US3658608A - Hydrazinium nitroformate propellant stabilized with nitroguanidine - Google Patents
Hydrazinium nitroformate propellant stabilized with nitroguanidine Download PDFInfo
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- US3658608A US3658608A US74861A US3658608DA US3658608A US 3658608 A US3658608 A US 3658608A US 74861 A US74861 A US 74861A US 3658608D A US3658608D A US 3658608DA US 3658608 A US3658608 A US 3658608A
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- propellant
- binder
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- nitroguanidine
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- XYODKMYYACGWBN-UHFFFAOYSA-N aminoazanium;nitroformate Chemical compound [NH3+]N.[O-]C(=O)[N+]([O-])=O XYODKMYYACGWBN-UHFFFAOYSA-N 0.000 title claims abstract description 10
- IDCPFAYURAQKDZ-UHFFFAOYSA-N 1-nitroguanidine Chemical compound NC(=N)N[N+]([O-])=O IDCPFAYURAQKDZ-UHFFFAOYSA-N 0.000 title claims description 24
- 239000003380 propellant Substances 0.000 title description 24
- 239000000203 mixture Substances 0.000 claims abstract description 44
- 239000011230 binding agent Substances 0.000 claims abstract description 39
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims abstract description 18
- 239000004449 solid propellant Substances 0.000 claims abstract description 16
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 11
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 11
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 11
- 239000003795 chemical substances by application Substances 0.000 claims description 15
- 239000005062 Polybutadiene Substances 0.000 claims description 12
- 229920002857 polybutadiene Polymers 0.000 claims description 12
- 239000000446 fuel Substances 0.000 claims description 8
- 239000007787 solid Substances 0.000 claims description 8
- IUCJMVBFZDHPDX-UHFFFAOYSA-N tretamine Chemical group C1CN1C1=NC(N2CC2)=NC(N2CC2)=N1 IUCJMVBFZDHPDX-UHFFFAOYSA-N 0.000 claims description 8
- 229950001353 tretamine Drugs 0.000 claims description 8
- 239000004014 plasticizer Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- 239000007800 oxidant agent Substances 0.000 abstract description 7
- 238000010348 incorporation Methods 0.000 abstract description 2
- 239000000463 material Substances 0.000 description 10
- 238000009472 formulation Methods 0.000 description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- 229930195735 unsaturated hydrocarbon Natural products 0.000 description 5
- 230000006866 deterioration Effects 0.000 description 3
- 150000002148 esters Chemical class 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000003921 oil Substances 0.000 description 3
- 230000008961 swelling Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229920000877 Melamine resin Polymers 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- GHMLBKRAJCXXBS-UHFFFAOYSA-N resorcinol Chemical compound OC1=CC=CC(O)=C1 GHMLBKRAJCXXBS-UHFFFAOYSA-N 0.000 description 2
- RUKISNQKOIKZGT-UHFFFAOYSA-N 2-nitrodiphenylamine Chemical compound [O-][N+](=O)C1=CC=CC=C1NC1=CC=CC=C1 RUKISNQKOIKZGT-UHFFFAOYSA-N 0.000 description 1
- GBLPOPTXAXWWPO-UHFFFAOYSA-N 8-methylnonyl nonanoate Chemical compound CCCCCCCCC(=O)OCCCCCCCC(C)C GBLPOPTXAXWWPO-UHFFFAOYSA-N 0.000 description 1
- NOWKCMXCCJGMRR-UHFFFAOYSA-N Aziridine Chemical compound C1CN1 NOWKCMXCCJGMRR-UHFFFAOYSA-N 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N Nitrogen dioxide Chemical class O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 239000007983 Tris buffer Substances 0.000 description 1
