DIA 2013 Insensitive Munitions & Energetic Materials Technology Symposium SYTHESIS OF EERGETIC MATERIALS USIG CARBO AOSTRUCTURES Chang Ha Lee, Seungjoo Haam Converged Energy Materials Research Center (CEMRC) Dept. of Chemical and Biomolecular Eng., Yonsei University, Seoul, Korea (leech@yonsei.ac.kr) Hyerim Choi, Woo-Jae Kim Dept. of Chemical and Biological Eng., Gachon University, Seongnam, Korea Jung Min Lee, Hyoun Soo Kim Agency for Defense Development, Daejeon, Korea
the ext-generation Converged Energy Materials Research Center (CEMRC) Director: Prof. Chang-Ha Lee Yonsei University Period: 2012 2020 Research Group: 11 Univ. & 1 Research Institute (34 doctors) Budget: about 10 mill. USD/9-yr Design and synthesis capability for the next-generation converged energetic materials Development of more powerful & less sensitive energetic materials Eco-friendly green technology for decayed energetic materials to valuable compounds
Design for Energetic Materials Formulation Destruction, incineration, explosion, etc for decayed energetic materials pollution, resource waste, safety issues Multi-functional Energetic Particles Demilitarization of Decayed Energetic Materials O 2 O O 2 O 2 O 2 O OO 2 O 2 O 2 Tris-X H 2 H 2 H 2 O 2 O 2 O 2 H 2 H 2 O 2 H DAPP O 2 Today s Topic O 2 O 2 O 2 O 2 O 2 2 O O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 Target 1 Target 2 Target 3
Research on Energetic materials Research on energetic materials focuses on Enhancing the power of its composites Increasing its insensitivity & stability Controlling the detonation properties Mixing several chemicals to tune the explosive reactivity Potential benefits of nano-energetic materials: More powerful Higher density. More reliable & reproducible Controlled rate of energy release. Safer to handle Reduced sensitivity.
anomaterials : ew platform for energetic materials anomaterials High Thermal Conductivity High Surface Area Stabilization Part I A Carbon anotube B Porous Carbon anoparticle Part II Advantages of anomaterials as new energetic materials anomaterials as new energetic materials offer - Increased surface areas for higher density (1) the potential of high heat release rates, (2) increased combustion efficiencies, -Enhancement of chemical reactivity by high thermal conductivity (3) tailored burning rates, and (4) reduced sensitivity. -Ability to form composites with fuels by surface functionalization anostructured Energetic Materials is a new concept composite powder, which can dramatically improve the performance of gunpowder and explosives
Single-Walled Carbon anotubes (SWT) Graphite Graphene Carbon anotubes Extract layer Fold layer Method of rolling graphene determines electronic property of SWTs Conduction band Metallic Semiconducting gap Valence band node CT electronic dispersion (e.g. Semiconducting CT) Graphene electronic dispersion (Zero-gap semiconductor) CT electronic dispersion (e.g. Metallic CT) Part I: Carbon anotube SWTs can be either Metallic or Semiconducting
Properties of Carbon anotubes Mobility (cm 2 /V s) CT Silicon GaAs 1400 8500 SC CT M CT 100,000 High Performance Transistor Current Density (A/cm 2 ) CT Al Cu 800 4020 10 9 Display Solar Cell Surface Area (m 2 /g) Thermal Conductivity (W/m K) CT Activated C Silica CT Silicon Diamond 149 500 800 2320 1500 3500 Interconnect Highly dense Super capacitor energetic materials Thermal Heat conduits Sink Ultimate Strength (GPa) CT C Fiber Steel 4 1 130 Propellant Composite composites Part I: Carbon anotube
Issues and Motivations CT guide thermal waves generated by the combustion of Cyclotrimethylene trinitramine (TA) (Choi et al., ature Mater. 9, p424, 2010) The reaction velocity of TA coated on CT : 1,000~10,000 times faster than that of bulk TA CT with high thermal conductivity: Guide a chemically produced thermal wave Technology Issues Heterogeneities in the thickness of MWTs as well as the TA coated on the MWT surface of MWT/TA composites Irregular performance along axial positions of the composites Performance controllability issue Part I: Carbon anotube
Objectives 1. Achieve homogeneities of energetic materials-ct composites (control issue) CT : Single-walled carbon nanotube (vs. multi-walled carbon nanotube) Energetic materials : chemical attachment (vs. physical ) 2. Increase combustion efficiency CT with high conductivity Key factors investigated We synthesized a series of nitrophenyl decorated CT using diazonium chemistry explored CT, with energetic materials, can release energy in a controllable manner investigate how thermal conductivity of CT affects self-propagating explosive reactions Part I: Carbon anotube
Diazonium chemistry: attach energetic materials on CT Chemical Potential of Diazonium-SWT system Diazonium SWT Reaction Scheme of Diazonium-SWT system O 2 + BF 4 - O 2 SDS/D 2 O ph = 5.5 45 o C Electron transfer reaction between CT Diazonium Favored when oxidation potential of CT > reduction potential of diazonium itrobenzene diazonium : highly reactive towards CT Diazonium chemistry is efficient scheme to attach energetic molecule (itrobenzene) onto CT surface homogeneously with high density Part I: Carbon anotube
