Carbon nanofibers
Researchers at Rice University have developed carbon nanofibers with a high aspect ratio, featuring filaments approximately 150 nanometres in diameter.
Carbon nanofibers (CNFs) offer a balance of strength and conductivity akin to carbon nanotubes, but in a larger and more manageable form. The distinction between CNFs and carbon nanotubes remains a debated topic within the carbon materials industry.
CNFs are cylindrical carbon nanostructures, typically around 150 nanometers in diameter for vapor-grown grades, though variations exist based on production methods. These fibers range in length from a few microns to nearly continuous electrospun mats. The majority of commercial CNFs are vapor-grown (VGCNF) and feature graphitic layers in stacked-cup, fishbone, or ribbon morphologies. This structure results in a high aspect ratio and an edge-rich surface, which facilitates bonding and functionalization more easily than the seamless walls of carbon nanotubes, though at the expense of crystallinity. The boundary between CNFs and multi-walled carbon nanotubes is contested, as some market analysts consider vapor-grown carbon fibers as a type of carbon nanotube due to their structural similarities. This overlap complicates market data analysis, as CNF and CNT figures are often intertwined and cannot be simply aggregated.
The production of carbon nanofibers is concentrated among a few specialized facilities. Resonac, the leading producer, increased its vapor-grown capacity at its Kawasaki plant in Japan to 400 tonnes annually as of October 2023, up from 300 tonnes. Other emerging producers, including those converting CO2 to carbon, and catalog suppliers operate at smaller scales, typically in the tens of tonnes per year. Accurate global market figures are elusive, as CNF market sizes are often conflated with cellulose nanofibrils due to the shared abbreviation, and some analysts include vapor-grown material within the carbon nanotube market, leading to overlapping CNF and CNT data.
For inquiries about carbon nanofibers, including sourcing, applications, or connecting with producers, contact the Advanced Carbons Council.
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Source: Carbon Nanotubes Feed