EFFECT OF FUNCTIONALIZATION OF MULTI WALLED CARBON NANOTUBES ON VISCOELASTIC PROPERTIES OF A MINERAL BASE ENGINE OIL

In the current experimental work, multi walled carbon nanotubes (MWCNT) were coated with stearic acid (carboxylic group) in order to investigate their viscoelastic properties as wear reduction additive for a mineral base engine oil (SAE 20W50). The functional MWCNTs were examined by Fourier Transform Infrared Spectroscopy (FTIR) technique, Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM). The MWCNTs were then dispersed in a mineral oil by ultrasonication and viscoelastic properties such as shear rate, shear stress, viscosity, Torque etc of additivated mineral oil was investigated using a Rheometer and ultrasonic velocity measurements were conducted using nano fluid interferometer. The results show that by functionalization of MWCNTs, the viscoelastic properties of the base mineral oil improved as more steady links were created on metallic surface due to improved absorption qualities. It was also deduced that due to coating of MWCNTs with carboxylic group stearic acid, the stability of solution is good and it does not coagulate for normal running cycle.