If there was ever a superhero of man-made materials, it would be carbon fibre. And if you think you’ve never met carbon fibre, think again. This versatile and common material is used to make airplanes, boats, golf clubs, speakers, missiles, X-ray equipment, wind turbines, bikes, cars, valves, seals, pumps… and it’s even used for surgical repair of tendons and ligaments.
You get the point – carbon fibre is everywhere and it’s prevalent because it’s both lightweight and strong. It’s five times stronger than steel and twice as stiff, but weighs two-thirds less.
How it’s made
Carbon fibre is basically very thin strands of carbon – thinner than a human hair. It’s made of strong crystalline carbon filaments and gets its superhero strength when those filaments are twisted together like yarn, then woven together like cloth. That sheet of carbon can then be laid over a mold and coated in resin or plastic to take on a permanent shape.
Of course, carbon fibre just wouldn’t have its superhero powers without a little help from petroleum.
Carbon fibre is composed of carbon atoms bonded together to form a long chain. Ninety per cent of today’s carbon fibres are made from polyacrylonitrile, which in turn is manufactured from polymers and acrylonitrile – both among the 6,000 useful products that come from petroleum. The remaining 10 per cent of carbon fibres are made from rayon or petroleum pitch.
Shhhhh… it’s a secret
Making carbon fibre is complicated – the process is partly chemical, partly mechanical. Simply put, the original material is drawn into long strands and then heated to a very high temperature in the absence of oxygen so the fibre cannot burn. The high temperature causes the atoms in the fibre to vibrate until most of the non-carbon atoms are expelled. This process is called carbonization and results in a strand of long, tightly interlocked chains of carbon atoms.
During the manufacturing process, a variety of gases and liquids are used. While some of these materials react with the fibre to achieve specific effects, others prevent certain reactions with the fibre, again to give desired results. The precise composition of each carbon fibre material varies from one manufacturer to another and are generally considered to be trade secrets and competitive advantages.
The green side of carbon fibre
One of carbon fibre’s biggest advantages is how light it is compared to many other materials, which can result in lower greenhouse gas emissions. Let’s use a car for example. Many vehicle components are made from steel, but replacing steel components with lighter carbon fibre can reduce the weight of an average car by up to 60 per cent [source: USA Today]. A lighter vehicle burns less fuel – by up to 30 per cent, cutting emissions by 10 to 20 per cent [source: Oak Ridge National Laboratory].
Carbon fibre use is growing. It was always used for small component parts in aircraft, but it is now being used for entire structures such as the fuselage and wings thanks to its lightweight, strong makeup.