- AVUYXHYHTTVPRX-UHFFFAOYSA-N Tris(2-methyl-1-aziridinyl)phosphine oxide Chemical compound CC1CN1P(=O)(N1C(C1)C)N1C(C)C1 AVUYXHYHTTVPRX-UHFFFAOYSA-N 0.000 description 1
- 240000008042 Zea mays Species 0.000 description 1
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 1
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 235000005822 corn Nutrition 0.000 description 1
- XWVQUJDBOICHGH-UHFFFAOYSA-N dioctyl nonanedioate Chemical compound CCCCCCCCOC(=O)CCCCCCCC(=O)OCCCCCCCC XWVQUJDBOICHGH-UHFFFAOYSA-N 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- HFPDJZULJLQGDN-UHFFFAOYSA-N hydrazine;perchloric acid Chemical compound [NH3+]N.[O-]Cl(=O)(=O)=O HFPDJZULJLQGDN-UHFFFAOYSA-N 0.000 description 1
- BMMNWPYKMOFBBE-UHFFFAOYSA-N hydroxylamine;perchloric acid Chemical compound ON.OCl(=O)(=O)=O BMMNWPYKMOFBBE-UHFFFAOYSA-N 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- QCOXCILKVHKOGO-UHFFFAOYSA-N n-(2-nitramidoethyl)nitramide Chemical compound [O-][N+](=O)NCCN[N+]([O-])=O QCOXCILKVHKOGO-UHFFFAOYSA-N 0.000 description 1
- 150000002828 nitro derivatives Chemical class 0.000 description 1
- LAZVTKQYCZFNSZ-UHFFFAOYSA-N nitro formate Chemical compound [O-][N+](=O)OC=O LAZVTKQYCZFNSZ-UHFFFAOYSA-N 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- AUONHKJOIZSQGR-UHFFFAOYSA-N oxophosphane Chemical compound P=O AUONHKJOIZSQGR-UHFFFAOYSA-N 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920001083 polybutene Polymers 0.000 description 1
- 229920001195 polyisoprene Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920005596 polymer binder Polymers 0.000 description 1
- 239000002491 polymer binding agent Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- AGCQZYRSTIRJFM-UHFFFAOYSA-N triethylene glycol dinitrate Chemical compound [O-][N+](=O)OCCOCCOCCO[N+]([O-])=O AGCQZYRSTIRJFM-UHFFFAOYSA-N 0.000 description 1
- IPPYBNCEPZCLNI-UHFFFAOYSA-N trimethylolethane trinitrate Chemical compound [O-][N+](=O)OCC(C)(CO[N+]([O-])=O)CO[N+]([O-])=O IPPYBNCEPZCLNI-UHFFFAOYSA-N 0.000 description 1
- SXYOAESUCSYJNZ-UHFFFAOYSA-L zinc;bis(6-methylheptoxy)-sulfanylidene-sulfido-$l^{5}-phosphane Chemical compound [Zn+2].CC(C)CCCCCOP([S-])(=S)OCCCCCC(C)C.CC(C)CCCCCOP([S-])(=S)OCCCCCC(C)C SXYOAESUCSYJNZ-UHFFFAOYSA-L 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B47/00—Compositions in which the components are separately stored until the moment of burning or explosion, e.g. "Sprengel"-type explosives; Suspensions of solid component in a normally non-explosive liquid phase, including a thickened aqueous phase
- C06B47/02—Compositions in which the components are separately stored until the moment of burning or explosion, e.g. "Sprengel"-type explosives; Suspensions of solid component in a normally non-explosive liquid phase, including a thickened aqueous phase the components comprising a binary propellant
- C06B47/08—Compositions in which the components are separately stored until the moment of burning or explosion, e.g. "Sprengel"-type explosives; Suspensions of solid component in a normally non-explosive liquid phase, including a thickened aqueous phase the components comprising a binary propellant a component containing hydrazine or a hydrazine derivative
Definitions
- This invention is in the field of solid propellant compositions. More particularly, the invention relates to improved solid propellant composition containing hydrazinium nitroformate and unsaturated carboxyl terminated hydrocarbon binder.
