficially can show an improved, ie. reduced vulnerability but without a corresponding decrease in energy normally associated with such an improvement which may be obtained together with a combination of other properties desirable of propellant materials.

The main properties which are desirable for a low vulnerability gun propellant, in addition to its reduced, vulnerability to shaped charge attack may be summarised as follows: (1) a good practical propellant force ; for example gun propellants for use in large calibre kinetic energy projectile applications should show a force of 1180KJ per Kg or more.

(2) a low rate of burn desirably less than 80mm per second; this allows stick propellants of reduced web size (as described below) to be used ; (3) a good resistance to shatter over a wide service temperature range especially at low temperatures, eg.-30 degrees C ; (4) good uniaxial mechanical properties ; preferably the material should be sufficiently flexible that sticks of it which are typically 200mm long may be readily bent by hand such that the ends of the sticks can be touched together without snapping the stick ; (5) a low flame temperature desirably less than 3000K ; this affords the possibility of reduced gun barrel errosion ; (6) the possibility of processing into a dough and extruding the dough using simple conventional processing solvents ; (7) the possibility of processing into a propellant product which shows little or no aeration with a density greater than 98%, preferably greater than 99 per cent, of its theoretical maximum density ; this allows more propellant to be packed into a given charge volume.

The propellant compositions embodying the invention are suitable for forming propellant products having unexpectedly all of aforementioned desirable properties.

Preferably Component A comprises from 10% to 20% by weight, Component B comprises 70% to 90% by weight and Component B comprises 8% to 15% by weight, of the said composition, the percentages adding to 100 per cent.

Component C preferably melts at a temperature less than 100 C and desirably is a liquid at room temperature (200C). Preferably, the said nitro compound is a monocyclic aromatic nitro compound; it may be a mono-nitro compound but preferably is a di-or tri-nitro compound or a mixture thereof.

Especially suitable as compounds for use in or as Component C are di-and tri-nitro alkyl-or alkoxy-benzenes optionally containing substituent groups in the aromatic ring or in the alkyl or alkoxy group. For example, the compound may be a di-or tri-nitro derivative of an optionally substituted alkyl-or alkoxy-benzene containing from 1 to 3 optionally substituted alkyl and/or alkoxy groups each having from 1 to 4 carbon atoms. The compound may for instance be a di-or tri-nitro derivative of an optionally substituted toluene, ethylbenzene, propylbenzene, butylbenzene, xylene, methylethylbenzene, diethylbenzene or mesitylene or one of the other families to which the compounds listed below belong.

As optional substituents for the aromatic ring in addition to nitro group (s) and alkyl or alkoxy group (s) where present in the said nitroaromatic compound (s) of Component C, are preferred groups other than halogens selected from OR, SH, N3,CO. OR3 or O. OCR where R,, R2, R3 and R4 are each independently H or a simple alkyl or alkoxy (containing from 1 to 4 carbon atoms) or phenyl.

Component C may for example comprise one or more of the following known compounds (where M. P./ C is the melting point in degrees Celsius): Compound No. Name M. P./0c

1 l-amino-2, 4-dimethyl-3-nitrobenzene 81-82 2 l-amino-3, 4-dimethyl-2-nitrobenzene 65-66 3 l-amino-3, 5-dimethyl-2-nitrobenzene 56 4 2-amino-l, 3-dimethyl-2-nitrobenzene 81-82 5 2-amino-l, 5-dimethyl-3-nitrobenzene 76 6 5-amino-l, 5-dimethyl-3-nitrobenzene 74-75 7 1-amino-2-methoxy-3-nitrobenzene 67 8 l, 3-dihydroxy-2-nitrobenzene 87-88 9 1, 2-dimethoxy-3-nitrobenzene 64-65 10 1, 2-dimethoxy-4-nitrobenzene 98 11 1, 3-dimethoxy-2-nitrobenzene 89 12 1, 4-dimethoxy-2-nitrobenzene 72-73 13 2, 4-dimethoxy-l-nitrobenzene 76-77 14 1, 2-dimethyl-3, 4-dinitrobenzene 82 15 1, 2-dimethyl-3, 5-dinitrobenzene 77 16 l, 3-dimethyl-2, 5-dinitrobenzene 101 17 l, 4-dimethyl-2, 3-dinitrobenzene 93 18 2, 3-dimethyl-l, 4-dinitrobenzene 89-90 19 1, 2-dimethyl-4-hydroxy-5-nitrobenzene 87 20 1, 3-dimethyl-2-hydroxy-4-nitrobenzene 99-100 21 1, 4 dimethyl-2-hydroxy-3-nitrobenzene 34-35

