Carbon Fibre - A Feasible Fibre

 Carbon fiber is a type of fiber that is made from organic polymers consisting of long strings of molecules held together by carbon atoms. Most of the carbon fibers (about 90%) are made from the Polyacrylonitrile (PAN) process, and the rest of the carbon fibers are mainly manufactured from rayon or the Petroleum pitch process. Carbon fibers are about 5 to 10 micrometers(0.00020-0.00039 in) in diameter which is very thin strings. They have high tensile strength and they are extremely strong for their size. In fact, the carbon nanotube, a form of carbon fiber is considered the strongest material available. 

Manufacturing Process : 
Carbon fiber is a result of both chemical and mechanical processes. Precursors, the raw materials of carbon fibers are drawn into long strands and heated to high temperatures in an Anaerobic (Oxygen-free) environment. The extreme heat causes the fiber atoms to vibrate so violently that almost all non-carbon atoms are expelled. 

After the carbonization process, the remaining fiber is made up of long closely interlocked carbon atom chains with few or no non-carbon atoms remaining. These fibers are subsequently woven into fabric or combined with other materials and then the filaments are wound or molded into certain shapes and sizes. 

Typically, the following segments are followed while manufacturing the carbon fiber ( PAN Process)- 

1. Spinning
2. Stabilizing
3. Carbonizing
4. Treating the surface
5. Sizing

Types of carbon fiber:

Based on precursor fiber materials-

1. PAN-based Carbon Fibres 
2. Rayon-based Carbon Fibres
3. Pitch-based Carbon Fibres
4. Mesophase Pitch-based Carbon Fibres
5. Isotropic Pitch-based Carbon Fibres
6. Gas-Phase Grown Carbon Fibres               

Based on final heat treatment temperature- 

1. High heated treatment carbon fibers(HTT)– Temperature should be above 2000 degrees Celsius
2. Intermediate heat treatment carbon fibers(IHT) - Temperature should be around or above 1500 degrees Celsius
3. Low heat treatment carbon fibers(LHT) - Temperature should not be greater than 1000 degrees Celsius

Properties: 

• Carbon fibers are twice as sturdy as is steel And five times as strong as steel( per unit of weight)
• Chemically stable
• Have high-temperature tolerance along with a low thermal expansion
• Corrosion and fatigue resistant
• Electrically conductive
• Have good tensile strength
• Nonflammable (fire-resistant)
• Biologically inert, X-ray permeable

Application: 
Because of its great physical strength, specific toughness, and being light weighed it is used in the aerospace sector in constructions – roads, marine transports, etc And sporting goods it also has good vibration damping, strength, and toughness. Thus, it is also used in many audio types of equipment, Loudspeakers for Hi-Fi types of equipment, etc. Carbon fibers are also used in the Medical sector, Automobiles and Electronics, Textile machinery, Genera engineering, chemical industry nuclear fields, and many more. 

Carbon fiber in manufacturing Lamborghini car (Source: yahoo news)

What is the future of carbon fiber? 
As carbon fiber technology is bringing out more and more amazing features of it, there is a possibility that some new materials of it again also be used in conjunction with commercial-grade 3D printers. MIT Associate professor of Mechanical Engineering, John Hart, a pioneer of the nanotube, has been working on it with his students so that they can transform the technology for manufacturing. Hart also worked with MIT Associate professor of Chemistry Mircea Dinca is a Collaboration with Automobile Lamborghini to investigate the possibilities of new carbon fiber and composite materials with a vision of “lighter stronger bodies more efficient catalytic converters, thinner paint, and improved power-trained heat transfer”. So, it can be said that the carbon fiber industry will reach its vast potential if the manufacturers adopt a cheaper and new technology target NYU application find out the primary competitors of carbon fibers and bring out more revolutionary changes are additions to it. 

References: 

1. Material Science Journal
2. ThoughtCo.

Amatullah Iffat 
Department of Textile Machinery Design & Maintenance, 44th Batch
Bangladesh University of Textiles (BUTEX)