Joining prepreg composite interfaces with aligned carbon nanotubes

An interlaminar reinforcement using aligned carbon nanotubes (CNTs) is demonstrated for prepreg unidirectional carbon tape composites. Aligned CNTs are grown at high temperature and then transfer-printed to prepreg at room temperature, maintaining CNT alignment in the through-thickness direction. In initial testing, the CNT-modified interface is observed to increase fracture toughness 1.5–2.5X in Mode I, and 3X in Mode II. Both compliant interlayer and bridging are considered as mechanisms of toughening, with evidence of CNT bridging observed in fracture micrographs. Fabrication methods are compatible with existing manufacturing processes and have the potential to enhance the structural and multifunctional properties of advanced composite laminates.