WO1993013051A1

WO1993013051A1 - Energetic polymers and process for preparation thereof

Info

Publication number: WO1993013051A1
Application number: PCT/US1992/010499
Authority: WO
Inventors: Eugene F. Rothgery; Rahim Hani; Richard H. Dumas; Ming Shen
Original assignee: Olin Corporation
Priority date: 1991-12-23
Filing date: 1992-12-07
Publication date: 1993-07-08
Also published as: EP0618893A1; AU3240093A; EP0618893A4; JPH08500325A

Abstract

This invention relates to energetic binders, and, more specifically, a class of nitramine-containing polyether polymers characterized by favorable viscosity and glass transition temperature, as well as resistance to hydrolysis are prepared. The invention also claims a process for producing a polymer containing nitramine- and/or nitro- and/or fluoro-groups which comprises reacting at least one nitramine-containing diacid chloride monomer with at least one nitro- or fluoro-containing diol monomer in an anhydrous organic solvent (preferably tetrahydrofuran (THF), acetonitrile, or diethylether, although other organic solvents can be employed such as pentane, hexane, heptane, methylene chloride, dichloroethane, toluene, benzene, and the like) in the presence of a tertiary amine base at a reaction temperature of between about 0 °C and about 50 °C.

Description

ENERGETIC POLYMERS AND PROCESS

FOR PREPARATION THEREOF

This invention relates generally to energetic binders, and, more specifically, to a class of

nitramine-containing polymers characterized by enhanced energy, as well as favorable viscosity, glass transition temperature, and resistance to hydrolysis.

The demand by the military community for low

signature propellents has resulted in the change from ammonium perchlorate to ammonium nitrate as the oxidizer of choice in the production of tactical rocket motors. Unfortunately, however, this change has resulted in a reduction in the performance of the rockets, as measured by the specific impulse (I_sp) of the rocket motors.

Various nitropolymers have been fabricated in the past for application in solid, smokeless propellants. For example. Aerojet General published a report. No 1162, dated September 28, 1956, entitled "Research in Nitropolymers and Their Application to Solid Smokeless Propellarts". This report documents various

polymerization reactions useful in making nitropolymers, varicas of nitramino diacils polymers, however, generally have a higher molecular weight than might be desired and do not possess

carefully controlled, reactive, functional end groups as would be desirable.

Hercules Incorporated investigated a specific nitramine-containing polymer, poly(diethylene

glycol-4,7- nitrazadecanedioate) designated as P-DEND. In a report entitled "High Performance Minimum Smoke Propellants", Technical Report CR-RD-PR-86-4, dated May, 1986. Hercules documents work performed for the U.S. Army Missile Command wherein P-DEND is described as being a feasible ingredient for use in nitrate

ester-plasticide propellants. This report states that attempts to fabricate P-DEND by an acid catalyzed esterification reaction of 4,7-dinitrazadecanedioic acid (DNDA) with diethylene glycol in a variety of organic solvents were unsuccessful. This failure is attributed in the report to the fact that a cyclization reaction rather than a polymerization reaction occurred. More recently, it has been found that P-DEND has a viscosity and a glass transition temperature that are higher than might be desired.

There is a need by the military community for high energy binders which are safer and less expensive to manufacture and still afford a good combination of high impetus, low glass transition temperature, and low viscosity. One such way is to prepare energetic poly esters by condensing monomers of energetic diacids or diesters with monomers of energetic or non-energetic diols in hot melt polymerization or solution

polymerization conditions. By way of illustration, U.S. Patent 4,916,206 discloses the reaction of an energetic diacid monomer with a monomeric diol in the presence of in id catalyst using hot polymerization

Unfortunately, hot melt polymerization in general

requires the use of monomers which are heat stable and acid catalyst stable. Consequently, the hot melt

polymerization process sometimes does not lend itself to the use of monomers possessing good energy

characteristics since these monomers are generally

unstable under the required reaction conditions. Another form of polymerization which is

generally known in the art is solution polymerization. Unfortunately, solution polymerization processes typically provide resulting polymers which do not have as high a molecular weight as might be desired.

U.S. Patent 3,808,276 discloses polyether polymer binders for propellant compositions prepared by reacting 1,6-dichloro-2,5-dinitrahexane (DCDNH) with a polyhydroxy alcohol, such as ethylene glycol. No polyester polymer binders are disclosed in this patent.

New polymer binders exhibiting enhanced energy during use and characterized by an advantageous

viscosity and glass transition temperature, as well as a resistance to hydrolysis, would be highly desirable to the propellants and explosives community.

In one aspect, the present invention relates to a nitramine-containing polymer prepared by reacting a nitramine-containing diol with a nitramine-containing diacid or a nitramine-containing, dihalogen-containing compound. The resulting polymer is characterized by high energy as measured by a high specific impulse.

In another aspect, the present invention relates to a nitramine-containing polymer characterized by an advantageous combination of a low viscosity and a low glass transition temperature, as well as resistance to hydrolysis, represented by the Following e*> ;*iri»

structural formula:

wherein a and e have a value 0 or 1, b and d have values of 1 to 3 (preferably 1 or 2), a has a value of 2 or 3, f has a value of 0 to 3 (preferably 0 and 1), x has a value of 1, y has a value of from .10 to 1, and z has a value of from 0 to 0.9, with the proviso that the sum of y plus z is equal to 1, and wherein R is a linear or branched chain alkylene or alkylene ether radical having between 2 and 12 carbon atoms and having primary or secondary carbon atoms at points of attachment of said radical in said polymer, and n has a value between 2 and 50.

In another aspect, the present invention relates to a process for producing a nitramine-containing polymer which comprises the steps of reacting a

nitramine-containing diol with a nitramine-containing diacid or a nitramine-containing, dihalogen-containing compound in the presence of an acid catalyst by a melt polymerization reaction to form said nitramine- containing polymer while removing by-product water during the course of said reaction.

In yet another aspect, the present invention relates to a process for producing a nitramine- containing diol which comprises the steps of:

(a) nitrating an amino alcohol to provide a nitraminoalkylnitrate ester,

(b) acetylating said nitraminoalkylnitrate ester to provide an acetylated ester, and (c) hydrolyzing said acetylated ester with a strong acid in an organic solvent to yield a nitramino alcohol.

In another aspect, the present invention relates to novel nitramine- plus nitro- and/or fluoro-containing polymers characterized by an advantageous combination of high energy, low viscosity, and low glass transition temperature made by a solution polymerization reaction of a nitramine-containing diacid chloride with a nitro- or fluoro-containing diol. These polymers have a weight average molecular weight of between about 1,500 and about 5,000, and are characterized by the following empirical structural formula:

-(OCCH₂CH₂-R¹-CH₂CH₂COO-R²-O)_x-(OCCH₂CH₂

-R³-CH₂CH₂COO-R⁴-O)_y wherein x and y are independently 0 or integers of from 1 to 100, and the sum of x plus y is at least 1;

R ¹ and R³ are independently selected from the following formula: -N(NO₂)(CH₂)zN(NO₂)- wherein z is an integer from 1 to 6 and R²,

R⁴ is independently selected from the following

formula:

-CH₂C(F)₁(NO₂)_mCH₂-,

-CH₂N(NO₂)(CH₂)_nN(NO₂)CH₂-,

-CH₂C(NO₂)₂(CH₂)_oC(NO₂)₂CH₂-,

wherein l and m are independently o or integers and l + m = 2; n is an integer from 1 to 6; o is an integer from 1 to 8.

In still another aspect, the present invention relates to a process for producing a polymer containing detramine- and/or nitro- and/or fluoro-groups which comprises reacting at least one nitramine-containing diacid chloride monomer with at least one nitro- or fluoro- containing diol monomer in an anhydrous organic solvent (preferably tetrahydrofuran (THF), acetonitrile, or diethylether, although other organic solvents can be employed such as pentane, hexane, heptane, methylene chloride, dichloroethane, toluene, benzene, and the like) in the presence of a tertiary amine base at a reaction temperature of between about 0°C and about 50°C (preferably between about 20°C and about 40°C).