22 l, 5-dimethyl-2-hydroxy-3-nitrobenzene 73 23 1, 5-dimethyl-3-hydroxy-2-nitrobenzene 66-66. 5 24 2, 5-dimethyl-l-hydroxy-3-nitrobenzene 91 25 l, 2-dimethyl-3-nitrobenzene 15 26 1, 2-dimethyl-4-nitrobenzene 30-31

27 1, 3-dimethyl-2-nitrobenzene 13 28 l, 3-dimethyl-5-nitrobenzene 75 29 l, 4-dimethyl-2-nitrobenzene 30 2, 4-dimethyl-l-nitrobenzene 9 31 1, 3-dinitrobenzene 90 32 l, 3-dinitro-2-ethoxybenzene 59. 5-60. 5 33 l, 3-dinitro-5-ethoxybenzene 97. 5 34 l, 4-dinitro-2-ethoxybenzene 96-98 35 2, 4-dinitro-l-ethoxybenzene 86-87 36 1, 3-dinitro-5-isopropyl-4-hydroxy-6 55. 5 methylbenzene 37 1, 2-dinitro-4-methoxybenzene 71

38 1, 3-dinitro-5-methoxybenzene 205. 5 39 l, 4-dinitro-2-methoxybenzene 97 40 2, 4-dinitro-l-methoxybenzene 94. 5-95. 5 41 2, 4-dinitro-1, 3, 5-trimethyl-benzene 86 42 1-ethoxy-2-nitrobenzene 2 43 1-ethoxy-4-nitrobenzene 60 44 1-ethyl-2-nitrobenzene-23 45 1-ethyl-3-nitrobenzene-- 46 1-ethyl-4-nitrobenzene-12 47 1-isobutoxy-2-nitrobenzene (oil) 48 4-isopropyl-l-methyl-2-nitrobenzene 49 l-isopropyl-2-nitrobenzene 50 1-isopropyl-4-nitrobenzene-- 51 1-mercapto-2-nitrobenzene 58.5 52 1-mercapto-4-nitrobenzene 79 53 1-methoxy-2-nitrobenzene 10 54 1-methoxy-3-nitrobenzene 38-39 55 1-methxoxy-4-nitrobenzene 54 56 2-methoxy-l, 3,5-trinitrobenzene 69 57 nitrobenzene 5.7 58 1-nitro-2-triazobenzene 53-55 59 1-nitro-3-triazobenzene 56 60 1-nitro-4-triazobenzene 75 61 l-nitro-2, 3,5-trimethylbenzene 20 62 l-nitro-2, 4,5-trimethylbenzene 71 63 2-nitro-l, 3,5-trimethylbenzene 44 64 1, 2,4-trinitrobenzene 61-62 65 1, 3, 5-trinitrobenzene-- 66 N- (2-nitrophenyl) benzamide 98 67 2-nitrophenyl benzoate 85 68 3-nitrophenyl benzoate 71-72 69 4-nitrophenyl benzoate 94-95 70 2,4-dinitrotoluene 71 71 2,5-dinitrotoluene 53 72 2,6-dintirotoluene 66 73 3,4-dinitrotoluene 58 74 2,4-dinitro-6-hydroxytoluene 86 75 3, 5-dinitro-4-hydroxytoluene 85 76 2-hydroxy-3,4, 5-trinitrotoluene 102 77 3-hydroxy-2,4, 6-trinitrotoluene 109-110 78 2,4, 6-trinitrotoluene 82 Preferably, at least 50% by weight of Component C comprises one or more alkyl substituted monocyclic dinitrobenzenes, eg. selected from dinitrotoluenes, dinitroethylbenzenes and dinitropropylbenzenes.

Nitroaromatic compounds as described above have been found to provide energetic plasticisers which are compatible with nitramine energetic fillers and are highly suitable for use in processing mixtures of such fillers with polymeric binders. Preferably, the nitroaromatic plasticiser has an ignition temperature greater than 200 C.

