In the present paper, mechanical properties of the carbon-nano-fiber reinforced plastic are discussed. Two kinds of carbon-nano-fiber are employed for the filler of the composites, namely vapor grown carbon fiber (VGCF) and cups-stacked carbon nanofiber (CNF (CS)). For the matrix of the composites, three kinds of thermoplastic resin are used which are polypropylene (PP), polyamide (PA 12) and poly-ether-ether-ketone (PEEK). 3-point bending test using short beams are executed to obtain the anisotropic properties of the specimens processed by injection molding. Standard tensile tests are executed to evaluate the stress-strain relation, tensile strength and elastic moduli of the composite materials. Furthermore, Mode I fracture toughness of the composite are evaluated using center-notched flexure specimens. These mechanical properties and characteristics for the specimens are compared and discussed in detail, and the fracture aspects are investigated by scanning electron microscope (SEM).
