Development of Next-Generation Ultra-Lightweight CNT Fiber-Reinforced Composite Materials

The aerospace mobility sector is a field in which the economic benefit of weight reduction is maximized, and the evolution of its structural materials has proceeded from metals through lightweight alloys to carbon-fiber-reinforced composites. With the anticipated expansion of the 6G and satellite communication markets, industrial demand for ultralight materials is expected to accelerate further. In this study, composites were fabricated using carbon nanotube (CNT) fibers, which offer a specific strength superior to that of conventional carbon fibers, and the property changes associated with the CNT film fabrication process, chemical post-treatment, and composite molding were examined. The CNT fiber-based films produced by our process exhibited substantially improved mechanical and electrical properties compared with nonwoven sheets fabricated by the conventional FCCVD route. This is attributed to the contraction of the fibers in the coagulation bath, which densifies the bundle structure and thereby improves the alignment of the nanocarbon. In addition, appropriate post-treatment and resin impregnation strengthened the interfacial bonding of the CNT films, so that the resulting composites achieved a higher mechanical strength than the films alone. This work secures the core process technologies required to realize high-performance CNT composites. Future work will incorporate maximized synthesis productivity and high-efficiency post-treatment technologies with the aim of developing next-generation ultralight composites having a density of 1.2 g/cm³ or less.