**2. Methodology**

Rheological properties, oxidative stability and tribological properties of the PO with and without the addition of suitable additives are studied. Various PO blends with the additives are prepared using a magnetic stirrer. Rheological properties (dynamic viscosity, kinematic viscosity and viscosity index) of the oil blends are evaluated by using a rheometer (Anton Par MCR 102) having parallel plate geometry and redwood viscometer. Oxidation stability of the sample is determined using hot oil oxidation test (HOOT) in a dark oven. Tribological properties viz. wear scar diameter (WSD) and coefficient of friction (COF) are acquired with the help of a four-ball tester apparatus. Worn-out portions of the ball specimens are examined initially using an optical microscope and later by a scanning electron microscope (SEM). Chemical properties of the PO such as total acid number, total base number, iodine value, saponification value are also analyzed as per ASTM Standards (**Table 1**).
