Preparation And Properties Of Carbon Nanotubes/Epoxy Nanocomposites

Carbon nanotubes (CNTs) possess unique structure and significant advantages,such as excellent mechanical properties, high thermal stability and electricalconductivity. CNTs are considered as the ultimate type for the novel composites withpolymer. Rapid advance in bulk synthesis of carbon nanotubes (CNTs), coupled withtheir remarkable mechanical properties, are positive signs for application in a host ofcomposites materials. In this paper, carbon nanotubes/epoxy nanocomposites were prepared byultrasonication with carbon nanotubes as reinforcements and epoxy as matrx. We dealwith CNTs with nitric acid, prepare CNTs/epoxy nanocomposites by different powerultrasonication, and study on the electric, mechanical and tribological performance ofthe nanocomposites. We also investigate the dispersity of CNTs in epoxy. Pristine CNTs/epoxy nanocomposites were produced by low energyultrasonication, and the mechanical properties were studied. The results show that thetensile strength, the tensile modulus and the tensile strain decrease to some extent.CNTs treated with nitric acid were used to produce CNTs/epoxy nanocomposites,which tensile modulus increase about 78MPa, but the tensile strength and the tensilestrain decrease sharply with the loading increase of the treated CNTs. On the otherhand, the tensile strain of the nanocomposites produced by high energyultrasonication with pristine CNTs and epoxy increase with the enhancement of thepristine CNTs. When the loading of the pristine CNTs is 1 wt%, the tensile strain ofthe nanocomposites enhances about 20%. The tensile modulus of the nanocomposites IIIincreases with the increase in oxidation time of the CNTs. When the CNTs wereoxidized 16 hr, the tensile modulus of the nanocomposites prepared by it increaseabout 342MPa. When using the SWNTs as reinforcement, the tensile strength, tensilemodulus and tensile strain of the nanocomposites decreases entirely. The influences of CNTs loading on the friction and wear behavior of theresulting nanocomposites sliding against AISII 045 steel were investigated on anOptimal-SRV tribotester at ambient condition. It has been shown that, with theincrease of CNTs addition from 1 wt % to 4 wt%, both the friction coefficient and thewear rate of the nanocomposites decreased from 0.60 and 1.11×10-4mg/(N·m) forpure epoxy to 0.22 and 2.22×10-5mg/(N·m) for nanocomposite loading 4 wt% CNTs,respectively. The composites with the same 1 wt% CNTs content prepared by highpower machine exhibited lower friction coefficient than that of the compositesprepared by low power dispersion because of the uniform dispersion of CNTs inepoxy. The wear surface of the epoxy is coarse, while the surface of thenanocomposites with 4 wt% CNTs content is smooth. The conductivity of the nanocomposites increases sharply, when CNTs wasadded to the epoxy. Epoxy can be made conductivity or semi-conductivity with thecontent of CNTs in nanocomposites.