These and other aspects will become apparent upon reading the following detailed description of the invention.

Regarding the melt polymerization process of the present invention, after the reaction has begun and particularly during the later stage of the reaction, it is preferred that hydrogen chloride be removed by vacuum as the reaction progresses in order to expedite

formation of the desired nitramine-containing polymer product. Another possibility for the removal of the by-product hydrogen chloride is the addition of an acid acceptor which is non-reactive with the bischloromethyl monomer in the reaction mixture. In addition, it is preferred that the polymer product be purified in a purification step, suitably by precipitation in a solvent/non-solvent mixture or by using gel permeation chromatography. If desired, the nitramine-containing polymer is end-capped with a functional moiety to impart a desired terminal functionality to the polymer. In the absence of such end-capping, the polymer is generally chloro- or hydroxyl-terminated.

Certain polymers described in this invention are of the class described by the general empirical formula given below

wherein a and e have a value 0 or 1, b and d have values of 1 to 3 (preferably 1 or 2), c has a value of 2 or 3, f has a value of 0 to 3 (preferably 0 and 1), x has a value of 1, y has a value of from .10 to 1, and z has a value of from 0 to 0.9, with the proviso that the sum of y plus z is equal to 1, and wherein R is a linear or branched chain alkylene or alkylene ether radical having between 2 and 12 carbon atoms and having primary or secondary carbon atoms at points of attachment of said radical in said polymer, and n has a value between 2 and 50.

The polyether polymers are suitably prepared by reacting a nitramine-containing bischloromethyl monomer with a diol under melt polymerization reaction

conditions (i.e. in the absence of a solvent). Table I summarizes the polymers that were prepared based on the above polymerization method.

Monomers useful in the present invention include the following bischloromethyl derivatives:

2,5-dinitraza-1,6- dichlorohexane;

2,5,8-trinitraza-1,9-dichlorononane; 2,4,6- trinitraza-1,7-dichloroheptane, and 2,6-dinitraza-1,7- dichloroheptane and other bischloromethyl derivatives of similar structure.

Useful nitramine-containing diols include the following: 3-nitraza-1,5-pentanediol and

3,6-dinitraza-1,8-octanediol.

Useful diol monomers include a wide variety of diols, such as, for example, ethylene glycol, propylene glycol, 1,4- butanediol, 1,6-hexanediol, diethylene glycol and various other diols of similar structure.

The polymers identified in Table I above as Polymer 1-8 are preferred due to their relatively low glass transition temperature which provides superior process ability into formulated products, such as propellants or explosives. In addition, these polymers were found to have relatively low viscosity which gives superior performance during processing of the formulated propellent or explosive product.

The polymers and co-polymers of the present invention combine the advantages cited above with high calculated (by the Naval Weapons Center PEP method) impetus in propellent formulations, a desired

functionality of very near two, primarily hydroxyl termination (if desired) of the polymer chains, and a molecular weight which can readily be controlled to many desired values over a wide range. The preferred polymer moleculer weight is between about 590 and about 10,000, more preferably between about 1,500 and about 5,000.

These molecular weights are weight average molecular weights as measured by gel permeation chromatography (GPC) using a polystyrene standard.

Note that the molecular weight of the polymers can be controlled by varying the stoichiometry of the diol and bischloromethyl monomers. Generally, the molar ratio of diol to bischloromethyl monomer ranges between about 1:0.5 and about 0.5:1. Typically, the polymers are prepared using an excess of the diol monomer relative to the bischloromethyl monomer, thereby providing a hydroxy-terminated polymer, preferably a molar ratio of diol to bischloromethyl monomer of between about 1:0.99 and about 1:0.6. If desired, the polymer may be terminated by chloride groups by the simple technique of adjusting the stoichiometric ratio of monomers such that the bischloromethyl (i.e. the bischloromethyl monomer) is present in excess relative to the diol monomer. As another alternative, other functional moieties can be used to end-cap the polymer molecules to impart a desired terminal functionality to the polymer. For example, the hydroxy-terminated polymer can be reacted with an excess of diisocyanate to yield an isocyanate-terrainated polymer. Alternately, a diacid chloride such as adipoyl chloride, phosgene, or other similar compounds can be reacted with the

hydroxy-terminated polymer to give polymers terminated with acid chloride or chloroformate groups. In similar ways, the chloride end groups of the chloride-terminated polymer can be chemically modified to yield any of a variety of functional groups as terminal groups for these polymers. This flexibility in designing the end group or terminal group on the polymer molecule is important because it allows a great range of

possibilities in terms of the curing of these materials with other components to fabricate the desired final product, namely the propellant or explosive product.

The reaction time useful for the melt

polymerization process of the present invention is not narrowly critical and can vary over a wide range. It is preferred that the reaction time be between about 2 and about 8 hours, more preferably between about 3 and about 5 hours. Likewise, the reaction temperature is not narrowly critical and can vary over a wide range.

Preferably the reaction temperature is between about 0°C and about 120°C, more preferably between about 25°C and about 95°, and most preferably between about 45°C and about 65°C, desireably using a melt polymerization.

The melt polymerization reaction in accordance with the present invention is preferably suitably conducted, for the most part, at subatmospheric

pressure, most preferably at a pressure of between about 0.001 mm of Hg and about 600 mm of Hg. The

subatmospheric pressure makes it possible for easy removal of the hydrogen chloride by-product from the reaction mixture, thereby driving the polycondensation reaction to completion as desired. Because of the volatility of some of the monomers employed, however, subatmospheric pressure is preferably not applied during the initial stage of the reaction. Alternative or additional methods can be used to remove by-product hydrogen chloride from the reaction mixture, such as bases which do not react with the bischloromethyl

monomer.

The optional polymer purification step, if utilized, is preferably conducted by precipitation in a mixture of a paired solvent/non-solvent. Suitable solvent/non-solvent pairs can be chosen from the

following solvents: methylene chloride, chloroform, tetrahydrofuran, or any other organic solvent capable of dissolving the polymers; and the following non-solvents: methanol, ethanol, water, hexane, cyclohexane, benzene or any other organic medium which is not a solvent for polymers. Alternately, other purification methods can be employed such as gel permeation chromatography. The polymers produced in accordance with the process of the present invention generally have a weight average molecular weight of between about 500 and about 10,000, preferably between about 1000 and about 5000. The glass transition temperature of the polymer (T_g) is generally less than 0°C, preferably less than -10°C, and more preferably less than -15°C. The viscosity of the polymer is generally less than 50,000 centipoise, preferably less than 20,000 centipoise, and more

preferably less than 10,000 centipoise.

The solution polymerization process used in the present invention is carried out under mild reaction conditions by reacting an energetic diacid chloride monomer with an energetic diol monomer which are

unstable and starts decomposing under the (hot) melt polymerization condition. The concentration of each monomer reactant in the solvent generally ranges between 0.05 and about 1 molar concentration (M.). The molar ratio of diacid chloride monomer relative to the diol monomer is generally between about 0.8:1.2 and about 1.2:0.8. The amine base acts as a catalyst for the polymerization reaction as well as an acid scavenger for HCl released during the reaction. The amount of amine base employed in the process of this invention generally ranges between 0.5 to 2.5 molar equivalents per mole of diacid chloride monomer. The amine base rve as both a catalyst and an acid scavenger in order to facilitate completion of the polymerization reaction. After the reaction is completed, the by-products, hydrochloride amine salt and free hydrochloride, are removed by means of aqueous and brine washes. The polymer is either recovered from the solution by stripping off the solvent or isolated as a precipitate by decanting the solvent. If desired, the polymers could be purified in a purification step, suitably by precipitation in a solvent/non-solvent mixture or by using gel-permeation chromatography. The polymers thus prepared are either acid or a hydroxyl terminated, depending upon whether an excess of the diacid chloride or the diol is employed in the polymerization reaction.