Nitroaromatic compounds as described above are known or may be made well known methods.

For example, in the production of nitro derivatives of alkylbenzenes the appropriate alkylbenzene is treated with concentrated nitric and sulphuric acid at a temperature less than 40oC. Where the product obtained is a mixture of nitro compounds, eg. containing dinitroand trinitro derivatives, such a mixture may itself be suitable for use in or as Component C.

Although Component C desirably comprises one or more monocyclic nitroaromatic compounds, e. g. so that the monocyclic nitro compound (s) forms at least 50 per cent by weight of Component C, it may also include one or more aromatic nitro compounds containing more than one aromatic ring, e. g. one or more of the 2-esters listed above or one or more nitro derivatives of biphenyl, naphthalene diphenylmethane, bibenzyl or stilbene preferably containing two or three nitro groups in each ring. An example is 2, 2', 4, 4', 6, 6'-hexanitrostilbene.

Although Component C is preferably constituted entirely by nitroaromatic compounds as described above it could also include other energetic and non-energetic plasticisers as optional additives. For example, Component C may additionally include a quantity of one or more known energetic plasticisers such as GAP (glycidyl azide polymer), BDNPA/F (bis-2,2-dinitropropylacetol/formal), dimethylmethylene dinitroamine, bis (2,2, 2-trinitropropyl) formal, bis (2,2, 2-trinitroethyl) formal, bis (2-fluoro-2,2-dinitroethyl) formal, diethylene gylcol dinitrate, glycerol trinitrate, glycol trinitrate, triethylene glycol dinitrate, tetrethylene glycol dinitrate, trimethylolethane trinitrate, butanetriol trinitrate, or 1, 2,4-butanetriol trinitrate.

Alternatively, or in addition, Component C may include one or more known non-energetic plasticisers such as dialkyl esters or sebacic adipic or phthalic acid, eg. dibutyl phthalate, or diethyl phthalate, triacetin, tricresyl phosphate, polyalkylene glycols and their alkyl ether derivatives, eg. polyethylene glycol, polypropylene gycol, and diethylene glycol butylether. However, preferably at least 50% desirably at least 75% by weight of Component C is constituted by one or more nitroaromatic compounds.

In the composition according to the present invention Component A may be any suitable polymer binder which incorporates eva optionally together with other components. It may comprise an inert binder material, an energetic binder material or a blend of inert and energetic binder materials. However generally speaking, increasing the energetic nature of the binder increases the sensitiveness and explosiveness of the energetic material formed therefrom. Therefore employed binders which are energetic are desirably not highly energetic. For example where the binder comprises a blend of inert and energetic materials the inert material preferably forms at least 30% by weight of the binder.

Examples of suitable inert or non-energetic binder materials which may be blended with eva are cellulosic materials such as esters, eg. cellulose acetate, cellulose acetate butyrate, polyurethanes, polyesters, polybutadienes, polyethylenes, polyvinyl acetate and blends and/or copolymers thereof.

Examples of suitable energetic binder materials which may be blended with eva are nitrocellulose, polyvinyl nitrate, nitroethylene, nitroallyl acetate, nitroethyl acrylate, nitroethy methacrylate, trinitroethyl acrylate, dinitropropyl acrylate, C-nitropolystyrene and its derivatives, polyurethanes with aliphatic C-and N-nitro groups, polyesters made from dinitrocarboxylic acids and dinitrodiol.

We prefer for Component A cellulosic materials comprising 0 to 80 per cent by weight of nitrocellulose eg. containing 12 to 14 per cent by weight N, and 100 to 40 per cent by weight of an inert polymer at least 50% by weight of which is eva. The eva may for example be added to another cellulose ester, e. g. cellulose acetate or cellulose acetate butyrate.

Preferably the softening point of the binder Component A of the composition according to the present invention is greater than 60 C desirably greater than 80oC.

Preferably, the vinyl acetate content of the eva is in the range of 30 to 70 per cent by weight. The eva may comprise a mixture of polymers of different vinyl acetate content, eg. 40 per cent eva and/or 45 per cent eva and/or 60 per cent eva. For example, a typical polymer mixture may include 10 to 90 per cent by weight of a polymer having a 40 per cent by weight vinyl acetate content and 90 to 10 per cent by weight of a polymer having a 45 per cent by weight vinyl acetate content. Preferably a polymer mixture comprises more than 50 per cent by weight of an eva polymer having more than 40 per cent vinyl acetate content.

