Enhanced interlaminar fracture toughness of unidirectional CFRP laminates with tailored microstructural heterogeneity of toughening layer

This work detailed a novel hierarchical Carbon fiber/CNT/Epoxy composites with tailored microstructural heterogeneity of toughening layer. The heterogeneity in the toughening layer of these laminates was engineered during spray coating process by controlling the length and content of CNT to produce CNT aggregated particles with spatial separation. Each particle contains a number of CNT and is managed to have controlled sizes. The concept of “CNT particle toughening” was firstly proposed and confirmed, opening a new way to fully enable the exploitation of the toughening potential of CNT. The effectiveness and efficiency of this technique are demonstrated by using the extremely low CNT content (0.3 gsm) to achieve remarkable improvements of the Mode-I and Mode-II interlaminar fracture toughness, which are 168 % and 155 %, respectively.