If desired, the terminal acid groups can be further extended or modified, typically before the aqueous work-up, as an acid chloride, with another nucleophile such as a diol, an alcohol, an amine, a thiol and a water molecule. The terminal hydroxyl groups could also be further extended, before the aqueous work-up, with another electrophile such as a diacid chloride, an acid chloride, an isocyanate, an

diisocyanate, an acid, a diacid, an ester, a diester, and an active organic halide. The diol monomers suitably employed in this invention include 2-fluoro-2-nitro-1, 3-propane-diol, 2,2-dinitro-1,3-propane-diol, 2,5- dinitraza-1,6-hexanediol and 2,2,5,5-tetranitro-1,

6-hexanediol. One significant advantage of the ability to incorporate fluoro-containing monomers, such as

2-fluoro-2-nitro-1,3-propane-diol or

2,2-dinitro-1,3-propane-diol, into the energetic

polymers in accordance with the process of the present invention is that the resulting polymers exhibit

enhanced energy (impetus) as compared to conventional energeetic binders. 2,5-Dinitraza-1,6-hexanediol is one of the nitramine diols with very good energy, but

unfortunately it is subject to thermal degradation using melt processing, and therefore the process of the

present invention is particularly useful since thermal degradation of the monomers does not occur during

processing. Thus, the ability to incorporate

2,5-dinitraza-1,6-hexanediol in poly esters in our new process provides polyesters having higher energy than those prepared from 3,6-dinitraza-1,8- octanediol and 3-nitraza-1,5-pentanediol. Preferred diacid chlorides include 4,7-dinitrazadecanoic-1,10-diacid chloride and 4,8- dinitrazaundecanoic-1,11-diacid chloride which are prepared readily from their diacid precursors and thionyl chloride.

Also disclosed is a process of preparing the nitramine-, nitro-, and fluoro-containing polyesters under a mild anhydrous condition, generally at ambient temperature, in an nonprotonic solvent and the presence of a amine base. The amine base is necessary to add to the reaction in order to achieve desirable molecular weights, 1,000 to 5,000. Without the amine base, we found in our investigation, only low molecular weight polymers, <1,000, were obtained. We are also able to control the molecular weights of the polymers by

appropriately adjusting the equivalents of amine base : in general, the higher equivalent of the amine base, the higher molecular weight of the polymer. An analogous study, reported in a 1987 annual progress report for SYNTHESIS OF ENERGETIC SINGLE PHASE AND MULTI-PHASE POLYMERS by the RESEARH AND TECHNOLOGY DEPARTMENT OF NAVAL SURFACE WAREFARE CENTER, disclosed a synthesis of energetic poly esters using various diόls and diacid chlorides such as 4,4-dinitropimeloyl chloride and malonyl chloride. However, in addition to their

findings that the polymers were either too unreactive for block linking or significant chain extension, or poor in reproducibility, the polymer synthesis was conducted at elevated temperature, normally at 85-100°C, which is unnecessary in our process when an amine base is used. The polymers prepared by solution polymerization in accordance with this invention are any of a variety described by the general empirical formula given above. The polymers are prepared by reacting at least one nitramine-containing diacid chloride monomer with at least one nitramine- and/or nitro- and/or fluoro- and/or other energetic and non- energetic-containing diol monomer in an anhydrous solvent. The addition of an appropriate amount, for example 0.5-2.5 equivalents, of an amine base serves as both a catalyst and an acid scavenger to complete the reaction. After the reaction is over, the by-products, hydrochloride amine salt and free hydrochloride, are suitably removed by repeatedly aqueous and brine washes. The polymer is either

recovered from the solution by stripping off the solvent or isolated as a precipitate by decanting the solvent. If desirable, the polymers could be purified in a

purification step, suitably by precipitation in a

solvent/non-solvent mixture or by using gel-permeation chromatography.

The monomers useful in making the novel polymers of the present invention have been described above. As described above, the diol monomers are generally nitro- or fluoro-containing monomers, although, if desired, nitramine-containing diol monomers are suitably employed as the diol monomer in the process of the present

invention, and the process is particularly useful in polymerizing monomers whose decomposition temperature is at (or below) the melting point of the monomer, such as 2,5-dinitraza-1,6-hexanediol, since melt polymerization methodology would not be suitable for processing such degradable monomers.

In the solution polymerization process of the present invention, the sequence of addition is not critical. In general, the diacid chloride monomer, the diol monomer, and the amine base can be added neat or in solution either simultaneously or sequentially. One exception is with 2,5-dinitraza-1,6-hexanediol which is incompatible with amine base and monodehydroxylated in the presence of amine base, and amine base must be added after the additions of the diacid chloride and the diol monomers are completed. The concentration of the diacid chloride is generally between about 0.05 to about 1 molar, preferably between about 0.1 to about 0.8 molar, and more preferred between about 0.2 to 0.4 molar. The molar equivalents of the diol is generally between about 0.8 to about 1.2, preferably between about 0.9 to about 1.1, and more preferably between about 0.95 to about 1.05. The molar equivalents of the amine base is generally between about 0.5 to about 2.5, preferably between about 1 to about 2, and more preferrably between about 1.3 to about 1.7. The preferable reaction time is between about 10 min. to about 24 hrs., more preferably between about 1 to about 20 hrs., and most preferably between about 3 to about 18 hrs. The preferable

reaction temperature is between about 0 to about 50°C, more preferably between about 10 to about 40°C, and most preferably between about 20 to about 30°C. Useful amine bases include aromatic amines such as pyridine and lutidine, aliphatic 3° amines such as triethyl amine, tributyl amine, and amines with similar structure.

Useful solvents include anhydrous nonprotonic solvents, such as, for example, tetrahydrofuran (THF),

acetonitrile, diethyl ether, pentane, hexane, heptane, methylene chloride, chloroform, dichloroethane, toluene, benzene, N,N-dimethylformamide and solvents with similar structure. The polymers prepared in accordance with the solution polymerization of the present invention have a weight average molecular weight by gpc between about 1,000 to about 5,000, a glass transition temperature (Tg) between about -30 to about 10°C, in general < 0°C, and a decomposition temperature (Td) between about 200 to about 250°C.

As used herein, the term "percent" designates weight percent and the term "fraction" designates mole fraction unless otherwise specified.

The aforementioned technical publications are incorporated herein by reference in their entirety.

The following examples are intended to illustrate, but in no way limit the scope of, the present invention.

The preparations in Examples 1 and 2 are of the requisite diacid and dichloro compounds needed in preparing the polyesters and polyethers respectively and are given for reference. A. EXAMPLES OF MONOMER SYNTHESIS

Example 1

Preparation of 1 , 6-Dichloro-2 , 5-dinitrazahexane

Sulfuric acid (108 ml) was charged to a 1L beaker equipped with mechanical stirrer and cooled to 15°C. Nitric acid (948.5 ml, 70%) was added dropwise at 15°C. 2-Imidazolidone (17.93, 96%, 0.20 mole) was added in small portions at 15°C, then the reaction mixture was held for 75 minutes at 15°C. The reaction was quenched with 800 ml of ice water to give the intermediate product (A) which was filtered and washed with 180 ml of ice water.

The intermediate product (A) was mixed with 900 ml of hot (50-60°C) water in a covered beaker and heated to boiling while stirring for 20 minutes. The solution was cooled, with slow stirring, to 15°C for 15 minutes, the product filtered off, washed with 100 ml of

ice water and dried under vacuum at room temperature. Ethylenedinitramine, EDNA (21 g), (B) was produced in a 69.9% yield. The EDNA (21 g), 1,3,5-trioxane (21 g) and acetic acid (71 ml) were charged to a stirred 200 ml flask. Anhydrous HCl was bubbled at 50-55° in via a dip tube for 1.5 hours. The reactor was then cooled to 15°C for 30 minutes, the product filtered off, washed with 60 ml fresh acetic acid, recrystallized with 265 ml of chloroform and dried to give 34.57 g of 1,6,dichloro- 2,5-dinitrazahexane (C) (mp 108-109°C) for a 59.1% yield in this step. The overall yield was 41.3% for the entire reaction scheme. Example 2 Preparation of 4 , 8-Dinitrazaundeconic-1 , 11-diacid

H₂NCH₂CH₂CH₂NH₂ + 2 CH₂CHCN --->

(A) NCCH₂CH₂NHCH₂CH₂CH₂NHCH₂CH₂CN + 2 HNO₃ ---> -HNO₃ -HNO₃

(B) NCCH₂CH₂NHCH₂CH₂CH₂N HCH₂CH₂CH ---->

NO₂ NO₂ HCl

(C) NCCH₂CH₂NCH₂CH₂CH₂NCH₂CH₂CH ----> (D) HOCCH₂CH₂NCH₂CH₂CH₂NCH₂CH₂COH

1,3-Diaminopropane (8.30 g, 0.1120 mole) and 170 ml of methanol were charged to a stirred 300 ml 3-neck flask with reflux condenser and under a nitrogen cover.

