SUPERINSULATING AEROGELS Arriving on the Construction Market · 2014-03-12 · Carbon aerogels...
Transcript of SUPERINSULATING AEROGELS Arriving on the Construction Market · 2014-03-12 · Carbon aerogels...
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SUPERINSULATING AEROGELS
Arriving on the Construction Market
José Paulo Farinha
INSTITUTO SUPERIOR TÉCNICO
CENTRO DE QUÍMICA-FÍSICA MOLECULAR
INSTITUTE OF NANOSCIENCE AND NANOTECHNOLOGY
AEROGELS in the Construction Market
What’s an Aerogel?
Silica aerogel
Properties & Types
Silica aerogel in construction
Windows, Blankets & Renders
Though Aerogels: Hybrid Aerogels Nanocomposites
Flexible Aerogels: Aerogel Blankets
Production & Properties
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What’s an Aerogel?
An aerogel is an open-celled, mesoporous,solid foam that is composed of a network ofinterconnected nanostructures, exhibiting aporosity of no less than 50%.
Most aerogels have 90 to 99.9% porosityand contain mesopores (2 to 50 nm indiameter) as well as micropores (below 2nm in diameter).
• Aerogels are the dry, low-density,porous solid framework of a gel.
• Aerogels (aka, frozen smoke) arethe lowest density solid materialsever produced, with densitiesaround 20g/L (only 15x heavierthan air). Composed of up to99.98vol% air.
• Surface areas of 100-1000m2/g.
Types of Aerogel
Silica aerogel
The most common type
Organic and Carbon AerogelsOrganic aerogels can be made from polymerssuch as formaldehyde resins, polyacrylamides,polyacrylates, polyurethanes, epoxies, etc.
Carbon aerogels obtained by pyrolysis used usedin fast-charging supercapacitors (3200 m2/g).
Metal Oxide AerogelsAlumina, Titania, Zirconia – clear, scattering white/blue (like Silica)Iron oxide - rust red or yellow, opaqueChromia - deep green or deep blue, opaqueVandia - olive green, opaqueNeodymium oxide - purple, clearSamarium oxide - yellow, clearErbium oxide - pink, clear
Semiconductor AerogelsPhotoluminescent aerogels from metal chalcogenide (CdS, PbSe, etc)
Metal Aerogels
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Silica Aerogel Preparation: The Sol-Gel Method
Reactive “silanol” groups
Hydrolysis
acid or basic catalysis
Condensation
Water condensation
Alcohol condensation
Silica Gel Formation (alkoxide technique)
Silica Gel Formation (alkoxide technique)
Silica Aerogel Preparation
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Obtaining an aerogel
Silica Aerogel Preparation
Drying the wet gel (containing solvent, etc)without destroying the pore structure:
• Supercritical drying (usually with CO2)
• Subcritical drying (by solvent exchange)
Control of surface tension to limit damage by capillary stress.
Solvent extraction
Silica Aerogel Properties
Records held by some specially-formulated silica aerogels :
• Lowest density solid (0.0011 g cm-3)
• Lowest optical index of refraction (1.002)
• Lowest thermal conductivity at atmospheric pressure(0.016 W m-1 K-1)
• Lowest speed of sound through a material (70 m s-1)
• Lowest dielectric constant from 3 to 40 GHz (1.008)
Super thermal insulators
Super sound insulators
Not so super mechanical properties…
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Silica Aerogel Insulation
• Insulation of the Mars exploration rovers
• High-temperature systems
• Cryogenics
• Subsea oil pipelines
• Winter clothing
• Construction
Temperature change >110ºC
Silica Aerogel in Construction
• Transparent Window Insulation
• Interior walls
• Exterior walls
• Roof
• Floor Thermal efficiency, noise
reduction and diffused light
(90% transmission).
Broad Art Museum, Michigan State University
Convent of Fra Angelico, Louvain La Neuve
Crocker Museum, Sacramento, CA
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Silica Aerogel in Construction
• Transparent Window Insulation
• Interior walls
• Exterior walls
• Roof
• Floor
Double interior/exterior insulation with9mm aerogel blanket of 400yr old buildingto achieve passive heating status (noheating/cooling required)
Silica Aerogel in Construction
• Transparent Window Insulation
• Interior walls
• Exterior walls
• Roof
• Floor
9mm aerogel blanket replaced50 mm mineral wood insulation
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Silica Aerogel in Construction
• Transparent Window Insulation
• Interior walls
• Exterior walls
• Roof
• Floor 9mm aerogel blanket installed insteadof 4 cm conventional insulation
• Low compressive strength
• High susceptibility to fracture
Super thermal insulators
Super sound insulators
Not so super mechanical properties…
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Super thermal insulators
Super sound insulators
Though Aerogels: Hybrid Aerogels Nanocomposites
AIRSILTEX
Silica LatexAir
Hybrid Aerogels nanocomposites withwater-dispersed polymeric nanoparticles
• Flexible and mechanically strong films
• Used in coatings
Polymer nanoparticles as impact modifiers
Rubberycross-linkedlow Tg core
Trimethoxisilanereactive shell (binds to sílica)
Farinha, J.P.S. et al. Patented: US7737189 2010; BR200607020 2009; JP2008537570 2008; US2008188575 2008; EP1879690 2008; AU2006231371 2006; etc.
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AIRSILTEXLIGHT
STRONG
INSULATOR
Hybrid aerogel nanocomposite with 3 wt% PNP
SEM
Silica aerogel
Stress-strain curves for unidirectional compression.
Farinha, J.P.S. et al, J. Materials Chemistry 2007, 17, 2195; Chemistry of Materials 2007, 19, 2603; Langmuir 2007, 23, 5727
Bicontinuous distribution of particles (D ≈100 nm) and pores (D ≈10 nm).Porosity > 80%.
Mechanical properties of the hybrid aerogel nanocomposite
…BUT NOT FLEXIBLE
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Possible Strategies
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powderInsulation bag
or matrix
Flexible Aerogelinsulator
Flexible fibre
Hybrid aerogelcoating
Hybrid Aerogel
Flexible fibre
Polymernanoparticles
Silicanetwork
Flexible Hybrid Aerogel
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CONDENSATION
Fibre (Process 2)
SUBCRITICALDRYING
HYDROLYSIS
Fibre (Process 1)
GEL AGING WASHING
SILICA
PRECURSOR
SOLUTION
POLYMER
DISPERSION
Preparation
Properties
Thickness: 0.5±0.2 mm
ρenv = 367 ±81 kg m-3
ρsup = 184 ±17 g m-2
K = 8.13 mWm-1K-1
Latex 2%; Glass or polyester fibre 28%
Fiber well coated
Good Flexibility
ρenv in aerogel range
Good thermic insulation
Hydrophobicity
Farinha, J.P.S., J. Materials Chemistry A2013, 1, 12044-12052. PCT patent pending.
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CQFM-IN / IST-UL
Prof. Gaspar Martinho
Prof. Laura Ilharco
Dra Alexandra Fidalgo
Acknowledgments
Interfaces, acrylic on canvas, 1.5 m x 1.5 m
Acknowledgments
Ana Tristany
www.anatristany.com