INORGANIC FIBERS AND MATERIALS OF CARBON
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Transcript of INORGANIC FIBERS AND MATERIALS OF CARBON
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1. What are fibres?
2. Classification of Fibres
3. Preparation of Inorganic Fibres
4. Properties of Inorganic Fibres
5. Examples of Inorganic Fibres
6. Applications of Inorganic Fibres
7. Future Perspectives of Inorganic Fibres
Contents (Inorganic Fibres)
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Material that has a length-to-diameter ratio of at least
10:1, with a cross-sectional area of less than 0.005 mm2 and a
thickness of less than 0.25 mm
1. What are fibres?
Fibers, 11. Inorganic Fibers, Survey BERND CLAUB, ITCF Denkendorf, Denkendorf,
Germany ERICH FITZER,
A 6 μm diameter carbon filament
(running from bottom left to top right)
compared to a human hair.
The man made fibres, derived from Inorganic
Substance is called Inorganic Fibres. Glass, Carbon, Ceramics,
and Metal are the examples of Inorganic Fibres.
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Fig.1. Classification of fibres
Naheed Saba Polymers 2014, 6(8), 2247-2273; doi: 10.3390/polym6082247
2. Classification of Fibres
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BORON FIBERS
2BCl3 + 3H2 2B + 6HCl
Produced by Chemical Vapor Deposition Method
Tungsten is used as substrate, D = 8 սm
Temperature 1550 K
Proportion of H2 and BCl3 in reactor is low
Unchanged gases are recycled.
Boron fibre ~ 150 սm
SiC/B4C coating ~ 4սm thick
Retains tensile strength at high temperature
A measurement of the force required
to pull something such as rope, wire,
or a structural beam to the point
where it breaks.
Fig.2. Schematic representation of the assembly used for
the manufacture of boron fibres by CVD using a tungsten
substrate.
3. Preparation of Inorganic Fibres
Inorganic Chemistry P.954, by
Catherine E. Housecraft and
Alan G. Sharpe Third Edition 6
CARBON FIBRES
Different grades of carbon fibre are manufactured by the thermal degradation
of a polymeric organic three carbon-containing precursors:
1. Rayon
2. Pitch
3. Polyacrylonitrile (PAN)
Rayon fibres 500–700 K
AirProduct
1300 K
No Air/N2
H2O, CO, CO2 and CH4
Graphite-like structure (Carbon Fibres)
Low density 1.7 g cm-3
Low tensile
Such fibres have limited uses and are not suitable for structural applications.
Preparation from Rayon
Inorganic Chemistry P.954, 955 by Catherine E. Housecraft and Alan G. Sharpe Third Edition
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Residue left after distillation of crude petroleum or coal tar
High carbon content and cheap starting material
Consists of a mixture of high molecular mass aromatic
and cyclic aliphatic hydrocarbons
Often carry long aliphatic chains
Preparation from Pitch
Pitches750 K
Mesophase
A liquid crystalline material
Melt-spun
Thermosetting/Carbonized
1300 K CO2, H2O, CO, CH4
(Not in order) Graphene Sheets
(In order) Graphite like Structure
S and N impurities are also removed in the form of SOx and NOx.
Melt-spinning involves heating the polymer until molten and
forcing the melt through an appropriately sized aperture. Fig.4. Graphene Sheets
Fig.3. Aromatic Molecules of Pitch
Inorganic Chemistry P.953, 955 by Catherine E. Housecraft and Alan G. Sharpe Third Edition
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Melt
Spin
Petroleum
PitchThermoset Carbonize Graphitize
Surface TreatmentEpoxy SizingSpool
Fig.5. Schematic of pitch based carbon fibre manufacturing procedure
R. Bunsell, Fibre Reinforcements for Composite Materials, Amsterdam, The
Netherlands: Elsevier Science Publishers B.V., 1988, pp 73-210.9
Preparation from Polyacrylonitrile
Fig.6. Polyacryonitrile based Carbon Fibres
1. Polymerization of acrylonitrile to PAN
2. Cyclization during low temperature process
3. High temperature oxidative treatment of
carbonization (Hydrogen is removed).
4. After this, process of graphitization starts
where nitrogen is removed and chains are
joined into graphite planes.