Acrylonitrile (12.5 ml) was added dropwise while keeping the temperature below 45°C. After the addition was completed,the reaction mixture was stirred for 30 minutes at 45°C, then heated to reflux for another 30 minutes. The reactor was cooled to 10°C and a solution of 70% HN0₃ (22.4 ml) and water (11.2 ml) added and the reactor cooled to 5°C for 1 hour. The product was filtered, washed with 40 ml of cold methanol and dried under vacuum at room temperature to give 22.0 g of (B), a 64% yield.

Acetic anhydride (94 ml) was charged to a stirred 300 ml 3- neck flask under N₂. The reactor was cooled to 10°C, 98% HN0₃ (1.7 ml) and 37% HCl (1.1 ml) were added. 19.9 g of (B) was added in small portions over a period of 4 hour at 30-35°C. Extra portions of HCl, totaling 54 ml were added dropwise as needed to keep the reaction mixture a dark yellow color. After the addition was complete the reaction mixture was held for 30 minutes at 35°C, then warmed to 50-55°C for another 30 minutes. The reactor was cooled to 10°C and 120 ml of ice/water added. The product was removed by filtration, washed with 100 ml of cold water and allowed to dry for about 15 minutes on the filter.

All of the damp (C) cake and 37% HCl (160 ml) were charged to a stirred 300 ml flask equipped with are flux condenser and heated to reflux for 16 hours. 20 ml of water was distilled of under vacuum, then the

reaction mixture was cooled to 5°C for 30 minutes. The product was filtered off, washed with 50 ml of cold water and dried under vacuum at room temperature to give 10.0g. of (D) for a 50% yield.

The overall yield of 4,8-dinitrazaundecanoic-1, 11-diacid was 32.0% based on the 1,3-diaminopropane.

The melting point of the diacid obtained was 144-146°C.

Example 3

Preparation of 3-Nitraza-1,5-pentanediol HOCH₂CH₂NHCH₂CH₂OH + 3HNO₃ --->

·HNO₃

(A) NO₂OCH₂CH₂NHCH₂CH₂ONO₂ + CH₃COCl --->

NO₂ O

(B) NO₂OCH₂CH₂NCH₂CH₂ONO₂ + 2CH₃CONa --->

O NO₂ O HCl

(C) CH₃COCH₂CH₂NCH₂CH₂OCCH₃ --->

NO₂

(D) HOCH₂CH₂HCH₂CH₂OH

Eight ml of 98% HNO. were charged to a stirred 50 ml 3- neck flask under N₂ and cooled to 7-8°C. Diethanolamine (6 g, 0.0571 mole) was added portion wise and the resulting mixture stirred for 1 hour at 15°C, and for 30 minutes at 23°C. Acetic anhydride (0.2 g) was added and the reaction mixture stirred for 15 minutes.

Acetic anhydride (19.0 g) and acetyl chloride (0.2 g) were charged to a stirred 50 ml, 3-neck flask under N₂. At 35°C the nitration mixture (A) was added dropwise at 35°C, and held at that temperature for 2 hours. The reaction mixture was then poured into 135 ml of stirred ice-water. The precipitated product was filtered off, washed with 10 ml of ice water and then dissolved in 21 ml of acetone. The pH was adjusted to 7.0 with 0.5M Na₂CO₃ and the solution poured into

120 ml of stirred ice- water. The mixture was allowed to stand in a refrigerator for 3 hours, the product

filtered off and washed with 50 ml of ice water.

The damp nitrate ester (B), glacial acetic acid (76 ml) and sodium acetate (13.91 g) were charged to a stirred 100 ml flask and held at reflux (125°C) for 16 hours. The reaction mixture was stripped to dryness, 35 ml of methylene chloride and 35 ml of water added and stirred to obtain a complete solution. The mixture was phase separated, the organics washed with 10 ml of water and stripped to dryness, leaving 9.92 g of 3-nitraza- 1,5-pentanediacetate (C) for a 74.2% yield.

The diacetate (C), methanol (110 ml) and HCl (35 ml, 37%) were charged to a 250 ml flask and heated to reflux for 16 hrs. The reaction mixture was stripped to dryness leaving 6.44 g of diol (D) (95% by L.C.

analysis) for a 71.4% yield overall based on the

starting diethanolamine. Ex ample 4 Preparation of 3,6-Dinitraza-1,8-octanediol

HOCH₂CH₂NHCH₂CH₂NHCH₂CH₂OH + 4 HNO₃ --->

·HNO₃ ·HNO₃ HNO₃

(A) NO₂OCH₂CH₂NHCH₂CH₂NHCH₂CH₂ONO₂ --->

HCl

NO₂ NO₂ O

(B) NO₂OCH₂CH₂NCH₂CH₂NCH₂CH₂ONO₂ + 2CH₃CONa --->

HCl

(C) CH₃ COCH₂CH₂NCH₂CH₂NCH₂CH₂OCCH₃ --->

NO₂ NO₂

(D) HOCH₂CH₂ NCH₂CH₂HCH₂CH₂OH

Nitric acid (120 ml 98%) was charged to a stirred 200 ml, 3-neck flask under N₂ and cooled to 5°C. N,N'-Bis(2- hydroxyethyl)ethylenedi amine (25.64 g, 0.20 mole) was added in small portions over a 1.75 hours at 5°C. Stirring was continued for 30 minutes at 5°C after completing the addition, then for another hour at 23°C. The reaction mixture was poured into 350 ml of stirred ice-water, the product filtered off, washed with 200 ml of ice water and dried under vacuum at 50°C to leave 59.22 g. of product (A) (decomposed at 149°C) for a 81.3% yield.

Acetic anhydride (210 ml) was charged to a stirred 500 ml flask under N₂ and cooled to 10°C.

HNO₃ (3.72 m., 98%) and HCl (2.43 ml, 37%) were

added. Product A (59.22 g, 0.1626 mole) was added in small portions over 3.5 hours at 33°. An additional 6.31 g of 37% HCl was added a few drops at the time as needed to keep the reaction mixture a dark yellow color. After completing the addition, the reaction mixture was held for 30 minutes at 35°C and 30 minutes at 50-55°C. The reactor was cooled to 10°C and its contents poured into 1 liter of stirred ice-water. This mixture was left stirring slowly at 10°C for 30 minutes, the product was filtered off and washed with 175 ml of ice water. The damp filtrate was dissolved in 945 ml of hot chloroform, filtered and allowed to cool. The product was then filtered off, washed with cold

chloroform and dried under high vacuum at room

temperature to leave 34.56g of (B) (mp 59-60°C), a 64.8% yield.

Product B (34.56 g, 0.11 mole), sodium acetate (29 g) and glacial acetic acid (210 ml) were charged to a stirred 300 ml flask and heated to reflux for 16 hours. The reaction mixture was allowed to cool slowly to room temperature and was then chilled to 15°C for 30 minutes. The product was filtered off and washed with 120 ml of acetic acid. The damp product was stirred with 90 ml of cold water for 15 minutes, filtered and dried at 50°C under vacuum to leave 23.36 g of (C) (mp 147-149°C) for a 68.9% yield.

