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Patent Issued for Carbon Nanotubes Containing Confined Copper Azide

July 30, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Gogotsi, Yury (Ivyland, PA); Pelletier, Valarie (Troy, NY); Forohar, Farhad (LaPlata, MD); Bichay, Magdy (Springfield, VA), filed on August 28, 2013, was published online on July 15, 2014.

The patent's assignee for patent number 8778105 is The United States of America as Represented by the Secretary of the Navy (Washington, DC).

News editors obtained the following quote from the background information supplied by the inventors: "The currently used primary explosives, such as lead azide and lead styphnate, present serious health hazards due to the toxicity of lead. There is a need to replace them with equally energetic but safer-to-handle and more environmentally friendly materials. Copper azide is more environmentally acceptable, but very sensitive and detonates easily from electrostatic charges during handling."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "In some aspects, the invention concerns methods for encapsulating copper azide inside AAO-templated carbon nanotubes. This has resulted in making an explosive device more than 100 times smaller in size than human hair. Initiation of azide inside the nanotubes did not lead to tube wall fracture. The detonation wave apparently propagated along the nanotube channel, providing an opportunity for directing the decomposition gas flow and possibly more efficient initiation of the secondary explosives. Hollow Cu/Cu--O containing nanoparticles were produced as a result of the encapsulated copper azide nanoparticle initiation. This experimental technique can be used to encapsulate a wide variety of energetic materials inside carbon nanotubes. A greener approach toward energetic nanomaterials has a potential to eliminate lead from primary explosives.

"Compared to the current primary explosive materials, such as lead azide and lead styphnate, which are highly sensitive and present serious health hazards due to the toxicity of lead, this novel energetic composite material is safer to handle, uses environmentally friendly materials and processes, and is less sensitive to electrostatic charges, making it less likely to accidentally detonate. By containing the nanoenergetic material inside the CNTs, energetic properties are preserved while increasing safety of handling. Containment also increases stability, minimizing friction and static electricity effects, improving environmental and thermal stability. Using nanoenergetic materials increases the energy release due to the high aspect ratio of the copper azide nanoparticles.

"In some embodiments, the invention concerns compositions comprising carbon nanotubes and, residing within (such as, encapsulated within) at least a majority of said nanotubes, copper azide. In certain embodiments, the carbon nanotubes have internal diameters of 100-300 nm. The invention also concerns explosives comprising compositions disclosed herein.

"In other embodiments, the invention concerns methods of forming nanotube structures comprising: placing CuO nanoparticles within carbon nanotubes to produce packed nanotubes; contacting the packed nanotubes with hydrogen to produce reduced packed nanotubes (which can comprise a significant amount of elemental copper, any unreacted residual copper oxide can potentially convert to copper (II) azide); and contacting the reduced packed nanotubes with hydrazoic acid to produce copper azide containing carbon nanotubes. Copper azide can comprise copper (I) azide and/or copper (II) azide. In some embodiments, the hydrazoic acid is produced in gaseous form by heating a mixture of sodium azide with excess stearic acid at a temperature of at least 80.degree. C.

"Other embodiments concern methods of forming nanotube structures comprising: forming carbon nanotube by chemical vapor deposition of ethylene on an aluminum oxide substrate; placing CuO nanoparticles within the carbon nanotubes to produce packed nanotubes; contacting said packed nanotubes with sodium hydroxide to dissolve the aluminum oxide to produce released nanotubes; contacting the released carbon nanotubes with hydrogen to produce reduced packed nanotubes; and contacting the reduced packed nanotubes with hydrazoic acid to produce copper azide containing carbon nanotubes."

For additional information on this patent, see: Gogotsi, Yury; Pelletier, Valarie; Forohar, Farhad; Bichay, Magdy. Carbon Nanotubes Containing Confined Copper Azide. U.S. Patent Number 8778105, filed August 28, 2013, and published online on July 15, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8778105.PN.&OS=PN/8778105RS=PN/8778105

Keywords for this news article include: Carbon Nanotubes, Chemicals, Chemistry, Emerging Technologies, Fullerenes, Hydrazoic Acid, Nanoparticle, Nanotechnology, The United States of America as Represented by the Secretary of the Navy.

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Source: Journal of Engineering


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