- HNF Hydrazinium nitroformate
- binders utilized in solid propellants is carboxyl terminated polybutadiene. This binder has a plurality of double bonds in the backbone. It has been found that HNF cannot be satisfactorily utilized with binders containing such double bonds, since it appears that HNF attacks the backbone of the binder, breaking down the binder chain. Pockets of gas are formed andthe propellant thus swells. Further, due to the breakdown of the binder backbone, the material becomes soft. Thus, where a binder containing double bonds is utilized, a typical shelf life with HNF will range from 2 to days at a temperature of 70-90 F. Such a short shelf life prevents practical utilization of HNF with binders containing double bonds.
- HNF HNF in solidpropellants
- MAPO aziridine type of curing agent
- a curing agent such as triethyelene melamine which is not susceptible to reaction with the HNF.
- the herein invention is based upon the discovery that if a relatively small amount of nitroguanidine is added to solid propellant formulations having unsaturated hydrocarbon binders and containing HNF, then the shelf life of the propellant is significantly increased. Thus, unexpectedly it has been discovered that if at least 2 weight percent of the nitroguanidine is utilized, the shelf life of the propellant containing HNF canbe increased up to at least 5 months at ambient temperatures.
- the nitroguanidine is added to the propellant during its mixing phase and will remain in the composition to prevent the undesirable reaction of the HNF with the binder. It is believed the invention will be further understood from the following detailed description and example:
- HNF though being a very energetic oxidizer, appears to attack the'doublebonds that exist in various hydrocarbon binders utilized in solid propellants. The result of this attack is the production of a gas which swells the propellant, making it spongy or porous. The material is then no longer utilizable for rocket motors, since it will have completely unpredictable burning rates. Further, the strength of the propellant is so greatly weakened that it cannot sustain the high g-loads encounteredin rocket motors without further disintegrating.
- the most typical binder that is utilized with HNF is carboxyl terminated polybutadiene.
- polyisoprene which also contains double bonds susceptible to attack by the HNF.
- solid oxidizers known to attack solid unsaturated binders, such as hydroxylamine perchlorate and hydrazine perchlorate. These other oxidizers however are not as energetic as HNF and thus the herein invention is not directed toward preventing the attack of these materials upon the unsaturated binders. These other materials are merely illustrative of the existence of the herein problem in solid propellant systems.
- a typical solid propellant formulation utilizing HNF as a solid particulate oxidizer will contain on the order of 50 to 65 weight percent. of the material.
- the unsaturated hydrocarbon binder will comprise from 5 to 25 weight percent.
- a solid particulate fuel such as aluminum, ranging from 5 to 20 weight percent.
- Propellant compositions will preferably additionally contain other materials, such as plasticizers, including hydrocarbon oils, certain esters and some nitro compounds which can range from 0 to 20 weight percent.
- hydrocarbon oils are Conoco H-35, a product of Continental Oil Co. and Oronite Polybutene No. 6, a product of California Chemical Co.
- Esters in order to be miscible with the hydrocarbon polymer binder, must have a carbon to oxygen ratio of about 3 to l or higher. Dioctyl azelate and isodecyl pelargonate are typical of the preferred esters.
- Nitro and nitrato compounds also are not soluble to a great extent in the polybutadiene binder when the carbon to oxygen ratio is less than about 3 to 1.
- the low solubility of triethylene glycol dinitrate and trimethylol ethane trinitrate where the c/o ratio is less than 1 to l limits their use to less than 5 parts per parts of the polymer.
- a solidpropellant containing HNF will decompose within a relatively short time at ambient conditions.
- shelf life can be increased to the point where the propellant is use ful.
- at least 2 weight percent of nitroguanidine is required in the propellant formulation. This amount can vary up to 20 weight percent of the formulation, at which point no further improvement in propellant stability is seen upon further addition of the nitroguanidine.
- Nitroguanidine has been previously added to various solid propellant compositions mainly to serve as a means to control the burning rate of the propellant.
- the nitroguanidine however performs unexpected results, since other similar materials which have been tried do not affect the reaction of HNF with the binder at all or to a minor degree as compared to the nitroguanidine.
- two nitrocellulose stabilizers, ethyl contralite and 2-nitrodiphenylamine when added to the composition herein in fact increased the rate of deterioration of the HNF containing propellants.