(C) (23.36 g, 0.0725 mole), methanol (290 ml) and HCl (63 ml, 37%) were charged to a stirred 500 ml flask and heated to reflux for 16 hours. The reaction mixture was stripped to dryness under high vacuum

leaving 17.36 g of yellow oil, which was-dissolved in 30 ml of acetone and the solution poured into 350 ml of stirred chloroform. The solution was stirred slowly at 5°C for 20 minutes, the product filtered, washed with fresh chloroform and dried under vacuum at room

temperature leaving 15.80 g of diol (D) (mp 93-94°C) for a 91.4% yield. The overall yield for all four steps was 33.2%. B. EXAMPLES OF POLYMER SYNTHESES

Example 5

Preparation of Energetic Polymer 1 which has the empirical structural formula : NO₂ NO₂ NO₂ NO₂

(CH₂NCH₂CH₂NCH₂OCH₂CH₂NCH₂CH₂NCH₂CH₂O)_n

1,6-Dichloro-2,5-dinitrazahexane (2.4705 g, 0.0100 mole), 3, 6-dinitraza-1,8-octanediol (2.5074 g, 0.0105 mole), and dry tetrahydrofuran (5 ml) were charged to a dried 50 ml, 3- neck flask fitted with an inlet tube and a reflux condenser. A slow N₂ flow was maintained through the solution via the inlet tube in order to remove HCl. The reactor was heated at reflux for hours.

About 1.5 ml per hour of THF was added to make up for evaporative losses. The reaction mixture was cooled to room temperature and then poured dropwise into 100 ml of rapidly stirred methanol. The methanol solubles were decanted off, the polymer washed twice with 25 ml of methanol and dried under high vacuum at 60°C. 3.83 g of polymer was produced for a 93% yield. The polymer had a weight averaged molecular weight of 836, as determined by Gel Permeation Chromatography, a glass transition temperature of -18°C and a

decomposition temperature of 188°C, as determined by Differential Scanning Calorimetry. The estimated heat of formation using the values according to Benson is -49.8 kcal/mole. Examole 6 Preparation of Energetic Polymer 2 which has the empirical structural formula:

O NO₂ NO₂ O NO₂ NO₂

(CCH₂CH₂NCH₂CH₂CH₂NCH₂CH₂COCH₂CH₂NCH₂CH₂NCH₂CH₂O)_n

4,8-Dinitrazaundecanoic-1,11-diacid (3.0826 g, 0.0100 mole), 3,6-dinitraza-1,8-octanediol (2.5074 g, 0.0105 mole), p- toluenesulfonic acid monohydrate

(0.031g) and 1,2-dichloroethane (EDC) (5 ml) were charged to a stirred 50 ml flask fitted with

bottom-return Dean-Stark trap and a reflux condenser. The reactor was heated to reflux with an oil bath for 5.5 hours. Wet EDC was removed as needed and replaced with an equal volume of dry solvent. The EDC was stripped off and the product dissolved in 5 ml of tetrahydrofuran. This solution was poured dropwise into 100 ml of rapidly stirred methanol, the solubles were decanted away, the polymer washed twice with 25 ml of methanol and dried under high vacuum at 60°C. The polymer (4.64g) was recovered for a 91% yield. The weight averaged molecular weight of the polymer was 1158, the T_G was -15°C, and the T_d was 249°C. The estimated heat of formation is -63.3 kcal/mole. Example 7

Preparation of Energetic Polymer 3 which has the empirical structural formula:

NO₂ NO₂ NO₂

(CH₂NCH₂CH₂NCH₂OCH₂CH₂NCH₂CH₂O)_n

1,6-Dichloro-2,5-dinitrazahexane (2.4705g, 0.0100 mole), 3- Nitraza-1,5-pentanediol (1,6637 g, 95%, 0.0105 mole), and dry tetrahydrofuran (5 ml) were charged to a dry, stirred 50 ml, 3- neck flask fitted with an inlet tube and a reflux condenser. A slow N₂ flow was maintained through the solution to remove HCl. The reactor was heated at reflux with an oil bath for 12 hours. About 1.5 ml per hour of THF was added to make up for evaporative losses. The reaction mixture was cooled to room temperature and poured dropwise into 100 ml of rapidly stirring methanol. The solubles were decanted away, the polymer washed twice with 25 ml of methanol and dried under high vacuum at 60°C. Polymer (1.80 g) was obtained, corresponding to a 55.6% yield. The polymer had a weight averaged molecular weight of 611, the T_G was - 35°C and the T_d was 163°C. The estimated heat of formation is -52.5 kcal/mole. Example 8

Preparation of Energetic Polymer 4 which has the empirical structural formula:

O NO₂ NO₂ O NO₂

(CCH₂CH₂NCH₂CH₂CH₂NCH₂CH₂COCH₂CH₂NCH₂CH₂O)_n

4,8-Dinitrazaundecanoic-1,11-diacid (3.0826 g, 0.0100 mole), 3-nitraza-1,5-pentanediol (1.6637 g, mole), 0.0310g. p-toluenesulfonic acid monohydrate (0,031 g) and 1,2-dichloroethane (EDC) (5 ml) were charged to a stirred 50 ml flask with bottom-return Dean-Stark trap and a reflux condenser. The reactor was heated to reflux with an oil bath for 5.5 hours. Wet EDC was removed as needed and replaced with an equal volume of dry solvent. The EDC was stripped off and the product dissolved in 5 ml of tetrahydrofuran. The solution was poured dropwise into 100 ml of rapidly stirred methanol, the solubles were decanted away, the polymer washed twice with 25 ml of methanol and dried under high vacuum at 60°C. 2.95g. of polymer was recovered for a 69.9% yield. The weight averaged molecular weight of the polymer was 1000, the T_G was -20°C and the T_d was

247°C. Examole 9

Preparation of Energetic Polymer 5 which has the empirical structural formula:

NO₂ NO₂ NO₂ NO₂ NO₂

[CH₂NCH₂CH₂NCH₂)_1.0(OCH₂CH₂NCH₂CH₂NCH₂CH₂O)_0.5(OCH₂CH₂N

CH₂CH₂O)_0.5]_n

2.5024g 1,6-dichloro-2,5-dinitrazahexane (0.010 mole, 1.1910g 3,6-dinitraza-1,8-octanediol (0.0050 mole), 1.1711g 3-nitraza-1,5- pentanediol (0.0050 mole) and 5 ml THF (dried over sieves) were charged to a dry, stirred 50 ml flask with inlet tube and reflux

condenser. With a 0.1 SCFH N₂ flow the reactor was heated to reflux via a 70°C oil bath for 6 hrs. 1 ml/hr of make-up THF was added during the heating period. The bath temperature was lowered to 60°C and 5 ml. THF was added to dissolve the polymer. The resulting solution was cooled to room temperature and poured dropwise into 100 ml of rapidly stirring methanol. The methanoo solubles were decanted away from the polymer which was then washed twice with 25 ml of fresh methanol and dried under vacuum at 55°C 2.98 g of polymer was recovered for a 81.0% yield. The weight-average molecular weight of the polymer was 1144, the T_G was -29°C and the T_d was 226°C. Example 10

Preaoaration of Energetic Polymer 6 which has the

empirical structural formula :

NO₂ NO₂ NO₂ NO₂

[(CH₂NCH₂CH₂HCH₂)_1.0(OCH₂CH₂HCH₂CH₂NCH₂CH₂O)_0.5(OCH₂CH₂CH₂O)_0.5]_n

2.5024 g of 1,6-dichloro-2,5-dinitrazahexane (0.010 mole), 1.1910 g of 3,6-dinitraza-1,8-octanediol (0.0050 mole), 0.3805 g of 1,3- propanediol (0.0050 mole) and 5 ml of THF (dried over sieves) were charged to a dry, stirred 50 ml flask with inlet tube and reflux

condenser. With a 0.1 SCFH N₂ flow the reactor was heated to reflux via a 70°C oil bath for 6 hrs. 1 ml/hr of make-up THF was added during the heating period. The bath temperature was lowered to 60°C and 5 ml THF was added to dissolve the polymer. The resulting solution was cooled to room temperature and poured dropwise into 100 ml of rapidly stirring methanol. The methanol

solubles were decanted away from the polymer which was then washed twice with 25 ml of fresh methanol and dried under vacuum at 55°C. 2.64 g of polymer was recovered for a 81.6% yield. The weight-average molecular weight of the polymer was 1214, the T_G was -28°C and the T_D was 228°C. Example 11

