Sol-gel manufactured energetic materials

• US 6,666,935 B1
• Filed: 09/09/1997
• Issued: 12/23/2003
• Est. Priority Date: 09/09/1997
• Status: Expired due to Fees

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Simpson, Randall L., Lee, Ronald S., Swansiger, Rosalind W., Tillotson, Thomas M., Hrubesh, Lawrence W., Fox, Glenn A.
• Primary Examiner(s): Carone, Michael J.
• Assistant Examiner(s): Felton, Aileen B.
• Application Number:
  US08/926,357
• Time in Patent Office: 2,296 Days
• Field of Search: 149/19.92, 149/19.1, 149/76, 149/109.6
• US Class Current: 149/19.92
• CPC Class Codes: B01J 13/0091 Preparation of aerogels, e.g. xerogels
• CPC Class Codes: C06B 21/0066 by granulation, e.g. flaking
• CPC Class Codes: C06B 21/0091 Elimination of undesirable or temporary components of an intermediate or finished product, e.g. making porous or low density products, purifying, stabilising, drying; Deactivating; Reclaiming; porous inert particles or chemicals compounded for these purposes C06B23/00
• CPC Class Codes: C06B 45/00 Compositions or products which are defined by structure or arrangement of component of product explosive charges of particular form or shape F42B1/00, F42B3/00
• CPC Class Codes: Y02P 20/54 using solvents, e.g. supercritical solvents or ionic liquids
• CPC Class Codes: Y10S 977/70 Nanostructure
• CPC Class Codes: Y10S 977/775 Nanosized powder or flake, e.g. nanosized catalyst
• CPC Class Codes: Y10S 977/835 Chemical or nuclear reactivity/stability of composition or compound forming nanomaterial
• CPC Class Codes: Y10S 977/895 having step or means utilizing chemical property
• CPC Class Codes: Y10S 977/896 Chemical synthesis, e.g. chemical bonding or breaking

Abstract

Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

Claims

1. A process comprising:

providing a solution containing a plurality of reactive monomeric molecules;

providing a catalyst;

providing a plurality of pore-filling molecules;

adding said catalyst to said reactive monomeric molecule solution to form a gel having a three-dimensional cross-linked skeleton of reacted monomeric molecules and a plurality of pores;

drying said gel; and

incorporating said plurality-of pore-filling molecules into said gel such that said pore-filling molecules fill said pores to form an energetic material having a fuel constituent and an oxidizer constituent, wherein either (1) said skeleton of reacted monomeric molecules comprise the fuel constituent and said pore-filling molecules comprise the oxidizer constituent or (2) said skeleton of reacted monomeric molecules comprise the oxidizer constituent and said pore-filling molecules comprise the fuel constituent, said incorporating step occurring either (1) prior to said gel formation, but after said catalyst addition or (2) after said gel has been formed and dried.

2. The process recited in claim 1, wherein said reactive monomeric molecules comprise organic molecules and said pore-filling molecules comprise at least one metal.

3. The process recited in claim 1, wherein said reactive monomeric molecules comprise metal oxides and said pore-filling molecules comprise at least one metal.

4. The process recited in claim 1, wherein said reactive monomeric molecules comprise organic molecules and said pore-filling molecules comprise ammonium perchlorate.

5. The process recited in claim 1, wherein said drying is accomplished by slow evaporation of the liquid phase of the gel.

6. The process recited in claim 1, wherein said drying is accomplished by supercritical extraction of the liquid phase of the gel.

7. The process recited in claim 1, wherein said pore-filling molecules comprise a powdered material, said powdered material being incorporated into the gel by adding said powdered material to the reactive monomer/catalyst solution prior to gellation.

8. The process recited in claim 1, wherein said pore-filling molecules comprise metal particles, said metal particles being incorporated into the gel after the gel has been dried by electrochemical precipitation.

9. The process recited in claim 1, wherein said reactive monomeric molecules comprise a mixture of resorcinol (1,3-dihydroxybenzene) and formaldehyde in a molar ratio of 1:

2, respectively, said catalyst comprises sodium carbonate, and said pore-filling molecules comprise ammonium perchlorate, and wherein said ammonium perchlorate is added to said resorcinol/formaldehyde/sodium carbonate solution prior to gellation.

10. The process recited in claim 9, wherein said drying is accomplished by slow evaporation of the liquid phase of the gel.

11. The process recited in claim 10, wherein said drying is accomplished by low temperature carbon dioxide supercritical extraction.