Study On Interlaminar Toughening Carbon Fiber/Epoxy Composites With Short Ramie Fiber

Based on carbon fiber/epoxy resin composite lami nate is easy to delaminate,this paper used short ramie fiber to toughen carbon fiber/epoxy composite laminate interlaminar toughness.Then,the interlayer toughening carbon fiber/epoxy composite laminates with short ramie fiber were made.The interlaminar fracture toughness and the mechanical properties of the carbon fiber/epoxy composites with different SRF length,surface density and surf ace KH-550 coupling treatment were investigated.The results indicate that the insert of short ramie fiber significantly improves the carbon fiber/epoxy composites’ mode I and mode II interlaminar fracture toughness（GIC and GIIC）,and the best interlaminar fracture toughness property can be obtained when the length of SRF is 6 mm and the surface density of short ramie fiber is 12 g·m^-2,and the GIC of the composites improve from 497.48 J ·m^-2 to 667.54 J·m^-2,which increase by 34.24%,the GIIC of the composites improve from 508.52 J·m^-2 to 862.11 J·m^-2,which increase by 69.54%.In addition,the KH-550 modified ramie fiber not only make the mechanical properties of the laminates loss,but also a certain degree of improvement.By observing the scanning electron microscopy（SEM）,the toughening mechanism can be deduced: ramie fibers form bridges between the layers,which impedes the propagation of cracks in the interlayer,and the bridging short fibers need to be pulled out from the matrix or splitting,but also absorb the energy in the crack propagation.