Teijin Group company Toho Tenax has developed two new processes for the production of carbon fiber that when commercialized should slash the amount of energy used in its manufacture
The company has, in a claimed world first, utilized microwave energy to carbonize the polyacrylonitrile (PAN) fiber precursor under atmospheric pressure and realize a carbon fiber with a tensile modulus of 240 GPa or greater and rupture elongation of 1.5% or greater, both equivalent to levels found in industrial products.
The advanced carbonizing process was developed by examining the fiber structure formation process when carbonizing a bundle of between 12,000 and 24,000 pieces of flame-resistant oxidized PAN fibers, and then developing the most appropriate microwave processing method to carbonize this fibrous material. Using direct heating with microwave energy, fibrous material is carbonized continuously without having to maintain a high-temperature oven, thereby saving time and energy.
Toho Tenax has also developed an ultra-fast carbon fiber plasma surface treatment technology that is based on a dry process. The highly simplified process reportedly reduces energy consumption by 50% compared to the conventional carbon fiber production process. In addition, the ultra-fast treatment improves the adhesiveness of the carbon fiber to the matrix resin.
Toho Tenax is now working to commercialize the two technologies for mass production. Carbon fiber applications are expanding beyond aerospace into fields including automobiles, the environment, energy and infrastructure. However, the carbonizing process for carbon fiber manufacture consumes large amounts of energy and generates CO2 emissions, so reductions in these areas are urgently required to facilitate large-scale mass production for automobiles and other applications according to Toho Tenax.