Preferably at least 75% by weight of Component A is constituted by one or more nitramine compounds. Nitramine compounds are those containing at least one heteroalicyclic ring containing N-NO2 groups. Such ring or rings may contain for example from two to ten carbon atoms and from two to ten ring nitrogen atoms. Examples of preferred heteroalicyclic nitramines are RDX (cycle-1, 3,5-trimethylene 2,4, 6-trinitramine, cyclonite or Hexagen), HMX

(cycle-1, 3, 5, 7-tetramethylene-2, 4, 6, 8-tetranitramine, Octogen) or TATND (tetranitro-tetraminodecalin) and mixtures thereof.

Preferably, Component B comprises from 50% to 100% by weight of RDX. Desirably, the composition includes from 70 to 85 per cent by weight of RDX.

Other highly energetic filler materials may optionally be added to the nitramine (s) of Component B, the non-nitramine component (s) providing up to 25 per cent by weight of Component A. Examples of suitable known highly energetic materials include picrite (nitroguanidine), TAGN, aromatic nitramines such as tetryl, ethylene dinitramine, and nitrate esters such as nitroglycerine (gylcerol trinitrate), butane triol trinitrate or pentaerythrital tetranitrate, and inorganic perchlorates and nitrates such as ammonium perchlorate optionally together with metallic fuel such as aluminium particles.

Various known additives may be added to the compositions according to the present invention comprising Components A, B and C as specified above. Preferably, the additive content comprises no more than 10 per cent by weight, desirably less than 5 per cent by weight, of the combined mixture when formed into a propellant.

The additive may for example comprise one or more

stabiliser, e. g. carbamite (N, N 1-diphenyl, NNl-diethylurea) or PNMA (para-nitro methylmethoxyaniline); and/or one or more ballistic modifiers, e. g. carbon black or lead salts; and/or one or more flash suppressants, e. g. one or more sodium or potassium salts, e. g. sodium or potassium sulphate or bicarbonate and one or more binder-to-energetic filler coupling agents and one or more antioxidants.

Preferred compositions embodying the invention for use as gun propellants comprise: eva 3 to 8 per cent by weight nitrocellulose 8 to 10 per cent by weight cellulose acetate butyrate 0 to 5 per cent by weight RDX 70 to 80 per cent by weight nitroaromatic plasticiser 5 to 13 per cent by weight dibutyl phthalate 0 to 5 per cent by weight carbamite stabiliser 0 to 1 per cent by weight minor additives (coupling agent antioxidant, flash suppressant, ballistic modifier) 0 to 5 per cent total In this composition, the nitroaramatic plasticiser is preferably selected from one of the following: (a) a mixture of dinitroethylbenzene and trinitroethylbenzene containing: dinitroethylbenzene 50-64 per cent by weight trinitroethylbenzene 36-50 per cent by weight ; (b) 2,4-dinitrotoluene ; (c) 4,6-dinitro-o-cresol ; (d) 2,4-dinitro-m-xylene ; Compositions according to the present invention may be processed into propellants by techniques which are known to those skilled in the art. The plasticiser comprising Component C is added to and absorbed by the polymer (or polymer blend) of Component A to swell and soften the polymer. If Component C includes a solid it may be melted and then added to Component A or added in a suitable solvent, eg. acetone or ethyl acetate. Component B, preferably in a paste with an organic solvent, is blended with a mixture of Components A and C in a suitable kneader to form a homogeneous composition. Eventually, the composition produced is pressed, rolled or extruded in the form of a dough-like material through suitably shaped extrusion dies. Extrusion may be carried out using a co-rotating twin screw extrusion machine.

The product obtained by extrusion of compositions according to the present invention may be obtained in any suitable form. For example, where the product is a gun propellant, it may be obtained in the form of sticks or granules of known shape. Sticks are usually formed by cutting to a suitable length rods or strands extruded through suitable dies giving a shape including a longitudinal slot. Granules are usually similarly formed by cutting to much shorter lengths rods or sticks obtained by extrusion. Normally, such granules have small holes, eg. seven holes running lengthwise therethrough to provide suitable burning surfaces.

