This document provides information about carbon fiber, including: 1. What carbon fiber is composed of and its structure. 2. The process of forming carbon fiber from precursor materials like polyacrylonitrile through heating without oxygen. 3. Applications of carbon fiber in composites for aircraft, vehicles, and other products due to its strength and light weight. 4. Major manufacturers of carbon fibers and the growing market for carbon fiber composites.

1. Carbon fiber

2. Prepared By : Mazadul Hasan sheshir
ID: 2010000400008
13th Batch (session 2009-2013)
Department : Wet Processing Technology
Email: mazadulhasan@yahoo.com
Blog : www. Textilelab.blogspot.com (visit)
Southeast University
Department Of Textile Engineering
I/A 251,252 Tejgaon Dhaka Bangladesh
Prepared By :
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3. My assignment contains…..
1) What is Carbon Fiber ?
2) Structure and properties of cotton fibre
3) Formation of carbon fibre
4) Applications of carbon fibre
5) Manufacturers of carbon fibers
6) Carbon fibre business
7) The effect of carbon fibre

4. What is Carbon Fiber?
Carbon fiber is composed of carbon atoms bonded
together to form a long chain. The fibers are extremely
stiff, strong, and light, and are used in many processes
to create excellent building materials. Carbon fiber
material comes in a variety of "raw" building-blocks,
including yarns, uni-directional, weaves, braids, and
several others, which are in turn used to create
composite parts.

5. Plain Carbon Fiber Weave Carbon Fiber Twill Weave

6. Structure and properties of cotton
fibre
Each carbon filament thread is a bundle of many
thousand carbon filaments. A single such filament is a thin
tube with a diameter of 5–8 micrometers and consists
almost exclusively of carbon. The earliest generation of
carbon fibers (e.g. T300, HTA and AS4) had diameters of
7–8 micrometers. Later fibers (e.g. IM6 or IM600) have
diameters that are approximately 5 micrometers.
The atomic structure of carbon fiber is similar to that
of graphite, consisting of sheets of
carbon atoms (graphene sheets) arranged in a
regular hexagonal pattern. The difference lies in the way
these sheets interlock. Graphite is a crystalline material in
which the sheets are stacked parallel to one another in
regular fashion.

7. Structure of carbon fibre

8. Formation of carbon fibre
The raw material used to make carbon fiber is called the precursor. About 90%
of the carbon fibers produced are made from polyacrylonitrile (PAN). The
remaining 10% are made from rayon or petroleum pitch. All of these materials
are organic polymers, characterized by long strings of molecules bound
together by carbon atoms. The exact composition of each precursor varies from
one company to another and is generally considered a trade secret. During the
manufacturing process, a variety of gases and liquids are used. Some of these
materials are designed to react with the fiber to achieve a specific effect. Other
materials are designed not to react or to prevent certain reactions with the
fiber. As with the precursors, the exact compositions of many of these process
materials are considered trade secrets. The process for making carbon fibers is
part chemical and part mechanical. The precursor is drawn into long strands or
fibers and then heated to a very high temperature with-out allowing it to come
in contact with oxygen. Without oxygen, the fiber cannot burn. Instead, the
high temperature causes the atoms in the fiber to vibrate violently until most of
the non-carbon atoms are expelled. This process is called carbonization and
leaves a fiber composed of long, tightly inter-locked chains of carbon atoms
with only a few non-carbon atoms remaining.

9. Applications of carbon fibre
 Carbon fiber is most notably used to reinforce composite materials,
particularly the class of materials known as carbon fiber or graphite
reinforced polymers. Non-polymer materials can also be used as the
matrix for carbon fibers. Due to the formation of
metal carbides and corrosion considerations, carbon has seen limited
success inmetal matrix composite applications. Reinforced carbon-
carbon (RCC) consists of carbon fiber-reinforced graphite, and is used
structurally in high-temperature applications. The fiber also finds use
in filtration of high-temperature gases, as an electrode with high
surface area and impeccable corrosion resistance, and as an anti-
static component. Molding a thin layer of carbon fibers significantly
improves fire resistance of polymers or thermoset composites because a
dense, compact layer of carbon fibers efficiently reflects heat.

10. The global demand on carbon fiber composites was
valued at roughly US$10.8 billion in 2009, which
declined 8–10% from the previous year. It is expected
to reach US$13.2 billion by 2012 and to increase to
US$18.6 billion by 2015 with an annual growth rate of
7% or more. Strongest demands come from aircraft &
aerospace, wind energy, as well as from the
automotive industry with optimized resin systems.

11. Application of carbon fibre

12. Manufacturers of carbon fibers
Major manufacturers of carbon fibers
include Hexcel, SGL Carbon, Toho Tenax, Tora
Industries and Zoltek. Manufacturers typically make
different grades of fibers for different applications.
Higher modulus carbon fibers are typically more
expensive

13. Carbon fibre business
The market has experiencd a good growth in recent
years and there is veryoptimistic growth expectation in
coming years. The average growth rate for the last 23
years was about 12%. For the last four years, carbon
fiber world market is soaring. There is a huge demand
for aerospace and windmill industry. Market analysts
have predicted that world market for carbon fiber will
reach $12 billion by 2011.

14. The effect of carbon fibre
Thermosetting and thermoplastic polymers have been
reinforced with carbon fibres of high strength and elastic
modulus, and their friction and wear properties examined.
During dry sliding against steel, randomly oriented chopped
fibres reduce both the coefficients of friction and the wear rates
of polymers to levels which are approximately independent of
the matrix material. Fibre orientation is also important, and
minimum wear is obtained when the fibres are normal to the
sliding surface. Carbon fibre reinforced polymers are less
abrasive than those containing glass, exhibit lower friction and
have greater moduli of elasticity; the flexural strengths are also
often greater, and particularly so with polytetrafluoroethylene
(PTFE). It is concluded that the carbon fibres reduce the friction
and wear of polymers by preferentially supporting part of the
applied load, and in addition by smoothing the surface of the
steel counterface.

15. Conclusion
A carbon fiber reinforced composite coil spring is provided
which is made from a braid formed of carbon fibers
oriented at a preferred angle to the braid axis of
approximately plus or minus 45 a resin which serves as a
substantially continuous matrix phase. Longitudinal
reinforcing fiber may be incorporated into the braid to
prevent it from straightening under longitudinal tension.
The carbon fiber reinforced composite coil spring is formed
by wrapping the braid, impregnated with a non-solidified
resin, within a groove which extends helically along the
surface of a helical mandrel and solidifying the resinous
matrix material, and then removing the solid composite
coil spring from the helical mandrel.

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