Mode II Interlaminar delamination of composite laminates incorporating with polymer ultrathin fibers

This study makes use of electrospinning to produce epoxy polymer ultrathin fibers. Those fibers were collected as nonwoven sheets with various thicknesses. The collected ultrathin fibrous sheets (UFS) were incorporated into ply interfaces of a glass/epoxy composite laminate. End-notch flexure (ENF) specimens were employed to measure the mode II interlaminar fracture toughness (G(IIC)) of the resulting laminate. Scanning electron microscopy (SEM) was carried out to investigate the fracture surface and fracture mechanism of tested samples. Results indicate that there were some reinforcing effects of the UFS on the G(IIC) when the thickness of the sheets was not more than 0.13 mm for a single sheet and 0.06 mm for multi-sheets incorporated. The mechanical properties were quickly decreased and became poorer when a higher thickness of the sheets was used.