An important feature of certain propellant products is the web size of the product shape or configuration.

This parameter, well known to those skilled in the propellants art, is the minimum thickness of propellant to be burnt through from one surface to another. For example, for a propellant product having simple tube configuration, the web thickness is the outer to inner wall thickness of the cross-sectional annulus of the tube. Web sizes of propellant products incorporating compositions embodying the invention may vary over a range according to the specific application, e. g. from 0.5mm to 4. 0mm, although the more desirable web sizes at the lower end of this range, e. g. from 0.5mm to 2. 0mm, will generally be suitable for most applications because the compositions generally have a low burning rate.

Examples of compositions embodying the invention and their use in the production of propellant materials will now be described.

In the following examples the appropriate Components A, B and C (as defined above) and their individual ingredients where made separately are prepared by known methods. These components are then formed into propellant products in the following general way which is known per se. The solid components comprising Component A and any minor additives, eg. stabiliser and/or flame suppressent, are loaded as a powder into an incorporator (blender) whose blades have previously been moistened with an organic solvent. The viscous liquid comprising Component C is added to a solvent eg. a simple organic liquid solvent such as ethanol, diethyl ether, acetone, ethyl acetate trichloroethane etc, and the mixture is poured into the incorporator to which further solvent is then added. The mixture is then incorporated together for 30 minutes after which further solvent is added and the mixture is subsequently further blended for 4 hours. Cold water is continuously run through the incorporator during blending.

After processing in the incorporator the mixture formed is dried in an oven at a temperature of typically 50-900C for a period of several hours and subsequently pressed or extruded into strands of the required cross-sectional shape and web size which are cut into appropriate lengths as will be readily apparent to those skilled in the art.

Products embodying the present invention comprising

compositions of the following components may be made in the manner described above. In the following compositions "Nitrocellulose"means nitrocellulose containing 12. 6% by weight N.

Composition 1

Component Ingredient Percentage by weight A) Nitrocellulose 10 ) EVA 6. 0 B) RDX 74 C) Plasticiser X 5. 0 ) Dibutyl phthalate 4. 5 Carbamite 0. 5

wherein : EVA is the material Elvax 40W (Trademark) supplied by Dupont which an eva polymer containing 40 weight per cent vinyl acetate.

Plasticiser X is a composition consiting of : 2, 6-dinitro-l-ethylbenzene 2 parts by weight 2, 4-dinitro-l-ethylbenzene 64 parts by weight 2, 4, 6-trinitro-l-ethylbenzene 34 parts by weight Composition 2

Component Ingredient Percentage by weight A) Nitrocellulose 8 ) EVA 4 ) Cellulose acetate 3 ) butyrate B RDX 72 C Plasticiser X 12. 5 Carbamite 0. 5

The advantageous properties of Composition 1 and 2 are summarised in Table 1 as follows : Table 1

Property Result for Result for Composition 1 Composition 2 Force 1184 KJ/Kg 1222KJ/Kg Ignition Temperature 1940C 1940C Rate of burn (mean) 77mm/sec 79mm/sec Shatter resistance 15 (Excellent) 14 (very good) rating Flexibility rating Excellent ; 20mm Excellent ; 20mm sticks may be readily sticks may be bent into a ring readily bent into a ring Aeration Nil Nil Density 99. 4% of theoretical 99. 6% of maximum theoretical maximum In Table 1 the shatter resistance rating number is the rating assigned to the stick propellant product after being fired under conditions simulating gun firing at -400C.

This is obtained by awarding an appropriate rating number (0-5) to the product after firing. Firings are carried out on three samples giving a total rating from 0 to 15. The number ratings for individual firings are assigned according to TABLE 2.

Thus, the shatter resistance number represents a measure of varying graded degrees of propellant break-up based on the number and size of surface flaws cracks or splits formed in the propellant grains. Thus the higher rating number the better the resistance to shattering.