- Another material that had been added was resorcinol, which in some tests appeared to slightly increase the shelf life but was not nearly as effective as the nitroguanidine.
- Various other materials that had also been tested had no effect, or in fact accelerated the deterioration.
- unexpectedly nitroguanidine inhibited the reaction of the HNF with the binder to provide a useful propellant composition.
- the nitroguanidine is obtained in a powder form and can be added at any time during the mixing of the propellant ingredients.
- the binder and plasticizer are first mixed with the fuel then the oxidizer is added thereto.
- the nitroguanidine is often added with the fuel.
- a propellant formulation was made by mixing in weight percent l0.92 percent of carboxy terminated polybutadiene, 0.34 weight percent triethylene melamine, 4.74 percent Conoco l-l-35, which is a hydrocarbon oil with a low viscosity, 16 percent aluminum powder, and 68 percent HNF.
- the carboxy terminated polybutadiene, plasticizer and aluminum fuel were mixed for five minutes in a Baker-Perkins vertical mixer.
- the HNF was added thereto in three increments, mixing for 10 minutes after each addition.
- the curing agent was added and mixing was continued for 10 minutes in vacuum to obtain a void-free mix.
- This propellant cured in about 24 hours at ambient temperature. Swelling and porosity of the propellant mixture became evident after 6 days at ambient temperature.
- EXAMPLE ll A composition containing 13.9 weight percent carboxyl terminated polybutadiene, 0.6 weight percent triethylene melamine, 3.5 weight percent Conoco H-35, l percent aluminum powder and 62 percent HNF was formulated as described in Example I. To this composition during the mixing thereof was added 10 percent nitroguanidine. The propellant was cast into plastic containers which had a length to diameter ratio of 3. The propellant cured in about 24 hours at ambient temperature then was stored at ambient temperature and was examined frequently.
- the above formulation of this example showed no deterioration such as swelling or softening after 5 months storage at ambient temperatures.
- nitroguanidine unexpectedly and peculiarly serves to inhibit a reaction between HNF and unsaturated hydrocarbon binders, particularly carboxyl terminated polybutadiene.
- HNF unsaturated hydrocarbon binders
- carboxyl terminated polybutadiene carboxyl terminated polybutadiene.
- No theoretical explanation for the effect of nitroguanidine has been developed. The possibility that the stabilizing effect might be due to the nitramino group (--NHNO was considered. Ethylene dinitramine, containing two of these groups. however, was not effective.
- a solid propellant composition comprising:
- hydrazinium nitroformate is an amount sufficient to act as an oxidizer
- nitroguanidine as an amount sufficient to improve the shelf life of the composition.
- composition of claim 1 wherein said binder is carboxyl terminated polybutadiene.
- composition of claim 1 wherein said curing agent is triethylene melamine.
- composition of claim 1 further comprising:
- composition of claim 5 further comprising:
- composition of claim 6 wherein said binder is carboxyl terminated polybutadiene.
- composition of claim 7 wherein said curing agent is triethylene melamine.
- composition of claim 5 additionally comprising:
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Abstract
The stability of solid propellant compositions containing unsaturated carboxyl terminated hydrocarbon binders and hydrazinium nitroformate as an oxidizer will have improved shelf life and stability through the incorporation of nitroquanidine in the mixture.