Preparation of Energetic Polymer 7 which has the empirical structural formula: O NO₂ NO₂ O NO₂ NO₂

[(CCH₂CH₂NCH₂CH₂CH₂NCH₂CH₂C) _1.0(OCH₂CH₂NCH₂CH₂NCH₂CH₂O)_0.5 (OCH₂CH₂NCH₂CH₂O)_0.5]_n

3.0826 g of 4,8-dinitrazaundecanoic-1,11-diacid (0.010 mole), 1.1910 g of 3, 6-dinitraza-1,8-octanediol (0.0050 mole), 0.7507 g of 3-nitraza-1,5-pentanediol (0.0050 mole), 0.0310 g of p-toluene sulfonic acid monohydrate and 5 ml of 1,2-dichloroethane (EDC) (dried over sieves) were charged to a dry, stirred 25 ml flask with

bottom-return Dean-Stark trap and reflux condenser. The reactor was heated to reflux with a 110°C oil bath for 6 hrs. Wet EDC was removed as needed and replaced with an equal volume of dry solvent. The EDC was stripped off and the product was dissolved in 5 ml tetrahydrofuran. The solution was poured dropwise into 100 ml of rapidly stirring methanol, the methanol solubles were decanted away, the polymer washed two times with 25 ml of

methanol and dried under high vacuum at 60°C 3.82 g of polymer was recovered for a 82% yield. The

weight-average molecular weight of the polymer was 1220, the T_G was 24°C, and the T_D was 250°C. Example 12

Preparation of Energetic Polymer 8 which has the empirical structural formula : O NO₂ NO₂ O NO₂ NO₂

3.4514 g of 4, 8-dinitrazaundecanoic-1, 11-diacid (0.010 mole) , 1.1910 g of 3 , 6-dinitraza-1, 8-octane diol (0.0050 mole) , 0.3805g of 1, 3-proρane diol (0.0050 ml) , 0.0310 g of p-toluene sulfonic acid monohydrate and 5 ml of THF (dried over sieves) were charged to a dry, stirred 25 ml flask and heated to 90°C. After 10 minutes , a vacuum was applied and the reactor was held at 90°C for 4 hours , then was heated to 100°C for 1 hr . The product was dissolved in 5 ml tetrahydrofuran. The solution was poured dropwise into 100 ml of rapidly stirred methanol , the methanol solubles were decanted away, the polymer was washed two times with 25 ml of methanol and dried under high vacuum at 60°C 2.12 g of polymer was

recovered for a 50% yield. The weight-average molecular weight of the polymer was 1043 , the T_G was -26°C, and the T_D was 252°C. Example 13

SYNTHESIS OF A FLUORO- AND NITRO-CONTAINING POLYESTER

POLYMER USING 2-FLUORO-2-NITRO-1,3-PROPANE-DIOL AND

4,8-DINITRAZAUNDECANOIC-1,11-DIACID CHLORIDE MONOMER 4,8-Dinitrazaundecanoic-1,11-diacidchloride (94 mg, 0.27 mmol) and 2-fluoro-2-nitro-1,3-propane-diol (39 mg, 0.28 mmol) were dissolved in dry THF (0.16 ml). A mixture of pyridine (48 ul, 0.59 mmol) and dry THF (0.16 ml) was added dropwise to the stirring solution at ambient temperature. A white precipitate was formed during the addition, and the addition was completed over a period of about 4 min. After the reaction mixture was stirred at ambient temperature for 17 hr., 1 ml of THF and 0.2 ml of water were added. The reaction mixture was stirred for about 5 minutes until the solids were dissolved. The THF layer was separated, washed with 4 x 0.4 ml of brine, dried over anhydrous MgS04, filtered, and stripped off the solvent. 91 mg of a gummy material were recovered. The polymer was determined to have a Tg of 1.31°C, a Td of 238.7°C and a Mw of 3763 by gpc.

Example 14

SYNTHESIS OF A FLUORO- AND NITRO-CONTAINING POLYESTER

POLYMER USING 2-FLUORO-2-NITRO-1,3-PROPANE-DIOL AND 4,8-DINITRAZAUNDECANOIC-1,11-DIACID CHLORIDE MONOMERS 4,8-Dinitrazaundecanoic-1,11-diacid chloride (108 mg, 0.31 mmol) and 2-fluoro-2-nitro-1,3- propane-diol (50 mg, 0.36 mmol) were dissolved in dry THF (1.6 ml) and 51 ul (0.63 mmol) of pyridine was added dropwise at ambient temperature. A white precipitate was formed during the addition of pyridine. After stirring at ambient temperature for about 18 hrs., 0.5 ml of water were added, and the reaction mixture was stirred for another 2 hrs. The THF layer was separated, washed with 4 x 0.4 ml of brine, dried over with anhydrous MgS04, filtered, and stripped off the solvent. 70 mg of a viscous polymer were obtained. The polymer has a Tg of -6°C, a Td of 235°C, and a Mw of 2419 by GPC.

Example 15

SYNTHESIS OF A FLUORO- AND NITRO-CONTAPOLY ESTER USING 2-FLUORO-2- NITRO-1PROPANE-DIOL AND 4, 8-DI-NITRAZAUNDECANOIC-1,11-DIACID CHLORIDE

Example 2 was repeated except the pyridine use level was reduced from about 2 equivalents (51 ul, 0.63 mmol) to about 1.5 equivalents (38 ul, 0.47 mmol). 136 mg of a clear viscous polymer were obtained. The polymer has a Tg of 21°C, a Td of 257°C, and a Mw of 2534 by gpc.

Example 16

SYNTHESIS OF A PURIFIED FLUORO- AND NITRO-CONTAINING POLY ESTER FROM 2-FLUORO-2-NIPROPANE-DIOL AND

4,8-DINITRAZA-UNDECAN0IC-1,11-DIACID CHLORIDE BY

A SOLVENT/NON-SOLVENT PRECIPITATION STEP

4,8-Dinitrazaundecanoic diacid chloride (3.45 g, 0.010 mol), 2-fluoro-2-nitro-1,3-propane-diol (1,54 g, 0.011 mol) and dry THF (40 ml) were charged to a 100 ml stirred flask. A solution of pyridine (1.2 ml,0.015 mol) in THF (5 ml) was added dropwise over a period of 30 minutes. The reaction was postreacted overnight, and then stripped to dryness. The residue was dissolved in 5 ml DMF, and the resulting solution was added dropwise to 100 ml of a rapidly stirred methanol. The solution was decanted, and the polymer was repeatedly washed with 3 x 25 ml of methanol and dried under vacuum at 60°C. 3.03 g (77.3% yield) of polymer was obtained. The polymer has a Tg of 20°C, a Td of 239°C, and a Mw of 5441 by gpc.

Example 17 SYNTHESIS OF A FLUORO- AND NITRO-CONTAINING POLY ESTER USING 2-FLUORO-2-NITRO-l,3-PROPANE-DIOL, DIETHYLENE GLYCOL AND 4,8-DINITRAZAUNDECANOIC- 1,11-DIACID CHLORIDE

Example 3 was repeated except two diols, 2- fluoro-2-nitro-1,3-propane-diol(30 mg, 0.22 mmol) and diethylene glycol (9 ul, 0.095 mmol) were used. 117 mg of a clear viscous polymer were obtained. The polymer has a Tg of -23.3°C, a Td of 252°C, and a Mw of 2016.

