US-20260125610-A1 - THERMOPLASTIC-BASED ENERGETIC MATERIAL PRODUCTION

US20260125610A1US 20260125610 A1US20260125610 A1US 20260125610A1US-20260125610-A1

Abstract

An energetic material includes a matrix of a thermoplastic polymer and an oxidizer distributed in the thermoplastic polymer matrix. The energetic material can be produced, for example, by a method that includes adding the oxidizer to the thermoplastic polymer while the thermoplastic polymer is in a softened state to form a mixture, which is then cooled to produce the energetic material.

Inventors

Michael Joseph Baier
Nicholas Shane Podany

Assignees

FIREHAWK AEROSPACE, INC.

Dates

Publication Date: 20260507
Application Date: 20241101

Claims (20)

1 . An energetic material comprising: a matrix of a thermoplastic polymer; and an oxidizer distributed in the thermoplastic polymer matrix, wherein the energetic material is in the form of pellets sized to be used as feedstock for additive manufacturing.
2 . (canceled)
3 . (canceled)
4 . The energetic material of claim 1 , wherein the pellets of energetic material have at least one dimension in the range of 2-4 mm.
5 . The energetic material of claim 1 , wherein the energetic material comprises a solid propellant material.
6 . The energetic material of claim 1 , wherein the energetic material is in the form of a powder.
7 . The energetic material of claim 1 , comprising a solid fuel additive distributed in the thermoplastic polymer matrix.
8 . The energetic material of claim 7 , wherein the solid fuel additive comprises metal particles.
9 . The energetic material of claim 7 , wherein the metal particles comprise nanoscale or microscale metal particles.
10 . The energetic material of claim 7 , wherein the metal particles comprise nanoscale or microscale particles of aluminum.
11 . The energetic material of claim 7 , wherein the solid fuel additive and the oxidizer are present in the energetic material at a stoichiometric ratio with respect to combustion of the metal.
12 . The energetic material of claim 7 , wherein the energetic material comprises from about 10 weight percent (wt. %) to about 20 wt. % of the solid fuel additive.
13 . The energetic material of claim 1 , wherein the energetic material comprises from about 50 wt. % to about 75 wt. % of the oxidizer.
14 . The energetic material of claim 1 , wherein the energetic material comprises from about 10 wt. % to about 25 wt. % of the thermoplastic polymer.
15 . The energetic material of claim 1 , wherein the energetic material comprises from about 20 volume percent (vol. %) to about 50 vol. % of the thermoplastic polymer.
16 . The energetic material of claim 1 , wherein the oxidizer comprises one or more of potassium nitrate, potassium perchlorate, ammonium nitrate, ammonium perchlorate, or sodium perchlorate.
17 . The energetic material of claim 1 , wherein the thermoplastic polymer comprises a thermoplastic polyurethane.
18 . The energetic material of claim 1 , wherein the thermoplastic polymer comprises a mixture of multiple thermoplastic polymers.
19 . The energetic material of claim 1 , wherein the thermoplastic polymer has a melt temperature between about 120° C. and 190° C.
20 . The energetic material of claim 1 , wherein the energetic material has a melt temperature between about 120° C. and 190° C.

Description

TECHNICAL FIELD This disclosure relates to production of thermoplastic-based energetic material. BACKGROUND There are various types of chemical rocket propulsion systems. Liquid rocket engines use liquid-phase propellants. Solid rocket motors use solid-phase propellants. In some cases, additive manufacturing can be used to deposit propellant material and solidify to form a structure composed of a stacked set of layers for forming a solid propellant material. Additive manufacturing allows for the ability to produce complex shapes or geometries that may otherwise be infeasible to construct by hand, including hollow parts or parts with internal structures. SUMMARY This disclosure describes technologies relating to thermoplastic-based energetic material. The subject matter described in this disclosure can be implemented in particular implementations, so as to realize one or more of the following advantages. The energetic material described is shelf-stable and can be stored for extended periods of time (e.g., for at least six months) after production and before use. The energetic material described includes thermoplastics, which allows the energetic material to be re-processable. The re-processability of the energetic material provides flexibility in that characteristics of the energetic material can be altered, if desired, by re-processing the energetic material (e.g., by melting) and introducing additional components into the formulation and/or diluting components of the formulation. In contrast, other conventional energetic materials including thermoset material(s) cannot be re-processed because once cured, thermosets remain permanently cured. In such conventional energetic materials, if there are any flaws or concerns with certain units produced from a batch of materials, such units cannot be re-processed and would likely need to be disposed. The re-processability of the energetic material provides flexibility in manufacturing as well. For example, the energetic material can be re-processed by an additive manufacturing system for depositing the energetic material onto the surface of another material, such as a solid rocket motor. As another example, the energetic material can be re-processed by an additive manufacturing system for 3D printing the energetic material to form a desired shape of the energetic material. The systems and processes described are flexible in that they can be operated in a batch process or a continuous process. A continuous process can achieve the same production throughputs as an analogous batch process, but at any specific moment in time, less of the active material (e.g., combustion material) is in use in comparison to the analogous batch process, resulting in less waste of base materials and enhanced safety. In some cases, the energetic material includes a solid fuel additive that increases an energy density of the energetic material, which can be particularly useful for solid rocket motors or hybrid rocket engines. The details of one or more implementations of the subject matter of this disclosure are set forth in the accompanying drawings and the description. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims. DESCRIPTION OF DRAWINGS FIG. 1A is a schematic diagram of an example thermoplastic-based energetic material. FIG. 1B is a schematic diagram of an example feedstock supply kit including the thermoplastic-based energetic material of FIG. 1A. FIG. 2 is a schematic diagram of an example system for producing a thermoplastic-based energetic material. FIG. 3 is a flow chart of an example method for producing a thermoplastic-based energetic material. FIG. 4 is a flow chart of an example method for producing a thermoplastic-based energetic material. FIG. 5 is a flow chart of an example method for producing and using a thermoplastic-based energetic material. FIG. 6 is a flow chart of an example method for producing and storing a thermoplastic-based energetic material. DETAILED DESCRIPTION This disclosure describes production of thermoplastic-based energetic material. The thermoplastic-based energetic material can be used, for example, to fabricate solid propellant grains for solid rocket motors or to fabricate hybrid rocket engine fuel grain assemblies including both hybrid fuel grain material and solid propellant. FIG. 1A is a schematic diagram of an example thermoplastic-based energetic material 100. The energetic material 100 includes a thermoplastic polymer matrix 102. The energetic material 100 includes an oxidizer 104 that is distributed in the thermoplastic polymer matrix 102. In some implementations, as shown in FIG. 1A, the energetic material 100 is in the form of pellets. The pellets of the energetic material 100 can be sized, for example, to be used as feedstock for additive manufacturing (e.g., 3D printing). In some implementations, the pellets of the energetic material 100 have at least o