Glenn Research Center at Lewis Field
NANO-CASTED METAL OXIDE AEROGELS
AS DUAL PURPOSE STRUCTURAL COMPONENTS
FOR SPACE EXPL...
Glenn Research Center at Lewis Field
Motivation For Research
Conductive
Magnetic
Light Emitters
•Electrical Conduits
•Sens...
Glenn Research Center at Lewis Field
Overview
• Preparation of Metal Oxide Aerogels:
– Overall process and chemical reacti...
Glenn Research Center at Lewis Field
Aerogels
nonporous
primary
particles
(<1 nm; dense silica)
mesopores
channels to
micr...
Glenn Research Center at Lewis Field
MOx Aerogels Prepared
Gelled and Tested Attempted; No Gellation
Rare-Earth
Aerogels:
...
Glenn Research Center at Lewis Field
Silicon Dioxide Aerogels: Chemistry
Note: Same chemistry was used to prepare vanadium...
Glenn Research Center at Lewis Field
Silicon Dioxide Aerogels: Structure
O
Si
O
O Si
O
O
O
Si O Si O
OO
Si
O
Si
O
O
O
O
Si...
Glenn Research Center at Lewis Field
Titanium Oxide Aerogels: Chemistry
Catalyst: HCl
Glenn Research Center at Lewis Field
Overall Process for Preparing
Transition Metal Oxide Aerogels
aged gel
Native Silica ...
Glenn Research Center at Lewis Field
Metal Oxide Aerogels: Transition Metals
(in ethanol) (age for 72 hrs)
MClx
.
6H2O MOx...
Glenn Research Center at Lewis Field
supercritical
drying (CO2)
Overall Process for Preparing
Transition Metal Oxide Aerog...
Glenn Research Center at Lewis Field
Transition Metal Aerogels: Structure
YOx GdOx ErOx
YbOx FeOx RuOx
Glenn Research Center at Lewis Field
Characterization of Rare-Earth Aerogels
MOx
Density
(g/cc)
Skeletal
Density
(g/cc)
Su...
Glenn Research Center at Lewis Field
Absorbance and Photoluminescence of EuOx
0.5
1
1.5
2
2.5
3
3.5
4
4.5
300 1300 2300
wa...
Glenn Research Center at Lewis Field
Iron Oxide Aerogel
Low Density Magnetic Material
Native
Aerogel
Crosslinked
with di-i...
Glenn Research Center at Lewis Field
Process to Crosslink Metal Oxide Aerogels
supercritical
drying (CO2)
MOx gel
Pour int...
Glenn Research Center at Lewis Field
Crosslinking Chemistries: Polyurethane
Si-OH OCN R NCO+ Si-O C
O
N
H
R NCO
Si-O C
O
N...
Glenn Research Center at Lewis Field
Additional Crosslinking Chemistries
NH
N
H
NH
O
O
O O
O
O
O
O
O
O
O
O
O
O
O
NH2
NH2
N...
Glenn Research Center at Lewis Field
Silicon Dioxide Aerogels Crosslinked with Di-isocyanate
(Bayer’s Desmodur N3200)
Nati...
Glenn Research Center at Lewis Field
Vanadium Oxide Aerogel Crosslinked with a Di-
Isocyanate (Bayer’s Desmodur N3200)
Nat...
Glenn Research Center at Lewis Field
Results and Conclusions
• The following Rare-Earth Gels were prepared:
From all these...
Glenn Research Center at Lewis Field
Acknowledgements
• Plousia Vassilaras (LERCIP)
• Anna Palczer (GRC)
• Linda McCorkle ...
of 22

