Enhancement of bending strength, thermal stability and recyclability of carbon-fiber-reinforced thermoplastics by using silica colloids

Many light but strong composite materials are fabricated using carbon fibers, such as carbon-fiber-reinforced thermoplastics (CFRTPs). However, considering the life cycle of carbon fibers, a technique for recycling carbon fibers is required to sustainably manufacture such composites. To develop a technique for recycling highly valuable carbon fibers from CFRTPs by using nylon, heat-resistant silica colloids with sizes of 45.2 nm were synthesized via a sol–gel reaction. The silica colloids were adsorbed onto the carbon fibers via electrodeposition, which enhanced the interfacial properties of the CFRTP and in turn improved its mechanical properties. The fabricated CFRTP showed homogeneous strength because the silica particles acted as spacers between the carbon fibers, which adhered to each other owing to their hydrophobicity in the nylon resin. Additionally, the mechanical properties of CFRTP were maintained above room temperature. When carbon fibers were reclaimed from the CFRTP via heating up to 500 °C in air, the silica colloids deposited on the carbon fibers helped prevent the tensile strength of the fibers from degrading owing to the oxygen in air during the heating process. The present study demonstrated that the silica colloid surface modification enhanced the mechanical properties, thermal stability, and recyclability of CFRTPs. ファイル公開：2021-09-08