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Strength Characteristics of SilicaAerogels
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Aerogel Characterization. Porous nanostructure formed of solid silica. High Porosity ... Continue aerogel fabrication. Characterize standard aerogels. Fall Term ... – PowerPoint PPT presentation
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Title: Strength Characteristics of SilicaAerogels
1
Strength Characteristicsof Silica-Aerogels
- Marissa J. Post
- Senior Project
- Spring 2003
- Advisor Professor Ann Anderson
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Presentation Outline
- Goals
- Background
- What are Aerogels?
- Strengthening Aerogels
- Progress
- Results
- Future Work
3
Goals
- Spring Term
- Research strengthening methods
- Fabricate aerogels
- Characterize standard silica-aerogels
- Fall Term
- Apply select strengthening methods
- Compare standard silica-aerogels with
strengthened aerogels
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Aerogel Characterization
- Porous nanostructure formed of solid silica
- High Porosity
- 90 99 air by volume
- Low Density
- 0.003 0.35 g/cm3
- Low Thermal Conductivity
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Aerogel Applications
- Thermal Insulation
- Walls
- Windows
- Aerospace
- Cosmic dust collectors
- Mars Pathfinder
- Absorption
- Packaging
- Clothing
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Aerogel Fabrication
- Solution
- Precursor Chemical TMOS
- Hydrolyzing Agent H2O
- Solvent Methanol
- Catalyst Ammonia
- Sol-gel
- Aerogel
- Supercritical Extraction
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Aerogel Limitations
- Fragile and Brittle
- Low Compressive Strength
- Low Modulus 2 3 MPa
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Strengthening Aerogels
- Fiber Reinforcement
- Aging and Drying
- Composite Aerogels
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Fiber Reinforcement
- Parmanter and Milstein (1998) compared
unreinforced aerogels to fiber reinforced
aerogels - 68 Silica Fibers 3 mm dia, 1.27 cm length
- 20 Alumina Fibers 2-4 mm dia, 1.27 cm length
- 12 Aluminaborosilicate Fibers 8 mm dia, 1.27 cm
length - Mass Percentages 0, 5, 10, and 25
- Densities 40, 50, and 80 kg/m3
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Fiber Reinforcement
- Modulus was the highest for fiber content of 5
and density of 80 kg/m3 - E 34 MPa
- Modulus increased with increasing density
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Aging and Drying
- Parmenter and Milstein (1998) investigated the
aging effects on the compressive strength of
aerogels - Aged one week
- Aged two months
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Aging and Drying
- Trend of higher modulus with two months of aging
- In one case, the modulus increased from 18 MPa to
28 MPa with aging for two months
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Composite Aerogels
- Marliere and Woignier (2001) experimented with
silica soot (aerosil) composite aerogels - Fumed Silica
- Aerosil weight percentage range 0 70
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Composite Aerogels
- Increased weight percentages of aerosil greatly
increased the modulus
- 70 aerosil composite increased modulus
by nearly 10-fold
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First Term Progress
- Fabricating Aerogels
- CO2 Supercritical Drying
- Compression Tester
- Designed and machined
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Fabricating Aerogels
- Autoclave
Chiller
CO2 Tank
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Compression Tester
- 7075 Aluminum
- Linear Bearings
- Precision Shafts
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Compression Test
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Compression Test
- Standard Aerogel Sample
- 10 mm cylinder, 6 mm dia
- Approximately 0.0001 lbs
- Aged one year
- Load 13 lbs
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Future Work
- Summer
- Continue aerogel fabrication
- Characterize standard aerogels
- Fall Term
- Apply select strengthening methods
- Characterize compressive strength, porosity, and
surface area in strengthened aerogels
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Acknowledgements
- Professor Ann Anderson,
- Professor Bucinell,
- Smitesh Bakrania,
- Jason Elbot,
- Jim Howard,
- Roland Pierson
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