EFFECT OF FUNCTIONALIZATION OF SINGLE WALLED CARBON NANOTUBES ON ANTIWEAR PROPERTIES OF A MINERAL BASE OIL

In this work, single walled carbon nanotubes (SWNT) were synthesized by chemical carbon vapor deposition (CCVD) method and then were carboxylic acid sidewall functionalized (SWNT_f) in order to investigate their tribological behaviors as antiwear additives for mineral base oil (SAE 20). The functional SWNT were examined by TG, UV-vis, RAMAN spectroscopy and X-Ray diffraction. Furthermore, SWNT and functional SWNT were dispersed in a mineral oil by ultrasonication and the tribological behavior of additivated mineral oil was scrutinize by high frequency reciprocating rig (HFRR) test, while the wear tests were run on a Pin on Disk CSM tribometer. The results show that by functionalization of SWNT was improved the hydrophilicity of carbon nanotubes, thereby functional SWNT being able to create more stable bonds on the metallic surface, being a more efficient antiwear additive rather than non functionalized SWNT. Moreover it was found that due to the coverage with functional groups, the stability of the suspension is high and did not precipitate even after few months.