Effect of Different Functional Carbon Nanotubes on the Tribological Behaviors of Poly (Furfuryl Alcohol)-Derived Carbon Nanocomposites

Four kinds of functional multiwalled carbon nanotubes (MWNTs) were obtained by chemical grafting with different groups and examined by infrared spectroscopy, thermal gravimetric analysis, and field emission scanning electron microscopy (FESEM). The different functional MWNTs were used to prepare MWNTs/poly (furfuryl alcohol) (PFA) composites, which were further carbonized to obtain corresponding MWNTs/carbon nanocomposites. The effects of functional groups and dispersion of MWNTs used in the nanocomoposites on tribological behaviors of the resultant nanocomposites were investigated using a block-on-ring wear tester under dry friction conditions. The morphologies of worn surfaces of the MWNTs/carbon nanocomposites were also characterized to deduce the main wear mechanism. Results show that the addition of functional MWNTs can obviously decrease the friction coefficient and wear of the nanocomposites under lower sliding speed, and the tribological behaviors evidently depend on the functional degree of MWNTs. However, under higher sliding speed, the variety and amount of the chemical groups on MWNTs did not have much influence on the tribological behavior of the functional MWNTs/carbon nanocomposites. Consequently, the well dispersion of MWNTs in the nanocomposites caused by the functionalization should be the main dominant factor for the better tribological properties of the resultant nanocomposites.