Co-deposition of QU with APTES on the carbon fibers to improve interfacial properties for enhanced mechanical properties

The interfacial bond between carbon fibers (CF) and resin matrix determines the mechanical properties of carbon fiber-reinforced composites. Therefore, surface modification of CF to enhance the interfacial bonding between them is essential. In this paper, quercetin (QU) and 3-aminopropyltriethoxysilane (APTES) were used as raw materials to improve the interfacial properties of CF by co-depositing on the CF surface. QU and APTES undergo a Michael addition or Schiff base reaction under alkaline conditions, resulting in the substance with adhesive properties, which can be uniformly coated on the inert surface of CF. Additionally, the coating introduces a large number of amino groups on the CF surface, which promotes the chemical interaction between the CF and the epoxy resin matrix. The interlayer shear strength (ILSS), flexural modulus, and flexural strength of the composites were enhanced after co-deposition. A new idea for green modification of the CF surface was provided.