Preparation and properties of carbon fiber reinforced epoxy resin composites interlaminate-toughened by polyethersulfone ultrafine-fiber non-woven fabric

To improve the compression strength after impact of epoxy-based composites, polyethersulfone (PES) ultrafine-fiber non-woven fabric was fabricated from polyethersulfone-Nylon 6 (PES-PA6) blended fibers using solution-stripping method, which is more suitable for batch preparation. Then the obtained non-woven fabric was applied in the interlaminar toughing of carbon fiber reinforced epoxy resin-based composites. Interlaminar fracture toughness under mode I (G_IC), interlaminar fracture toughness under mode II (G_IIC), compressive strength after impact (CAI) and interlaminar fracture micro-morphology of composites were tested to research the influence of the non-woven fabric on the interlaminar toughness of composites and the corresponding mechanism of interla-minar toughing. The result indicates that after epoxy resin-based composites are interlaminate-toughened with the non-woven fabric, the G_IC value is raised to 312 J/m² from 289 J/m² and G_IIC value is improved to 3649 J/m² from 1391 J/m². Also, the post-impact damage area of tested specimens is reduced from 1050 mm² to 204 mm² after toughing treatment, and the corresponding post-impact compressive strength is increased from 228 MPa to 307 MPa.