Description
United States Patent Low et al. [4 1 Apr. 25, 1972 1541 HYDRAZINIUM NITROFORMATE [56] References Cited PROPELLANT STABILIZED WITH UNITED STATES PATENTS NITROGUANIDINE 3,046,829 7/1962 Roemer ..l49/I9 X [72] Inventors: George M. Low, Deputy Admlmstrator of 3,147,161 9 9 Abel-e et #14956 x the National Aeronautics and Space Ad- 3 305 523 2 19 7 Burnside 9 19 X ministration with respect I9 an invention 3,418,183 12/1968 Rice ...149/19 x Vernon y, 5059 Alta Street, 3,476,622 11/1969 Harada eta]. ..149/19 Santa Susan, Calif. 93063 22 t. 1 7 Primary Examiner-Carl D. Quarforth 1 sep 9 0 Assistant Examiner-15. A. Miller [2]] Appl. No.: 74,861 Attorney-Monte F. Mott,J.H.Warden and John R. Manning [52] US. Cl ..149/19, 149/20, 149/36, [57] ABSTRACT 149/92 The stability of solid propellant compositions containing un- [5l] lnt.Cl. ..C06d 5/06 saturated carboxyl terminated hydrocarbon binders and [58] Field of Search ..l49/l9, 36, 92, 20, 88 hydrazinium nitroformate as an oxidizer will have improved shelf life and stability through the incorporation of nitroquanidine in the mixture.
9 Claims, No Drawings HYDRAZINIU M NITROFORMATE PROPELLANT STABILIZED WITH NITROGUANIDINE ORIGIN or THE INVENTION The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Actof 1958, Public Law 83-568 (72 Stat. 435; 42 USC 2457).
BACKGROUND OF THE INVENTION 1 Field of the Invention This invention is in the field of solid propellant compositions. More particularly, the invention relates to improved solid propellant composition containing hydrazinium nitroformate and unsaturated carboxyl terminated hydrocarbon binder.
2. Description of the Prior Art Hydrazinium nitroformate, HNF, is a very desirable oxidizer for use in solid propellant formulations because it is very energetic, thus providing high performance. One of the most popular binders utilized in solid propellants is carboxyl terminated polybutadiene. This binder has a plurality of double bonds in the backbone. It has been found that HNF cannot be satisfactorily utilized with binders containing such double bonds, since it appears that HNF attacks the backbone of the binder, breaking down the binder chain. Pockets of gas are formed andthe propellant thus swells. Further, due to the breakdown of the binder backbone, the material becomes soft. Thus, where a binder containing double bonds is utilized, a typical shelf life with HNF will range from 2 to days at a temperature of 70-90 F. Such a short shelf life prevents practical utilization of HNF with binders containing double bonds.
An additional problem in utilizing HNF in solidpropellants isthatit will attackmany of the typical curing agents utilized. Particularly it is found that the HNF will attack the aziridine type of curing agent, such as MAPO, which is tris[1-(2- methyU-aziridinyl] phosphine oxide. One can overcome the problem of the'HNF attack on the curing agent by utilizing a curing agent such as triethyelene melamine which is not susceptible to reaction with the HNF. However, it is not possi ble to readily select amore suitable binder than the carboxyl terminatedpolybutadiene. As a result, in order to have a practical system, additionalmeansisrequired to prevent reaction between theHN F andthe unsaturated hydrocarbon binder.
SUMMARY OF THE INVENTION The herein invention is based upon the discovery that if a relatively small amount of nitroguanidine is added to solid propellant formulations having unsaturated hydrocarbon binders and containing HNF, then the shelf life of the propellant is significantly increased. Thus, unexpectedly it has been discovered that if at least 2 weight percent of the nitroguanidine is utilized, the shelf life of the propellant containing HNF canbe increased up to at least 5 months at ambient temperatures. The nitroguanidine is added to the propellant during its mixing phase and will remain in the composition to prevent the undesirable reaction of the HNF with the binder. It is believed the invention will be further understood from the following detailed description and example:
DESCRIPTION OF THE PREFERRED EMBODIMENTS As has been pointed out, HNF, though being a very energetic oxidizer, appears to attack the'doublebonds that exist in various hydrocarbon binders utilized in solid propellants. The result of this attack is the production of a gas which swells the propellant, making it spongy or porous. The material is then no longer utilizable for rocket motors, since it will have completely unpredictable burning rates. Further, the strength of the propellant is so greatly weakened that it cannot sustain the high g-loads encounteredin rocket motors without further disintegrating. The most typical binder that is utilized with HNF is carboxyl terminated polybutadiene. Another binder which is useful, but not as preferred is polyisoprene, which also contains double bonds susceptible to attack by the HNF. There are other solid oxidizers known to attack solid unsaturated binders, such as hydroxylamine perchlorate and hydrazine perchlorate. These other oxidizers however are not as energetic as HNF and thus the herein invention is not directed toward preventing the attack of these materials upon the unsaturated binders. These other materials are merely illustrative of the existence of the herein problem in solid propellant systems.
