Supramolecular network-modified pyrolytically recycled carbon fiber composites with recyclability, shape-memory effects, and flame retardation

With the continuous increase in the use of carbon fiber composites, the composite waste generated during production and application will always have an impact on the environment. By pyrolyzing carbon fiber composites, carbon fibers can be recycled, which is also beneficial for the sustainable development of carbon fiber composites. Compared to commercial carbon fiber (CFs), the performance of recycled carbon fiber (rCFs) is somewhat reduced, and it is generally mainly used as a low value filler. In order to enhance the application value of recycled fibers and broaden their application fields, we developed a simple, eco-friendly modification technique to construct supramolecular networks on the surface of rCFs. Evaluate the application effect of carbon fiber by preparing composite materials with tannic acid cured epoxy resin (TE). In comparison with rCFs composite samples, the supramolecular network modified rCF composites can achieve performance improvements through synergistic non covalent and covalent interface interactions: mechanical strength increased by 27.01 %, shape memory storage entropy energy density increased by 8.95 %, and structural stability was maintained under high temperature conditions. This work provides a new technological approach for the widespread application of recycled carbon fibers.