Enhancing the fracture toughness of laminated composites through carbon nanotube belt stitching

Abstract The relatively weak interlaminar performance is one of the key factors that limit the light reducing efficiency of utilizing advanced fiber reinforced composites. In this study, unidirectional carbon fiber reinforced plastics laminates were stitched by using ultra-thin continuous carbon nanotube (CNT) belts in the thickness direction, aiming to enhance their interlaminar properties. A series of mechanical tests, including double cantilever beam testing, end notch flexure testing, tensile and bending testing, were implemented to reveal the contribution of CNT belts stitching. It has been found that after CNT belt stitching, the mode I and mode II interlaminar fracture toughness of the laminated composites are enhanced by 62.5% and 94.3%, respectively, which is mainly due to the bridge-connections between CNTs and CNT-resin interface. Meanwhile, CNT belt stitching results in a negligible variation of the tensile and bending performance of laminated composites.