A typical solid propellant formulation utilizing HNF as a solid particulate oxidizer will contain on the order of 50 to 65 weight percent. of the material. The unsaturated hydrocarbon binder will comprise from 5 to 25 weight percent. Additionally, there will be a solid particulate fuel such as aluminum, ranging from 5 to 20 weight percent. Propellant compositions will preferably additionally contain other materials, such as plasticizers, including hydrocarbon oils, certain esters and some nitro compounds which can range from 0 to 20 weight percent. Representative of hydrocarbon oils are Conoco H-35, a product of Continental Oil Co. and Oronite Polybutene No. 6, a product of California Chemical Co. Esters, in order to be miscible with the hydrocarbon polymer binder, must have a carbon to oxygen ratio of about 3 to l or higher. Dioctyl azelate and isodecyl pelargonate are typical of the preferred esters.
Nitro and nitrato compounds also are not soluble to a great extent in the polybutadiene binder when the carbon to oxygen ratio is less than about 3 to 1. Thus, the low solubility of triethylene glycol dinitrate and trimethylol ethane trinitrate where the c/o ratio is less than 1 to l limits their use to less than 5 parts per parts of the polymer.
Further, a small amount varying from 0.2 to 1.0 weight percent of the curing agent, preferably triethylene melamine, is present to cross link the unsaturated hydrocarbon binder. It is particularly preferred to use the melamine as a curing agent since it neither attacks or reacts with HNF, unlike other various conventional curing agents that are used with the unsaturatedbinders.
Without further additive materials, the above general compositionof a solidpropellant containing HNF will decompose within a relatively short time at ambient conditions. However, upon the addition of nitroguanidine tothe'formulation, shelf life can be increased to the point where the propellant is use ful. It has been found that at least 2 weight percent of nitroguanidine is required in the propellant formulation. This amount can vary up to 20 weight percent of the formulation, at which point no further improvement in propellant stability is seen upon further addition of the nitroguanidine. Generally it is preferred to add about 10 weight percent of the nitroguanidine to assure inhibition of gas formation due to the aforegoing reaction of the HNF.
Nitroguanidine has been previously added to various solid propellant compositions mainly to serve as a means to control the burning rate of the propellant. In the herein compositions, the nitroguanidine however performs unexpected results, since other similar materials which have been tried do not affect the reaction of HNF with the binder at all or to a minor degree as compared to the nitroguanidine. For example, two nitrocellulose stabilizers, ethyl contralite and 2-nitrodiphenylamine, when added to the composition herein in fact increased the rate of deterioration of the HNF containing propellants. Another material that had been added was resorcinol, which in some tests appeared to slightly increase the shelf life but was not nearly as effective as the nitroguanidine. Various other materials that had also been tested had no effect, or in fact accelerated the deterioration. Thus, unexpectedly nitroguanidine inhibited the reaction of the HNF with the binder to provide a useful propellant composition.
The nitroguanidine is obtained in a powder form and can be added at any time during the mixing of the propellant ingredients. In the mixing of the propellant, normally the binder and plasticizer are first mixed with the fuel then the oxidizer is added thereto. The nitroguanidine is often added with the fuel.
It is believed the invention will be further understood from the following detailed examples.
EXAMPLE 1 A propellant formulation was made by mixing in weight percent l0.92 percent of carboxy terminated polybutadiene, 0.34 weight percent triethylene melamine, 4.74 percent Conoco l-l-35, which is a hydrocarbon oil with a low viscosity, 16 percent aluminum powder, and 68 percent HNF. The carboxy terminated polybutadiene, plasticizer and aluminum fuel were mixed for five minutes in a Baker-Perkins vertical mixer. The HNF was added thereto in three increments, mixing for 10 minutes after each addition. Finally, the curing agent was added and mixing was continued for 10 minutes in vacuum to obtain a void-free mix. This propellant cured in about 24 hours at ambient temperature. Swelling and porosity of the propellant mixture became evident after 6 days at ambient temperature.
