Inhomogeneous toughening of carbon fiber/epoxy composite using electrospun polysulfone nanofibrous membranes by in situ phase separation

A novel approach for toughening carbon fiber/epoxy composite using electrospun polysulfone (PSF) nanofibrous membranes was performed. As-received membranes were composed of nanofibers with random orientation, and were directly electrospun onto layers of carbon fiber/epoxy prepregs to toughen the composites. According to the random dispersed nanofibers in the membranes, the inhomogeneous phase separation of polysulfone, which was generated in situ along the nanofibers direction during the curing of epoxy matrix, was proposed. Owing to the aligned PSF spheres, excellent mechanical properties of composites were obtained. Mode I interlaminar fracture toughness (GIC) increased 158%, 261% and 281% by loading 1 wt%, 3 wt% and 5 wt% nanofibrous membranes, which was far higher than those of the same content PSF films toughened composites. DMTA tests revealed good compatibility between nanofibrous membranes and epoxy matrix. And the flexural properties increased slightly compared to untoughened composite.