Alliant Techsystems Inc.

Andrew J Sanderson

Wayne Edwards

Louis F Cannizzo

Thomas K Highsmith

Kirstin F Warner

Robert B Wardle

Robert M Hajik

Laura J Martins

Stephen P Velarde

Paul C Braithwaite

Harold E Johnston

William W Edwards

Michael A Dewey

Jeffrey D Akester

Jeff F Widener

Richard S Hamilton

Methods of purifying BT are disclosed. The method comprises adding at least one polyhydroxyl compound to a crude BT mixture comprising BT and at least one boron-containing compound to form a polyhydroxyl compound/BT mixture. In one embodiment, the polyhydroxyl compound/BT mixture is then heated to a temperature greater than the boiling point of BT but less than the boiling point of the at least one polyhydroxyl compound. In another embodiment, the polyhydroxyl compound/BT mixture is heated to a temperature greater than the melting point of the at least one polyhydroxyl compound, and then to a temperature greater than the boiling point of BT but less than the boiling point of the at least one polyhydroxyl compound. A composition comprising BT is also disclosed.

Methods of purifying 1,2,4-butanetriol

This thermoplastic elastomer is present in a substantially solid state suitable for use as a binder for a propellant, explosive, and/or gas generant of a supplemental restraint system. The thermoplastic elastomer is formed from a composition including A blocks which are crystalline at temperatures below about 75&#xb0; C. and B blocks which are amorphous at temperatures above about &#x2212;20&#xb0; C. The A blocks are derived from oxetane derivatives and the B blocks are derived from oxiranes and derivatives thereof. The A blocks and B-blocks are end-capped with a diisocyanate having a first isocyanate moiety that is substantially more reactive with the terminal groups of the blocks than the second isocyanate moiety, whereby the more reactive first isocyanate moiety is capable of reacting with the terminal groups of the blocks, leaving the less reactive second isocyanate moiety free and unreacted. The end-capped A blocks and the end-capped B blocks are linked together with a linking compound having two isocyanate-reactive groups which are sufficiently unhindered to react with the free and unreacted isocyanate moieties of the end-capped polymers.

Synthesis of energetic thermoplastic elastomers containing both polyoxirane and polyoxetane blocks

A method is provided for preparing thermoplastic elastomers. A blocks of the thermoplastic elastomers are crystalline at temperatures below about 60&#xb0; C. and are derived from oxetane derivatives and/or tetrahydrofuran derivatives. B blocks of the thermoplastic elastomer are amorphous above about &#x2212;20&#xb0; C. and are derived from oxetanes, tetrahydrofuran, oxiranes, and derivatives thereof. According to this method, the A and B blocks are dissolved into solution containing a non-halogenated solvent, preferably tetrahydrofuran, then dried by azeotropic distillation. The dried blocks are end-capped with a diisocyanate, preferably a diisocyanate having one isocyanate moiety substantially more reactive with the terminal groups of the blocks than the other isocyanate moiety of the diisocyanate. The end-capped blocks are then linked together with a linking compound.

Method for the synthesis of energetic thermoplastic elastomers in non-halogenated solvents

A process is provided in which at least one multi-functional alcohol having a hydroxyl functionality of at least two serves as a polymerization initiator. The multi-functional alcohol initiator is optionally, although preferably, reacted with a catalyst to form a catalyst-initiator complex, which is then used in the polymerization of glycidyl nitrate. The resulting poly(glycidyl nitrate) has a functionality substantially equivalent in number to the hydroxyl functionality of the multi-functional alcohol initiator. The poly(glycidyl nitrate) is cross-linked with at least one aromatic polyisocyanate having at least one aromatic ring and, on average, more than two isocyanate moieties bonded directly to the aromatic ring.

Process for making stable cured poly(glycidyl nitrate) and energetic compositions comprising same

This thermoplastic elastomer is present in a substantially solid state suitable for use as a binder for a propellant, explosive, and/or gas generant of a supplemental restraint system. The thermoplastic elastomer is formed from a composition including A blocks which are crystalline at temperatures below about 75&deg; C. and B blocks which are amorphous at temperatures above about &minus;20&deg; C. The A blocks are derived from oxetane derivatives and/or tetrahydrofuran derivatives. The B blocks are derived from oxetanes, tetrahydrofuran, oxiranes, and derivatives thereof. The A and B blocks are end-capped with at least one diisocyanate and linked with at least one difunctional oligomer having two functional groups which are reactive with free and unreacted isocyanate moieties of the diisocyanate.

