MECHANICAL PROPERTIES OF CARBON NANOTUBE /EPOXY COMPOSITE LAMINATES PROCESSED USING PREPREG METHOD

This study examined the processing and mechanical properties of aligned MWCNT /epoxy lamina and laminates processed using a hot-melt prepreg method. On-axis and off-axis tensile tests (0 degrees, 45 degrees, 90 degrees) of aligned CNT/epoxy lamina specimens were carried out, and the elastic moduli, E-11, E-22, and G(12) were obtained. Fracture surfaces of lamina specimens after tensile testing were observed using a scanning electron microscope (SEM). As a result, pulled-out CNTs without epoxy adhesion were observed at the interface, which suggests the weak interfacial shear/tensile strengths at the interface between CNT and epoxy. CNT/epoxy laminates ([0 degrees/90 degrees]s, [60 degrees/0 degrees/-60 degrees]s, [0 degrees/45 degrees/90 degrees/-45 degrees]s) were successfully fabricated using aligned CNT/epoxy prepreg sheets. The CNT volume fraction was approximately 10%. No visible void and delamination were observed in composite laminates, and the thickness of each layer was almost the same as that of prepreg. The Young's modulus of CNT/epoxy laminates agreed with the theoretical values, which were calculated using classical laminate theory (CLT) and elastic moduli of CNT/epoxy lamina. The failure strain of [0 degrees/90 degrees] s, [60 degrees/0 degrees/-60 degrees]s, and [0 degrees/45 degrees/90 degrees/-45 degrees]s laminates is respectively 0.65%, 0.92%, 0.63%, which are higher than that of 0 degrees composite lamina (0.5%). The result suggests that the failure strain of 0 degrees layer in composite laminates is improved due to other layers.