Polyacryonitrile
Fig.7. Synthesis of carbon fiber from
polyacrylonitrile (PAN)
https://en.wikipedia.org/wiki/Carbon_fibers10
PAN Stretch Thermoset Carbonize Graphitize
Spool Epoxy Sizing Surface Treatment
Fig.7. Schematic of PAN based carbon fibre manufacturing procedure
R. Bunsell, Fibre Reinforcements for Composite Materials, Amsterdam, The
Netherlands: Elsevier Science Publishers B.V., 1988, pp 73-210.11
SILICON CARBID FIBERS
nMe2SiCl2 (Me2Si)n
nMe2SiCl2 cyclo-(Me2Si)6
Na
Li
cyclo-(Me2Si)n
(Me2Si)n Me H
Si
CH2
Melt Spinning
Polycarbosilane fibre
Cross-linked fibres with
SiO2 coating
β–SiC fibre
(D = ~20 mm)
Heat in air
(D = ~ 15 mm)
720 K
>1800 K
Inorganic Chemistry P.953, 955 by Catherine E. Housecraft and Alan G. Sharpe Third Edition
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1. Transport reactants via forced convection to reaction region
2. Transport reactants via diffusion to wafer surface
3. Adsorb reactants on surface
4. Surface processes: chemical decomposition, surface migration, site
incorporation, etc.
5. Desorption from surface
6. Transport byproducts through boundary layer
7. Transport byproducts away from deposition region
Steps in Chemical Vapor Deposition Method
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Fig.8. Structure modification during heat treatment
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Fig.9. Stages with respect to temperature
Prof. Dr. Erich Fitzer,
Volume 43, Issue 16,
pages 923–931, August 1971
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PROPERTIES OF FIBERS
High fiber length to width ratio
Tenacity (adequate strength)
Flexibility
Cohesiveness or spinning pliability
Uniformity.
Fiber morphology
Specific gravity
Elongation and elastic recovery
Resiliency
Flammability and other thermal reactions
Electrical conductivity
Abrasion resistance
Chemical reactivity and resistance
Sensitivity to environmental conditions.
Carbon-carbon composites are excellent thermal and mechanical properties
Low density
High strength, toughness and stiffness
Thermal shock resistance due to high thermal conductivity
Low thermal expansion are maintained up to very high temperature (~ 2000 C).
Ablation performance and friction resistance.
Protection for atmosphere re-entry, and for disc brakes of aircraft16
Glass fibres Bosalt Fibres Carbon Fibres
Ceramic FibresAsbestos Fibres
http://textileapex.blogspot.com.br/
EXAMPLES OF INORGANIC FIBRES
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Cotton is used for making jeans, t-shirts and towels
Linen is used for summer clothing, towels and tablecloths
Wool is used for jumpers, suits and blankets
Silk is used for evening wear and ties
Rayon is used for shirts, dresses
Polyester is used for raincoats, fleece jackets, children's nightwear,
medical textiles and working clothes.
Nylon is used for active sportswear, fleece jackets, socks and seat belts.
Acrylic is used for jumpers, fleece jackets and blankets.
Lycra is used for swimwear, exercise gear and stockings.
APPLICATIONS OF INORGANIC FIBRES
Fleece jacketsJumpersExercise gear
Rayon Made
Thread
Rayon Made Rope
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Carbon fibres usually require a protective coating to provide resistance to
reaction with other elements at elevated temperature.
The importance of carbon fibre composite materials in the development of
the space shuttle cannot be ignored.
Reinforced carbon–carbon composites are used in the nose cone and wing
leading edges to provide the resistance to thermal shock and stress required
for re-entry into the Earth’s atmosphere.
Nose Cone
Wing Leading Edges
Typical Structure of a Car Tire
Space Rocket19
Fig. Use of composite materials in Airbus A320 commercial airplane
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The Future is … Fibre by MRIT University P.5-9
The Fibres Wheel – Potential Future Fibres Applications
FUTURE PERSPECTIVES OF INORGANIC FIBRES
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1. What are material of carbon?
2. Nobel Laureates
3. Preparation of Carbon Materials
4. Properties of Carbon Materials
5. Applications of Carbon Materials
6. Future Perspectives of Carbon Materials
Contents Part-2
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Chemical substances containing carbon are called materials of carbon, e.g., carbon
nanotubes, fullerene, graphene.
