Pioneering the carbon fiber frontier: A half-century of industry leadership and the road ahead

Polyacrylonitrile (PAN)-based carbon fibers have been in full-scale industrialization for more than 50 years, during which time it has grown at an annual rate of 10-20% for half a century, a trend that is expected to continue. Throughout this period, the carbon fiber industry has supported the composites industry through a stable global supply and improved fiber quality. Here, we show PAN-based carbon fibers' history and future for this 50-year milestone. The industrialization of carbon fiber began in 1959, when Shindo discovered how to stabilize PAN. The later discovery of comonomers based on the Morita-Baylis-Hilman reaction by Morita in 1966 further enabled industrialization. In addition to the innovativeness of this breakthrough, progress was made in converging technologies which intensified competition and encouraged incremental innovation. In recent years, microstructure control has become increasingly precise: down to the molecular level through incremental innovations, with tensile strength reaching 8.0 GPa and named T1200. Evaluating the carbon fibers' intrinsic strength by the loop method, where evaluation size is reduced to the order of tens of micrometers, shows that the maximum value of T1200 is very high at 18 GPa. This is almost consistent with the value of 19 GPa predicted using molecular dynamics. Even higher strength can be expected by reducing defects. These performance improvements have already contributed toward carbon neutrality in aircraft and wind power generation. PAN-based carbon fibers will continue to be an important material in the future as further performance improvements and increased mass production are realized.