Toughening mechanisms and morphology of composite cylinders interleaved with hybrid nanoparticles

Abstract

Laminated carbon fiber-reinforced plastics (CFRPs) have been applied to complex structures in various industries owing to their excellent physical and mechanical properties. However, the use of such plastics is limited because their through-thickness failure presents an important structural vulnerability. This study aimed to develop an epoxy characterized by excellent interlaminar toughness that could be applied to filament-wound CFRP cylinders. The epoxy was modified with carbon nanotubes (CNTs) and halloysite nanotubes (HNTs), and the toughening effect of these nanomaterials on the CFRP composite was examined. The combination of CNTs and HNTs remarkably enhanced the interlaminar toughness of the epoxy and structurally improved the cohesiveness of individual nanoparticles, resulting in the partial reinforcement of the laminated structure of the CFRP. The reinforcements of the epoxy and interfacial bonding force between the epoxy and carbon fibers were also improved by the hybridization of small amounts of the CNTs and HNTs. In particular, the HNTs significantly improved the through-thickness characteristics of the CFRP by providing strong bridging effects. The interleaved CNT/HNT design developed in this work was suitable for application to hybrid-reinforced laminated CFRPs and may be considered a potential nanomaterial technology that could ensure the stable performance of CFRP-based structures against failure.