Fullerene Nanotube Graphene
N. Saifuddin Journal of Chemistry, Volume 2013 (2013), Article ID 676815, 18 pages
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University of Manchester
Adhesive Scotch Tape Method (2004)
Amazing properties of graphene
Awarded the Nobel Prize in Physics in 2010 for their studies.
Sir Andre Konstantin GeimSir Konstantin Sergeevich Novoselov
Photos: Wikipedia
Nobel Laureate
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Single-wall nanotubes (SWNTs), diameter =1.4 nm
Multi-wall nanotubes (MWNTs), 2–30 concentric tubes, diameter = 30–50 nm.
Carbon Nanotubes Morphological Types
SWNTsGraphene
Graphene MWNTs
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First macroscopic production of carbon nanotubes, developed by Sumio Lijima in 1991
Two graphite rods are placed in an enclosure act as electrodes, apart 1 mm.
Helium or argon gas
Low pressure (between 50 and 700 mbar)
The anode is moved close to the cathode until an arc appears
Most nanotubes deposit on the cathode
Carbon in the negative electrode sublimates
The yield for this method is up to 30% by weight
Produces both single- and multi-walled nanotubes.
Arc discharge
Cathode
Inert Gas
Depositio
nAnode
Fig.2:http://students.chem.tue.nl/ifp03/sy
nthesis.html26
Fig.2:http://students.chem.tue.nl/ifp03/synthesis.html
1995 Richard E. Smalley and his group used for the first time laser ablation
Intense laser pulses ablate a carbon target heated from 1200 to 4000°C .
some inert gas like helium or argon carriers
After the cooling of the chamber the nanotubes are collected.
Pure carbon produces multi-walled nanotubes
Catalyst like iron, yttrium, sulphur, nickel and molybdenum produces single-
walled carbon nanotubes
Approximately 28% of the carbon anode evaporates.
Yag Lasar Water cooled Cu Collector
Graphite Target
1200 – 4000 °C
Laser Ablation Method
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1. Hydrocarbons (acetylene, ethylene, propylene, methane)
2. Stream of inert gas
3. Catalyst material may be solid, liquid, or gas.
4. Nanotubes as products
Typical temperature range is 500– 1,200 C at atmospheric pressure.
Carbon nanotubes in powder, thin or thick
Parameters for CNT are the atmosphere, carbon source, catalyst, and
temperature.
Low-temperature (600–900C) yields MWNTs
higher temperature (900–1,200C) reaction favours SWNTs
Commonly used catalysts for CNT growth are the transition metals (Fe, Co, Ni)
1 2 3
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Chemical Vapor Deposition Method
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Nanotubes have van der Waals forces.
All the bond are sp2 bonds and are uniquely stronger than those
sp3 bonds..
Carbon nanotubes are stiff, or elastic, as Young’s modulus
is maximum.
Carbon nanotubes have maximum Tensile strength.
Density shows that carbon nanotubes are stronger than steel and
yet much lighter.
Acts as a metal, if hexagons line up straight along the tube’s axis.
Acts as a semiconductor, if the his found in a exagons spiral
along the axis.
Ballistic electric conductance single-walled carbon nanotubes
(SWCNT).
Dissipate heat better and are excellent thermal conductors.
Carbon nanotubes are very stable; they can withstand the attack
of chemicals and resist exposure to a large temperature range.
Specific ligands with functional groups if added, allows them to be
used in sensors.
Properties of Carbon Nanotubes
Metallic
Semiconductor
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Properties of carbon allotropes and other materials
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Applications
Nanomedicine: Used in Targeted Cancer Therapy
Environment : Used as chemical sensors
Energy : Used as supercapacitors, hydrogen storage materials, solar cells
Textiles: Produce waterproof and tear-resistant fabrics
Body armor: CNT fibers are being used as combat jackets, i.e., protection from
bullets.
Concrete: Increases its tensile strength and stop crack.
Polyethylene: Increase the elastic modulus of the polymers by 30 %.
Sports equipment: Golf balls, golf clubs, stronger and lighter tennis rackets, etc.
Bridges: Able to replace steel in suspension bridges.
Flywheels—The high strength/weight ratios of CNTs enable very high rotational
speeds.
Fire protection: Thin layers of buck paper can potentially protect the object from
fire.
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