Example 18 SYNTHESIS OF A FLUORO- AND NITRO- CONTAINING

POLY ESTER USING 2-FLUORO-2- NITRO-1,3 PROPANE-DIOL AND

4,7-DI-NITRAZADECA 1,10-DIACID CHLORIDE

4,7-Dinitrazadecanoic-1,10-diacid chloride (104 mg, 0.32 mmol) and 2-fluoro-2-nitro-1,3- propane-diol(46 mg, 0.33 mmol) and dry THF (0.4 ml), stirred and

pyridine (51 ul. 0.63 mmol) was added dropwise at ambient temperature. The addition of pyridine resulted in a brown gummy product. After stirring at ambient temperature for 18 hr., 1 ml of THF and 0.2 ml of water were added. The reaction mixture was stirred for 2 hrs, and the liquid phase was decanted. The remaining solids were repeatedly washed with 3 x 0.4 ml of brine and 2 x 0.4 ml of water, and dried under high vacuum and heat. 140 mg of lightly yellow solids were obtained. The polymer has a Tg of 8°C, and a Td of 221°C, and a Mw of 4322 by gpc using DMF as the eluting solvent.

Example 19 SYNTHESIS OF A FLUORO- AND NITRO-CONTAINING

POLY ESTER USING 2-FLUORO-2- NITRO-l,3PROPANE-DIOL,

AND 4,7-DI- NITRAZADECA1,10-DIACID CHLORIDE AND

4,8-DINITUNPECANOIC-1,11-PIACIP CHLORIDE

4,7-Dinitrazadecanoic-, 10-diacid chloride (52 mg, 0.16 mmol), 4,8-dinitrazaundecanoic-1,11- diacid chloride (54 mg, 0.16 mmol) and 2- fluoro-2-nitro-1,3-propane-diol (48 mg, 0.35 mmol) were dissolved in 1 ml of dry THF, and pyridine (26 ul, 0.32 mmol) was added dropwise. The addition of pyridine resulted in a brownish precipitate. After stirring at ambient temperature for 18 hrs., 0.4 ml of water were added. The THF layer was separated, repeatedly washed with 4 x 0.4 ml brine, dried over anhydrous MgSO4, filtered, and stripped off the solvent. 141 mg of a viscous polymer were obtained. The polymer has a Tg of -27, a Td of 244, and a Mw of 1863 by gpc. Example 20

SYNTHESIS OF A NITRAZA- AND NITRO-CONTAINING POLY ESTER USING 4,8- DINITRAZAUNDECANOIC-1,11-DIACID CHLORIDE AND 2, 2-DINITRO-1,3-PROPANE-DIOL. A ETHYLENE

GLYCOL TERMINATED POLYMER

4,8-Dinitrazaundecanoic-1,11-diacid chloride ( 108 mg, 0.31 mmol) and 2,2- dinitro-1,3-propane-diol (50 mg, 0.30 mmol) were dissolved in 0.15 ml of dry THF. A mixture of pyridine (51 ul, 0.63 mmol) and dry THF (0.15 ml) was added dropwise. The addition resulted in a gradual formation of a white precipitate. The addition was completed in about 5 min. After stirring at ambient temperature for 18 hrs., 10 ul of ethylene glycol were added to convert any terminal acid chlorides to a hydroxyl group. The reaction mixture was stirred for another several hrs., and then added 1 ml of THF and few drops of water. 0.4 ml of brine were added after all the precipitates were dissolved. The THF layer was

separated, washed with 4 x 0.4 ml of brine, dried over with anhydrous MgSO4, filtered, and stripped off the solvent. 137 mg of a yellowish viscous polymer were obtained. The polymer has a Tg of -13 °C, a Td of

218.71, and a Mw of 3056.

Example 21

SYNTHESIS OF A NITRAZA- AND NITRO-CONTAINING POLY ESTER USING 4,8-DI-NITRAZAUNDE 1,11-DIACID CHLORIDE AND 2,2-DINITRPROPANEDIOL. ETHYLENE GLYCOL

TERMINATED POLYMER

This example is similar to example 7 except the post reaction time was reduced from 18 hrs. to 6.5 hrs. 122 mg of a slightly brown and viscous polymer were obtained. The polymer has a Mw of 4082.

Example 22

SYNTHESIS OF A PURIFIED NITRAZA- AND NITRO- CONTAINING

POLY ESTER FROM 4,8-DINITRAZA- UNDECAN1,11-DIACID

CHLORIDE AND 2,2-DINITRO-1,3-PROPANE-DIOL BY A

SOLVENT AND NON-SOLVENT PRECIPITATION STEP The procedure of example 4 was followed except 2,2-dinitro-1,3-propane-diol (1.84 g, 0.011 mol) was used instead of 2-fluoro-2,nitro-1,3- propane-diol (1.54 g, 0.011 mol). 3.65 g (83.3% yield) of polymer was obtained. The polymer has a Tg of 3.2°C, a Td of 212, and a Mw of 2081 by gpc.

Example 23

SYNTHESIS OF A NITRO- AND NITRAMINE- CONTAINING POLY

ESTER USING 4,8-DI-NITRAZAUNDECANOIC-1,11-DIACID

CHLORIDE AND 2,2 5,5-TETRANITRO-1.6-HEXANEDIOL 4,8-Dinitrazaundecanoic-1,11-diacid chloride

(2.72 g, 0.0079 mol) and 2,2,5,5-tetranitro- 1,6-hexanediol (2.24 g, 0.0075 mol) were added 4ml of dry THF and 1.34 ml (0.0165 mol) of dry pyridine. The addition of pyridine caused an exotherm and darkening of the reaction mixture, and additional dry THF (25 ml) was added. The reaction mixture was stirred at ambient temperature for 22.5 hrs. and then poured into 250 ml rapidly stirred methanol. The liquid solution was decanted, and the polymer was washed with 2 x 25 ml of methanol. After drying under high vacuum and heat at about 55°C, 4.35 g (about 100% yield) of polymer were obtained. The polymer has a Tg of 18.5°C, a Td of 216°C and a Mw of 3940 by gpc.

Example 24

SYNTHESIS OF NITRAMINE-CONTAINING POLY ESTER USING 4,8,-DINITRAZAUNDECANOIC DIACID CHLORIDE AND

2,5-DINITRAZA-1, 6-HEXANEDIOL.

A POLYMER TERMINATED WITH ETHYLENE GLYCOL

4,8-Dinitrazaundecanoic-1,11-diacid chloride (170 mg, 0.493 mmol) and 2,5-dinitraza-1,6- hexanediol (100 mg, 0.476 mmol) were placed in a dry hypovial, sealed, and added 1.6 ml of dry THF through a syringe. Pyridine (76 ul, 0.94 mmol) was added dropwise through a 100 ul syringe. The addition resulted in a white precipitate and was completed over a period about 4 min. After stirring at ambient temperature for about 18 hrs., 28 ul of ethylene glycol were added, and the reaction mixture was stirred for another 6 hrs. 0.4 ml of water were added, and the reaction mixture was

stirred to dissolve the precipitates. The THF layer was separated, washed with 4 x 0.4 ml of brine, dried over anhydrous MgSO44 filtered, and stripped off the solvent. 115 mg of a clear viscous polymer were

obtained. The polymer has a Tg of -22°C, a Td of 213°C, and a Mw of 1038 by gpc.

Example 25 SYNTHESIS OF NITRAMINE-CONTAINING POLY ESTER USING 4,8,-DINITRAZAUNDECANOIC DIACID CHLAND 2,5-DINITRAZA-1,6-HEXANEDIOL

4,8-Dinitrazaundecanoic-1,11-diacid chloride (170 mg, 0.493 mmol) and 2,5-dinitraza-1,6- hexanediol (100 mg, 0.476 mmol) were dissolved in 1.6 ml of dry THF. Pyridine ( 57 ul, 0.71 mmol) were added dropwise over a period of about 15 min. The addition of pyridine resulted in a white precipitate. After stirring at ambient temperature for about 18 hrs., 0,4 ml of water were added. The reaction mixture was stirred for

another 1 hr, until most of the precipitates were

dissolved. The THF layer was decanted from the

remaining undissolved small amount of a gummy material, washed with 0.4 ml of water and 2 x 0.4 ml of brine, dried over anhydrous MgSO4, filtered, and stripped off the solvent. 192 mg of a viscous polymer were obtained. The polymer has a Tg of -28°C, and a Td of 230°C, and a Mw of 1026. Comparative Example A

ATTEMPTED MELT POLYMERIZATION USING 4.8-

DINITRAUNDECANOIC-1,11-DIACID CHLORIDE AND

2,2,5,5-TETRANITRO-1,6-HEXANEDIOL 4,8-Dinitrazaundecanoic-1,11-diacid chloride (3.45 g, 0.010 mol), 2,2,5,5-tetranitro-1,6- hexanediol (2.99 g, 0.010 mol) and dry THF (2.5 ml) were charged to a dry 50 ml 2-neck flask equipped with a refluxing condensor and a gas inlet with a positive N₂ flow. The reaction mixture was stirred and heated to reflux in an oil bath at 70°C. After heating for 45 min., 2 ml of make-up THF was added. The reaction mixture was heated at 65 °C for additional 3.25 hrs., cooled and added 5 ml of THF, and poured in 100 ml of methanol. After

standing overnight, the liquid solution was decanted, and the residue was dried under high vacuum to give 0.25 g ( about 4.4% yield) of a brown oil.

