LAUSR

In engineering applications, bismaleimide (BMI) carbon fiber composites with interlaminar toughening and self‐healing properties show significant developmental potential. This study focuses on the interlaminar toughening and low‐temperature repeatable self‐healing performance of core‐shell nanofibers. Using coaxial electrospinning technology, core‐shell nanofibers composed of polyacrylonitrile (PAN) and polycaprolactone (PCL) were successfully prepared. This unique nanofiber design features a high‐melting‐point PAN shell that stabilizes the nanofiber morphology within the composite interlayers, providing nanotoughening effects while protecting the core PCL from destabilization. Under external loading, microcracks in the matrix expand and pierce the nanofiber shell. Consequently, the low‐melting‐point PCL core can flow and fill the cracks under thermal stimulation, thus achieving self‐healing effects. The results show that adding core‐shell nanofibers increases the flexural and shear strengths of CF/BMI composites by 7.70% and 10.72%, respectively. The healing performance was evaluated by cyclic three‐point bending tests, and the secondary damage‐repair results were 94.31% and 78.36%, respectively.