Grafting of active carbon nanotubes onto carbon fiber using one-pot aryl diazonium reaction for superior interfacial strength in silicone resin composites

A novel and effective method was proposed for grafting carbon nanotubes (CNTs) with amino groups onto the surface of carbon fibers (CFs) by using one-pot aryl diazonium reaction in mild, eco-friendly conditions. Based on the diazonium reaction, CNTs were grafted with phenyl amino groups, and then functionalized CNTs (CNT-NH2) were modified onto the fiber surface to enhance fiber surface roughness and wettability, which could potentially increase interfacial strength of composites. Homogeneous multi-scale structures with different concentrations of CNTs were achieved. Interfacial properties of hybrid composites were closely dependent on the grafting density. The resulting hierarchical reinforcements improved composites interfacial strength significantly by the enhanced mechanical interlocking and the formed chemical bonding at the interface.