Comparative Example P

ATTEMPTED MELT POLYMERIZATION USING

4,8-DINITRAZAUNDECANOIC-1,11-DIACID CHLORIDE

AND 2-FLUORO-2-NITRO-1,3-PROPANE-DIOL

2-Fluoro-2-nitro-1,3-propane-diol ( 1.39 g, 0.010 mol), 4,8-dinitrazaundecanoic-1,11-diacid chloride (3.08 g, 0.010 mol) and catalytic amount of PTSA.H₂O (0.0153 g) were charged to a 25 ml dry flask. The reaction mixture was heated to 100°C, and high vacuum was applied when the reaction mixture became melted.

After heating at 100°C for 4 hrs., the vacuum was removed. The reaction mixture was allowed to cool to 65°C, and dissolved in 5 ml of THF. The THF solution was poured into 100 ml of methanol but no precipitates of polymer was observed.

Comparative Example C SYNTHESIS OF FLUORO- AND NITRAMINE- CONTAINING

POLYESTER USING 2-FLUORO-2- NITRO-1,3-PROPANE-DIOL

AND 4,8.-DI- NITRAZAUNDECANOIC-1,11-DIACID

CHLORIDE WITHOUT THE ADDITION OF PYRIDINE

4,8-Dinitrazaundecanoic-1,11-diacid chloride (108 mg, 0.31 mmol) and 2-fluoro-2-nitro-1,3-propane- diol (46 mg, 0.33 mmol) were dissolved in 1.6 ml of dry THF and stirred at ambient temperature for about 18 hrs. 0.4 ml of water were added, and the reaction mixture was stirred for a few minutes. The THF layer was separated, washed with 4 x 0.4 ml of brine, dried over anhydrous MgSO4, filtered, and stripped off the solvent. 192 mg of a white solid were obtained. The white solid has a Mw by gpc of 579.

Comparative Example D SYNTHESIS OF FLUORO- AND NITRAMINE-CONTAINING

POLY ESTER USING 2-FLUORO-2-NITRO-1,3-PROPANE-DIOL

AND 4,7-DI- NITRAZADECANOIC-1,10-DIACID CHLORIDE

WITHOUT THE ADDITION OF PYRIDINE

This example is similar to example C except 4,7-dinitraza-decanoic-, 10-diacid chloride (104 mg, 0.32 mmol) was used instead of 4,8-dinitrazaundecanoic-1, 11-diacid chloride (108 mg, 0.31 mmol). 130 mg of a white solid were obtained. The white solid has a Mw of 538 by gpc. Comparative Example E

SYNTHESIS OF NITRAZAMINE-CONTAINING POLY ESTER USING 4,8- DINITRAZAUNDECANOIC-1,11-DIACID CHLORIDE AND 2,5-DINITR-1,6-HEXANEDIOL WITHOUT THE

ADDITION OF PYRIDINE

4,8-Dinitrazaundecanoic-1,11-diacid chloride (170 mg, 0.493 mmol) were dissolved in dry THF (0.3 ml) and added dropwise a solution of 1,5- dinitraza-1,6-hexanediol (100 mg, 0.476 mmol) dissolved in dry THF (0.6 ml). The addition was completed in about 5.5 min. After stirring at ambient temperrture for about 18 hrs., the reaction mixture was added water (0.4 ml) and stirred. The THF layer was separated, washed with 4 x 0.4 ml of brine, dried over anhydrous MgSO4, filtered, and stripped off the solvent. 235 mg of a waxy product were obtained. This waxy product has a Mw of 488 by gpc.

Claims

WHAT IS CLAIMED IS:

1. A proces-s for preparing a nitramine- containing diol characterized by the steps of:

(a) nitrating an amino alcohol to provide a nitraminoalkylnitrate ester,

(b) acetylating said nitraminoalkylnitrate ester to provide an acetylated ester, and

(c) hydrolyzing said acetylated ester with a strong acid in an organic solvent to yield a nitramino alcohol.

2. The process of claim 1 characterized in that said acetylating of step (b) is carried out using acetic acid and sodium acetate, and wherein the hydrolysis of step (c) is carried out using hydrochloric acid plus methanol, and wherein a product dehydration step is conducted between step (a) and step (b).

3. A nitramine-containing polymer characterized by an advantageous combination of a low viscosity and a low glass transition temperature, as well as resistance to hydrolysis, represented by the following empirical structural formula:

O NO₂ HO₂ O NO₂ NO₂

{[(C)_a(CH₂)bN(CH₂)_cN(CH₂)_d(C)_e]_x[OCH₂CH₂NCH₂CH₂(NCH₂CH₂)_fO]_y[(ORO)]_z}_n

wherein a and e have a value 0 or 1, b and d have values of 1 to 3, c has a value of 2 or 3, f has a value of 0 to 3, x has a value of 1, y has a value of from .10 to 1, and z has a value of from 0 to 0.9, with the proviso that the sum of y plus z is equal to 1, and wherein R is a linear or branched chain alkylene or alkylene ether radical having between 2 and 12 carbon atoms and having primary or secondary carbon atoms at points of

attachment of said radical in said polymer, and n has a value between 2 and 50.

4. A process for producing a nitramine- containing polymer characterized by the step of reacting a nitramine-containing diol with a nitramine-containing diacid or a nitramine-containing, dihalogen-containing compound.

5. The process of claim 4 characterized in that said step is carried out by a melt polymerization

reaction to form said nitramine-containing polymer while removing by-product hydrogen chloride during the course of said reaction.

6. The process of claim 4 characterized in that said by-product hydrogen chloride is removed by addition of a base.

7. The process of claim 4 characterized in that said nitramine-containing polymer is purified by

precipitation using a paired solvent/non-solvent mixture.

8. A polymer useful as an energetic binder and having a weight average molecular weight of between about 1,500 and about 5,000, said polymer being

characterized by the following empirical structural formula:

-(OCCH₂CH₂-R¹-CH₂CH₂COO-R²-O)_x-(OCCH₂CH₂

R¹ and R³ are independently selected from the following formula:

-N(NO₂)(CH₂)zN(NO₂)- wherein z is an integer of from 1 to 6 and

R², R⁴ are independently selected from the following formula:

-CH₂C(F)₁(NO₂)_mCH₂-,

-CH₂N(NO₂) (CH₂)_nN(NO₂)CH₂-,

-CH₂C(NO₂)₂(CH₂)_oC(NO₂)₂CH₂-, wherein l and m are independently 0 or an integer of from 1 to 6, and wherein the sum of l plus m is 2 ; and wherein n is an integer from 1 to 6, and o is an integer from 1 to 8.

9. The polymer of claim 8 characterized by being prepared by reacting at least one

nitramine-containing diacid chloride monomer with at least one nitro- or fluoro- containing diol monomer in an anhydrous organic solvent in the presence of a tertiary amine base at a reaction temperature of between about 0°C and about 50°C.

10. A process for producing a polymer

containing nitramine- and/or nitro- and/or fluoro-groups which is characterized by reacting at least one