Synergistic effects of carbon nanotubes on the mechanical properties of basalt and carbon fiber-reinforced polyamide 6 hybrid composites

In this study, a new type of carbon nanotube (CNT) and micro fiber (carbon or basalt)-reinforced polyamide 6 hybrid composites were prepared and investigated. Hybrid composites were produced by melt compounding, and specimens were injection molded. Thanks to the proper dispersion of CNT, a remarkable increment in tensile properties was exhibited. The scanning electron microscopy of the fracture surfaces of the tensile-tested materials revealed that during composite preparation the presence of the fibers in the melt facilitated a better dispersion of the CNT, which explains the enhancement in the tensile properties. The deformation components of the materials were also examined at different load levels. The presence of carbon nanotubes decreased residual deformation at every applied load level. Protruding fiber length investigation revealed that improved mechanical properties are not related to fiber-matrix adhesion but to the reinforcing and stress homogenization effect of nanotubes in the matrix.