New environmentally friendly and recyclable flame retardant carbon fiber composite material
Carbon fiber reinforced composite material (CFRP) is a composite material containing carbon fiber and epoxy resin. It is four times lighter than steel but has ten times higher strength. It is widely used in aerospace, automotive, marine and other industries. CFRP has poor high-temperature performance. It was previously fire-resistant by adding halogen flame retardants, but this flame retardant will produce toxic substances during incineration and recycling, and is banned worldwide. Toxic and safe flame retardants have become the focus of CFRP research.
Recently, the Korea Institute of Science and Technology (KIST) announced that a research team led by the Institute of Advanced Composite Materials has developed flame retardant carbon fiber reinforced plastics (CFRP) using plant-derived tannic acid, and proposed an environmentally friendly recycling method. Jung Yong-chae, principal researcher at the KIST Advanced Composites Institute, tried to improve the mechanical rigidity and flame retardancy of CFRP by using tannic acid, an eco-friendly substance. Tannic acid is firmly combined with carbon fiber and becomes charcoal when burned. The burnt black tannic acid can be used as a barrier to the inflow of external oxygen to achieve flame retardancy. Unlike traditional epoxy resins, epoxy resins made of tannic acid are flame retardant and do not require additives. This also means that no toxic substances will be produced when CFRP is incinerated for recycling. In addition, because the conventional CFRP will reduce the performance of its epoxy resin when burned, so that it cannot be fully recovered, so the research team proposed a new recycling method. By dissolving CFRP in water in a supercritical fluid state (ie, temperature and pressure exceeding a set level), more than 99% of CFRP can be recovered without degrading carbon fiber performance. When the epoxy resin dissolves, it produces a substance called "carbon point", which can be used as an electronic material. Traditional incineration recycling methods burn epoxy resin, leaving only incomplete carbon fibers for recycling, and this new recycling method can recycle all components of the composite material.
Relevant researchers said: "We have created a composite material with a wide range of applications. Compared with traditional carbon fiber reinforced plastics, its flame retardancy, mechanical rigidity and recyclability have been significantly improved. These improved material properties Very important, they determine the wider scope of application of carbon fiber. We will further study the structure of this composite material to improve performance and further expand its scope of application."