Investigation of the viscoelastic and thermo-physical properties of mineral base engine oils containing multi walled carbon nanotubes

Abstract

It is a known fact now that the commercially available lubricating oils depict lower thermo-physical features when compared with lube oils with antiwar additives. Objective: The thermo-physical and viscoelastic properties such as shear rate, shear stress, viscosity, Torque and ultrasonic velocity of additivated mineral base engine oils were calculated and studied for improvement markers. Method: In the current experimental work, samples were prepared for two different mineral base engine oils of 20W50 grade with one sample each of base fluid and three each with multi walled carbon nanotubes coated with stearic acid (carboxylic acid) added in 0.1 %, 0.3% and 0.5% wt concentration to base sample respectively. The Multi walled carbon nano tubes (MWCNTs) were then dispersed in a mineral oil by ultrasonication. The properties were investigated using a Rheometer (viscoelastic properties), ultrasonic velocity measurements were conducted using nano fluid interferometer and thermal conductivity was recorded using KD2 pro thermal property analyser apparatus. A comparative analysis is given in this paper. Findings: The results show that by functionalization of MWCNTs, the viscoelastic properties of the base mineral oil improved as more stable bonds 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 suspension is high and it does not coagulate. Applications: The applications and benefits are numerous including automobile sector, heavy machinery sector etc. Keywords: Engine Oil Lubricants, Thermo-physical Behaviour, Ultrasonic Velocity, Viscoelasticity