TABLE 2

Physical Condition of Product After Firing Number Rating No visual deterioration 5 Surface flaws only with no cracks or deep 4 capillaries Minor crack or single deep capillary 2 Split grains, not more than two per fired sample 1 and/or multiple deep capillaries Split grains, more than two per fired sample 0

Claims

CLAIMS 1. An energetic composition suitable for use as a propellant comprising the following components in the following relative proportions: Component A: from 5% to 25% by weight of a polymeric binder ; Component B: from 65% to 90% by weight of a highly energetic filler comprising at least one nitramine compound ; and Component C: from 1% to 15% by weight of a plasticiser which comprises at least one nitroaromatic compound ; the percentages by weight of Components A, B and C adding to 100%, wherein Component A comprises from 10 to 100 per cent by weight of a poly (ethylene/vinyl acetate).
2. A composition as claimed in claim 1 and wherein Component A comprises from 10% to 20% by weight, Component B comprises 70% to 90% by weight and Component B comprises 8% to 15% by weight, of the said composition, the percentages adding to 100 per cent.
3. A composition as claimed in claim 1 or claim 2 and wherein Component C melts at a temperature less than 1000C, the said nitro compound being a monocyclic aromatic nitro compound.
4. A composition as claimed in any one of the preceding claims and which comprises the following ingredients: poly (ethylene/vinyl acetate) 3 to 8 per cent by weight nitrocellulose 8 to 10 per cent by weight cellulose acetate butyrate 0 to 5 per cent by weight RDX 70 to 80 per cent by weight nitroaromatic plasticiser 5 to 13 per cent by weight dibutyl pthalate 0 to 5 per cent by weight carbamite stabiliser 0 to 1 per cent by weight minor additives 0 to 1 per cent by weight the total percentages of the ingredients adding to 100 per cent.
5. A composition as claimed in claim 4 and wherein the nitroaromatic plasticiser comprises one or more compounds selected from: (a) a mixture of dinitroethylbenzene and trinitroethylbenzene containing: dinitroethylbenzene 50-64 per cent by weight trinitroethylbenzene 36-50 per cent by weight; (b) 2,4-dinitroluene (c) 4,6-dinitro-o-cresol ; (d) 2,4-dinitro-m-xylene.
6. A gun propellant comprising sticks of any one of the compositions claimed in claims 1 to 5.

6. A gun propellant comprising sticks of any one of the compositions claimed in claims 1 to 5.

Amendments to the claims have been filed as follows

1. An energetic composition suitable for use as a propellant comprises the following components in the following relative proportions : Component A : from 5% to 25% by weight of a polymeric binder; Component B: from 65% to 90% by weight of a highly energetic filler comprising at least one nitramine compound; and Component C: from 1% to 15% by weight of a plasticiser which comprises at least one nitroaromatic compound; the percentages by weight of Components A, B and C, together with minor additives, if any, adding to 100%, wherein component A comprises from 10 to 100 per cent by weight of a poly (ethylene/vinyl acetate).

2. A composition as claimed in claim 1 and wherein Component A comprises from 10% to 20% by weight, Component B comprises 70% to 90% by weight and Component C comprises 8% to 15% by weight, of the said composition, the percentages adding to 100 per cent.

3. A composition as claimed in claim 1 or claim 2 and wherein Component C melts at a temperature less than 100oC, the said nitro compound being a monocyclic aromatic nitro compound.

4. A composition as claimed in any one of the preceding claims and which comprises the following ingredients: forming at least a part of Component A: - poly (ethylene/vinyl acetate 3 to 8 per cent by weight - nitrocellulose 8 to 10 per cent by weight - cellulose acetate butyrate 0 to 5 per cent by weight forming at least a part of Component B: - RDX 70 to 80 per cent by weight forming at least a part of Component C: - nitroaromatic plasticiser 5 to 13 per cent by weight - dibutyl pthalate 0 to 5 per cent by weight as optional minor additives: - carbamite stabiliser 0 to 1 per cent by weight - other minor additives 0 to 1 per cent by weight the total percentages of the ingredients adding to 100 per cent. 5. A composition as claimed in claim 4 and wherein the nitroaromatic plasticiser comprises one or more compounds selected from: (a) a mixture of dinitroethylbenzene and trinitroethylbenzene containing: dinitroethylbenzene 50-64 per cent by weight trinitroethylbenzene 36-50 per cent by weight; (b) 2,4-dinitroluene (c) 4, 6-dinitro-o-cresol ; (d) 2,4-dinitro-m-xylene.