Synthesis of energetic thermoplastic elastomers containing oligomeric urethane linkages

A process is provided in which at least one polyol having a hydroxyl functionality of at least three, preferably four, serves as a polymerization initiator. The polyol initiator is optionally, although preferably, reacted with a catalyst to form a catalyst-initiator complex, which is then used in the polymerization of glycidyl nitrate. The resulting polyfunctional poly(glycidyl nitrate) has a functionality substantially equivalent in number to the hydroxyl functionality of the polyol. The poly(glycidyl nitrate) is cross-linked with at least one aromatic diisocyanate having at least one aromatic ring and two isocyanate moieties bonded directly to the at least one aromatic ring. Examples of the aromatic diisocyanate include toluene diisocyanate, phenylene diisocyanate, and/or methylene di-p-phenylene diisocyanate.

Process for making stable cured poly(glycidyl nitrate)

A combustible cartridge case is provided that includes at least one energetic thermoplastic homopolymer or copolymer derived from, at least in part, poly(bis-azidomethyloxetane) prepolymer blocks terminated with isocyanate-reactive groups, such as hydroxyl groups. Chain linking of the prepolymer blocks is performed with diisocyanates for end-capping the prepolymer blocks, and a difunctional linking compound for linking the end-capped prepolymer blocks. The energetic thermoplastic is preferably capable of being pressed, extruded, rotational molded, injection loaded, or otherwise shaped into a desired configuration. Also provided is a chain-extended poly(bis-azidomethyloxetane) homopolymer derived from bis-azidomethyloxetane prepolymer blocks, which are terminated with isocyanate-reactive groups and chain extended with at least one diisocyanate end-capping compound and at least one difunctional linking compound.

Chain-extended poly(bis-azidomethyloxetane), and combustible cartridge cases and ammunition comprising the same

A process for preparing 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo&lsqb;5.5.0.0  &rsqb;-dodecane involves reacting at least one hexa-substituted piperazine derivative with at least one nitrate source and optionally at least one strong acid and heating the mixture to a temperature sufficient to induce an exothermic initial stage of the between the hexa-substituted piperazine derivative and the nitrate source. The mixture is maintained at a temperature in a range of at least ambient to not more than about 80&deg; C. during the exothermic initial stage and at least a portion of a subsequent non-exothermic intermediate stage of the reaction by cooling the mixture during at least a portion of the exothermic initial stage of the reaction so that the reaction proceeds in a controlled manner. The mixture is then cooled to a temperature sufficiently low to prevent commencement of an exothermic NO autocatalytic stage.

Synthesis for 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo&lsqb;5.5.0.05,903,11&rsqb;-dodecane

In this process 2,6,8,12-tetraacetyl-2,4,6,8,10,12-hexaazatetracyclo-&lsqb;5.5.0.0  &rsqb;-dodecane (&ldquo;TADH&rdquo;) is subjected to nitrolysis in the presence of a mixed acid to form HNIW. The mixed acid comprises at least one nitronium ion source (preferably nitric acid) and at least one strong acid (preferably sulfuric acid) capable of generating a nitronium ion from the source. The ratio of nitronium ion source to strong acid and the amount of TADH used are selected so that, in the event that the nitrolysis reaction is carried out at 85&deg; C., 99% nitramine conversion will occur within ten minutes.

Process for making 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo&lsqb;5.5.0.05,903,11&rsqb;-dodecane

Glycerol is nitrated with at least one nitrating source in a solvent to form a nitrated glycerol solution containing dinitroglycerin. The nitrated glycerol solution is treated with at least one cyclizing agent to convert the dinitroglycerin into glycidyl nitrate, which is polymerized into poly(glycidyl nitrate) (PGN). Distillation or other vaporization techniques are not required to remove nitroglycerin from the glycidyl nitrate prior to polymerization of the glycidyl nitrate. Rather, the nitroglycerin can be carried along with the dinitroglycerin during polymerization. As a consequence, the glycidyl nitrate is not exposed to elevated temperatures sufficient to cause accidental explosion or deflagration of the nitrate ester. Still more preferably, the glycidyl nitrate is not heated above room temperature at any time prior to polymerization. Moreover, given the high energy performance of nitroglycerin, the nitroglycerin can optionally be retained with the PGN, i.e., not washed out, for subsequent processing and end use.

Polymerization of poly(glycidyl nitrate) from high purity glycidyl nitrate synthesized from glycerol

CL-20 is crystallized from a solution containing a CL-20 organic solvent and a CL-20 non-solvent miscible with the solvent. The CL-20 non-solvent is a nitrate ester, preferably poly(glycidyl nitrate) and/or triethyleneglycol-dinitrate, although other nitrate ester plasticizers having acceptable volatilities and impact sensitivities can be used. The solution is saturated with CL-20, and CL-20 is then crystallized from the saturated solution by adding &egr;-polymorph CL-20 crystalline seeds to the solution and evaporating off the CL-20 solvent, preferably under vacuum. The nitrate ester non-solvent is then separated from the crystalline CL-20, such as by filtration of the CL-20 crystals or by diluting the slurry of non-solvent and CL-20 with an environmentally acceptable solvent that is miscible with the non-solvent but in which the CL-20 is insoluble.

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North Ogden, UT, United States of America

Andrew J Sanderson