NASA Glenn Research

Published on: Mar 3, 2016
Source: www.slideshare.net


Transcripts - NASA Glenn Research

  • 1. Glenn Research Center at Lewis Field NANO-CASTED METAL OXIDE AEROGELS AS DUAL PURPOSE STRUCTURAL COMPONENTS FOR SPACE EXPLORATION Eve F. Fabrizio, Ph.D. NASA Glenn Research Center Materials Division/Polymer Branch Brookpark, OH 2003-2004
  • 2. Glenn Research Center at Lewis Field Motivation For Research Conductive Magnetic Light Emitters •Electrical Conduits •Sensors Ultralightweight Strong Structural components Dual Purpose Materials Metal Oxide Nano-casted Aerogels
  • 3. Glenn Research Center at Lewis Field Overview • Preparation of Metal Oxide Aerogels: – Overall process and chemical reactions • Characterization – IR: Hydroxyl content vs. Carbonate content – TGA: Thermal Stability, Phase Transitions – DSC: Phase Transitions – UV-VIS and Photoluminescence – Surface Analysis: Area – Skeletal Density • Crosslinking Chemistries
  • 4. Glenn Research Center at Lewis Field Aerogels nonporous primary particles (<1 nm; dense silica) mesopores channels to micropores porous secondary particles (density ~ 1/2 silica) ~5-10 nm • Properties – Low density (0.05- 0.5 g/cc) – High porosity – High surface area (300-1000 m2/g) • Uses – Poor thermal conductors; Good insulators (see picture) – Good electrical insulators; SiO2-low dielectric <2 – Good electrical conductors; RuOx, VOx – Photophysical properties; optics – Sensors; Optical, Magnetic and Electronic – Catalysts; High surface area increases efficiency of reactions Scanning Electron Microscopy Silicon Dioxide Aerogel
  • 5. Glenn Research Center at Lewis Field MOx Aerogels Prepared Gelled and Tested Attempted; No Gellation Rare-Earth Aerogels: Focus of this Study
  • 6. Glenn Research Center at Lewis Field Silicon Dioxide Aerogels: Chemistry Note: Same chemistry was used to prepare vanadium oxide aerogels.
  • 7. Glenn Research Center at Lewis Field Silicon Dioxide Aerogels: Structure O Si O O Si O O O Si O Si O OO Si O Si O O O O Si HO Si HO Si HO OH OH OH OH Si OH Si OH Si HO HO HO O O O O particle particle interparticle neck-zone N C O N C O H[-O(CH2)4O2C(CH2)4CO- ]n(CH2)3CH2O-H poly(1,4-butylene adipate), diol end-capped N O O Structure of Silica: Polyurethane chemistry: carbamate polyurethane Desmodur N-3200 poly(hexamethylene diisocyanate)
  • 8. Glenn Research Center at Lewis Field Titanium Oxide Aerogels: Chemistry Catalyst: HCl
  • 9. Glenn Research Center at Lewis Field Overall Process for Preparing Transition Metal Oxide Aerogels aged gel Native Silica Aerogels Silica / di-ISO Composites MeOH / Water NH OH sol 15 min gel aging (48 h) gel aged gel washed with EtOH and then acetone several wash cycles (2 days) supercritical drying (CO ) Native silica aerogel monolith sol gel oven (100 deg. C, 3 days) supercritical drying (CO ) di_ISO cross-linked silica aerogel monolith gel washed with EtOH then propylene carbonate di-ISO in propylene cabonate (4 washings) 4 2 2 TMOS in MeOH MeOH / Water NH OH4 4 washings with acetone
  • 10. Glenn Research Center at Lewis Field Metal Oxide Aerogels: Transition Metals (in ethanol) (age for 72 hrs) MClx . 6H2O MOx O Cl a) M O HH O Cl M O H O Cl H + + b) O Cl H M Cl M OH ClHO + +
  • 11. Glenn Research Center at Lewis Field supercritical drying (CO2) Overall Process for Preparing Transition Metal Oxide Aerogels MClX · 6 H2O in CH3CH2OH O Cl MOx Gel Pour into molds and Aged for 72 h Gels washed 4 times with CH3CH2OH Gels washed 4 times with CH3CN Characterization IR,TGA,DSC,Density Surface Area
  • 12. Glenn Research Center at Lewis Field Transition Metal Aerogels: Structure YOx GdOx ErOx YbOx FeOx RuOx
