Carbon fiber

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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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

What is Carbon Fiber?

Carbon fiber is composed of carbon atoms bondedtogether to form a long chain. The fibers are extremelystiff, strong, and light, and are used in many processesto create excellent building materials. Carbon fibermaterial comes in a variety of "raw" building-blocks,including yarns, uni-directional, weaves, braids, andseveral others, which are in turn used to createcomposite parts.

Plain Carbon Fiber Weave Carbon Fiber Twill Weave

Structure and properties of cotton fibre

Each carbon filament thread is a bundle of manythousand carbon filaments. A single such filament is a thintube with a diameter of 5–8 micrometers and consistsalmost exclusively of carbon. The earliest generation ofcarbon fibers (e.g. T300, HTA and AS4) had diameters of7–8 micrometers. Later fibers (e.g. IM6 or IM600) havediameters that are approximately 5 micrometers.

The atomic structure of carbon fiber is similar to thatof graphite, consisting of sheets ofcarbon atoms (graphene sheets) arranged in aregular hexagonal pattern. The difference lies in the waythese sheets interlock. Graphite is a crystalline material inwhich the sheets are stacked parallel to one another inregular fashion.

Structure of carbon fibre

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

Applications of carbon fibre Carbon fiber is most notably used to reinforce composite materials,

particularly the class of materials known as carbon fiber or graphitereinforced polymers. Non-polymer materials can also be used as thematrix for carbon fibers. Due to the formation ofmetal carbides and corrosion considerations, carbon has seen limitedsuccess inmetal matrix composite applications. Reinforced carbon-carbon (RCC) consists of carbon fiber-reinforced graphite, and is usedstructurally in high-temperature applications. The fiber also finds usein filtration of high-temperature gases, as an electrode with highsurface area and impeccable corrosion resistance, and as an anti-static component. Molding a thin layer of carbon fibers significantlyimproves fire resistance of polymers or thermoset composites because adense, compact layer of carbon fibers efficiently reflects heat.

The global demand on carbon fiber composites wasvalued at roughly US$10.8 billion in 2009, whichdeclined 8–10% from the previous year. It is expectedto reach US$13.2 billion by 2012 and to increase toUS$18.6 billion by 2015 with an annual growth rate of7% or more. Strongest demands come from aircraft &aerospace, wind energy, as well as from theautomotive industry with optimized resin systems.

Application of carbon fibre

Manufacturers of carbon fibersMajor manufacturers of carbon fibersinclude Hexcel, SGL Carbon, Toho Tenax, ToraIndustries and Zoltek. Manufacturers typically makedifferent grades of fibers for different applications.Higher modulus carbon fibers are typically moreexpensive

Carbon fibre businessThe market has experiencd a good growth in recentyears and there is veryoptimistic growth expectation incoming years. The average growth rate for the last 23years was about 12%. For the last four years, carbonfiber world market is soaring. There is a huge demandfor aerospace and windmill industry. Market analystshave predicted that world market for carbon fiber willreach $12 billion by 2011.

The effect of carbon fibreThermosetting and thermoplastic polymers have been

reinforced with carbon fibres of high strength and elasticmodulus, and their friction and wear properties examined.During dry sliding against steel, randomly oriented choppedfibres reduce both the coefficients of friction and the wear ratesof polymers to levels which are approximately independent ofthe matrix material. Fibre orientation is also important, andminimum wear is obtained when the fibres are normal to thesliding surface. Carbon fibre reinforced polymers are lessabrasive than those containing glass, exhibit lower friction andhave greater moduli of elasticity; the flexural strengths are alsooften greater, and particularly so with polytetrafluoroethylene(PTFE). It is concluded that the carbon fibres reduce the frictionand wear of polymers by preferentially supporting part of theapplied load, and in addition by smoothing the surface of thesteel counterface.

ConclusionA carbon fiber reinforced composite coil spring is provided

which is made from a braid formed of carbon fibersoriented at a preferred angle to the braid axis ofapproximately plus or minus 45 a resin which serves as asubstantially continuous matrix phase. Longitudinalreinforcing fiber may be incorporated into the braid toprevent it from straightening under longitudinal tension.The carbon fiber reinforced composite coil spring is formedby wrapping the braid, impregnated with a non-solidifiedresin, within a groove which extends helically along thesurface of a helical mandrel and solidifying the resinousmatrix material, and then removing the solid compositecoil spring from the helical mandrel.

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