EXAMPLE ll A composition containing 13.9 weight percent carboxyl terminated polybutadiene, 0.6 weight percent triethylene melamine, 3.5 weight percent Conoco H-35, l percent aluminum powder and 62 percent HNF was formulated as described in Example I. To this composition during the mixing thereof was added 10 percent nitroguanidine. The propellant was cast into plastic containers which had a length to diameter ratio of 3. The propellant cured in about 24 hours at ambient temperature then was stored at ambient temperature and was examined frequently.
The above formulation of this example showed no deterioration such as swelling or softening after 5 months storage at ambient temperatures.
EXAMPLE [I] To indicate that nitroguanidine appeared to particularly achieve the unexpected results of the herein invention a related compound, cyanoguanidine, was utilized as an additive to the propellant formulation. A composition was thus formulated containing 12.4 percent carboxy terminated polybutadiene, 0.5 percent triethylene melamine, 3.1 percent Conoco H-25, 10 percent aluminum powder, 68 percent HNF, and 6 percent cyanoguanidine. The resulting cured composition began swelling 13 days after mixing at ambient temperature.
Thus, as can be seen from the examples and above description, nitroguanidine unexpectedly and peculiarly serves to inhibit a reaction between HNF and unsaturated hydrocarbon binders, particularly carboxyl terminated polybutadiene. No theoretical explanation for the effect of nitroguanidine has been developed. The possibility that the stabilizing effect might be due to the nitramino group (--NHNO was considered. Ethylene dinitramine, containing two of these groups. however, was not effective.
Iclaim:
l. A solid propellant composition comprising:
an unsaturated carboxyl terminated polymeric hydrocarbon binder,
hydrazinium nitroformate is an amount sufficient to act as an oxidizer,
a suitable curing agent for said binder,
and nitroguanidine as an amount sufficient to improve the shelf life of the composition.
2. The composition of claim 1 wherein said binder is carboxyl terminated polybutadiene.
3. The composition of claim 1 wherein said curing agent is triethylene melamine.
4. The composition of claim 1 further comprising:
a solid particulate metal fuel.
5. A solid propellant corn osition co'm rising:
5 to 25 weight percent of unsaturate carboxyl terminated polymeric hydrocarbon binder,
50 to 65 weight percent hydrazinium nitroformate,
0.2 to 1.0 weight percent ofa curing agent for said binder,
and 2 to 20 weight percent nitroguanidine.
6. The composition of claim 5 further comprising:
5 to 20 weight percent ofa solid particulate metal fuel.
7. The composition of claim 6 wherein said binder is carboxyl terminated polybutadiene.
8. The composition of claim 7 wherein said curing agent is triethylene melamine.
9. The composition of claim 5 additionally comprising:
up to 20 weight percent of a suitable plasticizer for said binder.
Claims (8)
- 2. The composition of claim 1 wherein said binder is carboxyl terminated polybutadiene.
- 3. The composition of claim 1 wherein said curing agent is triethylene melamine.
- 4. The composition of claim 1 further comprising: a solid particulate metal fuel.
- 5. A solid propellant composition comprising: 5 to 25 weight percent of unsaturated carboxyl terminated polymeric hydrocarbon binder, 50 to 65 weight percent hydrazinium nitroformate, 0.2 to 1.0 weight percent of a curing agent for said binder, and 2 to 20 weight percent nitroguanidine.
- 6. The composition of claim 5 further comprising: 5 to 20 weight percent of a solid particulate metal fuel.
- 7. The composition of claim 6 wherein said binder is carboxyl terminated polybutadiene.
- 8. The composition of claim 7 wherein said curing agent is triethylene melamine.