  • 13. Glenn Research Center at Lewis Field Characterization of Rare-Earth Aerogels MOx Density (g/cc) Skeletal Density (g/cc) Surface Area (m2/g) Average Pore Diameter (A) labs,max (nm) lex,max (nm) Magnetic Susceptibility PrOx 0.18 2.82 186 84 (< 300) None N/A NdOx 0.19 3.13 384 109 582 None N/A SmOx 0.22 2.97 383 93 (<300) None N/A EuOx 0.20 2.47 379 77 394 616 N/A GdOx 0.18 3.14 383 72 (<300) None N/A TbOx 0.20 3.32 365 88 (<300) None N/A DyOx 0.18 3.02 N/A N/A (<300) None N/A HoOx 0.21 2.47 N/A N/A 451.5 None N/A ErOx 0.16 3.28 368 89 520/523 None N/A TmOx 0.14 3.17 N/A N/A (<300) None N/A YbOx 0.15 3.25 345 79 291.5 None N/A SiO2 0.18 1.77 500-1000 14 None None N/A
  • 14. Glenn Research Center at Lewis Field Absorbance and Photoluminescence of EuOx 0.5 1 1.5 2 2.5 3 3.5 4 4.5 300 1300 2300 wavelength (nm) absorbance 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 470 570 670 wavelength (nm) emissionintensity lex. = 394 nmabsorbance transistion used for excitation
  • 15. Glenn Research Center at Lewis Field Iron Oxide Aerogel Low Density Magnetic Material Native Aerogel Crosslinked with di-isocyanate Crosslinked aerogel sinter until magnetic
  • 16. Glenn Research Center at Lewis Field Process to Crosslink Metal Oxide Aerogels supercritical drying (CO2) MOx gel Pour into molds and aged for 72 h (Amine modified gels were prepared with aminopropylsilane and No base catalyst) Gels extracted from mold and washed 4 times with solvent for cross-linking Gels placed in monomer solution and crosslinked: D or Initiator Gels washed 4 times with solvent for supercritical drying: Acetone or Acetonitrile Characterization of final gel; physical, chemical and spectral
  • 17. Glenn Research Center at Lewis Field Crosslinking Chemistries: Polyurethane Si-OH OCN R NCO+ Si-O C O N H R NCO Si-O C O N H R NCO H2O Si-O C O N H R NH2 Si-O C O N H R NH2 OCN R NCO+ Si-O C O N H R N H C O N H R NCO adsorbed on silica + CO2 carbamate urea + H2O, etc. silica
  • 18. Glenn Research Center at Lewis Field Additional Crosslinking Chemistries NH N H NH O O O O O O O O O O O O O O O NH2 NH2 NH2 O O O O Secondary particle NH N H NH O O O O O O O O O O O O O O O NH2 NH2 NH2 O O O O NH N H NH O O O O O O O O O O O O O O O NH2 NH2 NH2 O O O O NHNH N H N H NHNH O O O O O O O O O O O O O O O NH2NH2 NH2NH2 NH2NH2 O O O O Secondary particle 2 Si-(CH2)3-NH + n  Si-(CH2)3-NH NH-(CH2)3-Si n-1 AIBN DH Polystyrene linkage 2 Si-(CH2)3-NH + n  Si-(CH2)3-NH NH-(CH2)3-Si n-1 AIBN DH 2 Si-(CH2)3-NH + n  Si-(CH2)3-NH NH-(CH2)3-Si n-1 AIBN DH Polystyrene linkage Epoxies Polystyrene Si-(CH2)3-NH2 +  Si-(CH2)3-NH Aminopropyl groupSecondary particle Cl Styrene Si-(CH2)3-NH2 +  Si-(CH2)3-NH Aminopropyl groupSecondary particle Cl Styrene Cl StyreneStyrene
  • 19. Glenn Research Center at Lewis Field Silicon Dioxide Aerogels Crosslinked with Di-isocyanate (Bayer’s Desmodur N3200) Native Aerogel Native Aerogel Cross-linked Aerogel
  • 20. Glenn Research Center at Lewis Field Vanadium Oxide Aerogel Crosslinked with a Di- Isocyanate (Bayer’s Desmodur N3200) Native gel Crosslinked VOx Aerogel
  • 21. Glenn Research Center at Lewis Field Results and Conclusions • The following Rare-Earth Gels were prepared: From all these metals, two were unsuccessful La- very fragile (unable to remove from mold) Ce-precipitated prior to gelling • For most, structure similar to the silica aerogels with some differences: – more macroporous than microporous – skeletal density greater and pore diameter higher • Analysis by IR,TGA and DSC determined the presence of carbonate in the native rare earth gels. • Carbonate formed during the supercritical drying: impact on crosslinking to be determined • All gels were successfully crosslinked using di-isocyanate and are presently being characterized for chemical, physical and structural properties. Tb HoDyPr Nd Sm Eu Gd Er TmYb LuLa Ce
  • 22. Glenn Research Center at Lewis Field Acknowledgements • Plousia Vassilaras (LERCIP) • Anna Palczer (GRC) • Linda McCorkle and Faysal Ilhan, Ph. D. (OAI) • Nicholas Leventis, Ph.D. (GRC) • Ohio Aerospace Institute (OAI) • Polymer Branch/NASA Glenn Research CenterDemonstration of the insulating properties of aerogels

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