Covalent reaction scheme mono- nitrobenzene diazonium synthesis OBF 4 O 2 H 2 Acetonitrile 2, -20 o C Stored at -20 o C HO + BF - O 2 4 Ethyl Ether -20 o C Solid precipitate Dissolved in H 2 O covalent reaction di-nitrobenzene attached CT O 2 + BF 4 - O 2 OBF 4 Acetonitrile 2, -20 o C SDS/H 2 O ph = 5.5 45 o C SDS/H 2 O ph = 5.5 45 o C Reacted Part I: Carbon anotube
Experimental Energetic Materials Used di-nitroaniline alone di-nitrobenezene Diazonium + CT di-nitrobenezene functionalized CT mono-nitrobenezene functionalized CT Physically mixed Chemically bonded SWT with different thermal conductivity used - HiPco SWT (Hi-Pressure CO method) : low thermal/electrical conductivity - Arc SWT (Arc Discharge method) : high thermal/electrical conductivity Part I: Carbon anotube
Energetic materials-ct composites formation ( ) ( ) O e - Diazonium salt o reaction O 2 -attached Energy x Density of States Reaction Raman : D-band increases UV-vis-nIR: absorption decays Absorbance 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 HiPco SWT HiPco SWT+mono-nitro phenyl HiPco SWT+di-nitro phenyl Absorbance 1.2 1.0 0.8 0.6 0.4 0.2 Arc SWT Arc SWT + mono-nitro phenyl Arc SWT + di-nitro phenyl () di-nitrophenyl functionalized 1000 1100 1200 1300 1400 1500 1600 1700 1800 mono-nitrophenyl functionalized 400 600 800 1000 1200 Wavelength(nm) 400 600 800 1000 1200 Wavelength(nm) 1000 1100 1200 1300 1400 1500 1600 1700 1800 Raman Shift (cm -1 ) itrophenyl groups (energetic materials) successfully attached to SWT (monolayer deposition) Part I: Carbon anotube
Chemical Attachment Effect Alone Physically mixed Chemically attached Di-nitroaniline Heat Flow (mw) 20 15 10 5 0-5 -10 melting 300.30 o C 373.60 o C 280.33 o C decomposition 300.30 o C -15 100 200 300 400 500 Temperature( o C) Medium temperature Wt Corrected Heat Flow (mw/g) 100 373.63 o C 80 60 40 20 0 100 200 300 400 500 Temperature( o C) Broad range High temperature Wt Corrected Heat Flow (mw/g) 20 15 280.33 o C 100 200 300 400 500 Temperature ( o C) arrow range Lower temperature Part I: Carbon anotube
Experimental Synthesis of silica nanoparticles as a template of nanoparticle. Hard sip Porous sip sip w/ ultralarge pore Synthesis of carbon nanoparticles - AlCl 3 6H 2 O was added to strengthen the silica nanoparticles - Phenol and Paraformaldehyde was added and heated for 36h to generate carbon nanoparticles. Part II: Porous Carbon anoparticle
Synthesis of silica nanoparticles as a template of Porous Carbon anoparticle sphere silica nanoparticles Porous Layer coated Silica anoparticles Pore-Enlarged Silica anoparticle (scale bar : 50 nm) As a template for the porous carbon nanoparticle, we synthesized silica nanoparticles which possess multi-channel. In order to load large amount of energetic materials, we made sphere silica nanoparticles inside, which will be removed and put out vacant volume as well as enlarge the pore diameter Part II: Porous Carbon anoparticle
Synthesis of Carbon anoparticle Carbon anoparticle (Scale Bar : 100 nm) silica nanoparticles Carbon materials coated nanoparticles We coated the carbon materials on the silica nanoparticles. And it was confirmed that the structure of nanoparticles were maintained Future Work : we plan to remove the silica template in order to bring out the vacant volume to load energetic materials inside vacant space. Part II: Porous Carbon anoparticle
Conclusions 1. Homogeneous energetic materials-ct composites were successfully formed using covalent chemistry. 2. Chemically bonded composites release energy at low temperatures over physically mixed ones. 3. Composites with highly conductive CT show explosion at lower temperatures. 4. Synthesis of silica nanoparticles as a template was successfully fabricated. 5. For the better loading capacity, silica template of carbon nano particles are planned to be evacuated. 6. Enlarged cavity with carbon materials in carbon nanoparticles are expected to contribute better performances in loading and stabilizaing large amount of energetic materials.
KISHEM-3 will be held in September, 2014: Yonsei University in Seoul, Korea (More information: http://www.kishem.co.kr) TOPICS Propellants High Explosives Insensitive Munitions Ageing Performance Synthesis Transformation of Decayed/Expired Materials Characterization ano-materials Improvements Manufacturing Detonation Physical Properties Theory IMPORTAT DATES Due date for One-page Abstract: May 15, 2014 Abstract Acceptance otice: June 30, 2014 Due date for Registration: July 31, 2014 Session Schedule otice: End of July, 2013 Yonsei Univ. Han River at night
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