CARBON FIBERS

Carbon fiber is well known textile material. In this graphite crystalline structures are arranged in a manner that it gives fibrous material. Carbon fiber is also available by oil/coal Pitch based carbon fiber, Mesophase pitch based carbon fiber, Isotropic pitch based carbon fiber, PAN – based carbon fiber, Rayon – based carbon fiber and gas – phase – based carbon fibers.

            The structure consists of graphite layer planes highly oriented in the direction of the fiber axis, the more highly oriented, the higher the modulus. The main limitation in developing tensile strength in the past was structural flaw development during the graphitization and the formation of crystalline walls nucleated by the particles. Such inclusions produce large disoriented crystallites that initiate failure. Still higher modulus, however, is obtained by using mesophase pitch as a precursor. This process differs radically from the PAN route.

Physical Properties of Different carbon fiber

Type of Fiber	Precursor Material	Density g/cc	Tenacity GPa (g/d)	Modulus GPa	Breaking Extension (%)
High Strength	PAN	1.7 – 1.8	2.8 – 4.0 (20 – 25)	230 – 250	1.0 – 2.0
Ultra High Strength	PAN	1.7 – 1.8	4.1 – 5.7 (25 – 35)	260 – 290	0.8 – 1.0
Low Modulus	Rayon / Pitch	1.3 – 1.7	0.6 – 1.0 (3 – 5)	40 – 60	2.0 – 5.0
High Modulus	PAN / Mesophase Pitch	1.8 – 2.0	1.7 – 3.5 (5 – 20)	450 – 750	0.5
Ultra High Modulus	Mesophase pitch	2.0 – 2.2	2.1 – 2.4 (8 – 20)	600 – 900	0.2

Carbon Fiber Properties

ð  The fiber does not melt.

ð  It oxidies very slowly in air at temperatures above 330°C.

ð  The fiber exhibits excellent resistance to acids, alkalies even at high concentration and temperature.

ð  It is also inert to all solvents.

ð  Strong oxidizing agents will degrade carbon fiber and it has poor resistance to hydro chlorites.

ð  The fiber cannot be dyed.

Application of Carbon Fiber

ð  Sporting goods, aerospace, marine and road transport

ð  Pickup arms, audio equipment, robot arms, Hi – fi equipment and loud speakers

ð  Medical applications in X – ray and surgery equipment, ligament and tendon repair and in implants

ð  Nuclear field, chemical industry, pumps, seals, valves and its components in process plants

ð  Textile machinery, genera engineering

ð  Radiological equipment

ð  Large generator retaining rings

ð  Novel tooling, brushes, automobile hoods casings and bases for electronic equipments

ð  EMI and RF shielding

ð  Missiles, aircraft brakes, aerospace antenna and support structure

ð  Large telescopes, waveguides for stable high – frequency (GHz) precision measurement frames and optical benches.

Carbon Fiber Manufacturers

ð  Ocean Power Fiber Co, Ltd.

ð  CiXi Aiflon Sealing Materials Co. Ltd.

ð  East Midlands Composites Ltd.

ð  Acordis