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


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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


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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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INORGANIC FIBERS AND MATERIALS OF CARBON