- 9. The composition of claim 5 additionally comprising: up to 20 weight percent of a suitable plasticizer for said binder.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US7486170A | 1970-09-23 | 1970-09-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3658608A true US3658608A (en) | 1972-04-25 |
Family
ID=22122106
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US74861A Expired - Lifetime US3658608A (en) | 1970-09-23 | 1970-09-23 | Hydrazinium nitroformate propellant stabilized with nitroguanidine |
Country Status (1)
Country | Link |
---|---|
US (1) | US3658608A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0520104A1 (en) * | 1991-06-27 | 1992-12-30 | Thiokol Corporation | Non-self-deflagrating fuel compositions for high regression rate hybrid rocket motor application |
US5520756A (en) * | 1990-12-11 | 1996-05-28 | Hercules Incorporated | Stable plasticizers for nitrocellulose nitroguanidine-type compositions |
US5837930A (en) * | 1991-07-04 | 1998-11-17 | Agence Spatiale Europeene | Propellants, in particular for the propulsion of vehicles such as rockets, and process for their preparation |
EP0959058A1 (en) * | 1998-05-20 | 1999-11-24 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | Hydrazinium nitroformate based high performance solid propellants |
US6572717B1 (en) * | 1998-05-13 | 2003-06-03 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | Hydrazinium nitroformate |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3046829A (en) * | 1959-06-22 | 1962-07-31 | Olin Mathieson | Composite propellent grains |
US3147161A (en) * | 1961-06-19 | 1964-09-01 | Minnesota Mining & Mfg | Propellant composition cured with aziridinyl compounds |
US3305523A (en) * | 1962-08-30 | 1967-02-21 | North American Aviation Inc | Modification of telechelic-type polymers |
US3418183A (en) * | 1963-12-04 | 1968-12-24 | Thiokol Chemical Corp | Propellant comprising hydrazine nitroform stabilized with dicarboxylic acid anhydride |
US3476622A (en) * | 1966-12-20 | 1969-11-04 | Asahi Chemical Ind | Carboxy-terminated composite rocket propellant and process for producing using an amide additive |
-
1970
- 1970-09-23 US US74861A patent/US3658608A/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3046829A (en) * | 1959-06-22 | 1962-07-31 | Olin Mathieson | Composite propellent grains |
US3147161A (en) * | 1961-06-19 | 1964-09-01 | Minnesota Mining & Mfg | Propellant composition cured with aziridinyl compounds |
US3305523A (en) * | 1962-08-30 | 1967-02-21 | North American Aviation Inc | Modification of telechelic-type polymers |
US3418183A (en) * | 1963-12-04 | 1968-12-24 | Thiokol Chemical Corp | Propellant comprising hydrazine nitroform stabilized with dicarboxylic acid anhydride |
US3476622A (en) * | 1966-12-20 | 1969-11-04 | Asahi Chemical Ind | Carboxy-terminated composite rocket propellant and process for producing using an amide additive |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5520756A (en) * | 1990-12-11 | 1996-05-28 | Hercules Incorporated | Stable plasticizers for nitrocellulose nitroguanidine-type compositions |
EP0520104A1 (en) * | 1991-06-27 | 1992-12-30 | Thiokol Corporation | Non-self-deflagrating fuel compositions for high regression rate hybrid rocket motor application |
US5837930A (en) * | 1991-07-04 | 1998-11-17 | Agence Spatiale Europeene | Propellants, in particular for the propulsion of vehicles such as rockets, and process for their preparation |
US6572717B1 (en) * | 1998-05-13 | 2003-06-03 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | Hydrazinium nitroformate |
EP0959058A1 (en) * | 1998-05-20 | 1999-11-24 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | Hydrazinium nitroformate based high performance solid propellants |
WO1999059940A1 (en) * | 1998-05-20 | 1999-11-25 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappijk Onderzoek Tno | Hydrazinium nitroformate based high performance solid propellants |
US6916388B1 (en) | 1998-05-20 | 2005-07-12 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | Hydrazinium nitroformate based high performance solid propellants |
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