**3.1 Preliminary analysis and enhancement of properties of PO**

A series of experiments have been conducted as per standards and results are taken as an average of 3 readings having standard deviation of the sample as the error bar. The experimental data are given in the graphs and tables. **Table 2** represents the physicochemical properties of PO and compared with two widely studied bases stock viz. sesame oil and coconut oil.

The density of PO is found to be 0.92 g/cm3 using a pycnometer, which is lower than that of water. It is found that the acid number of PO is slightly higher than that of the sesame oil and coconut oil. However, for lubricant TAN value should be low as possible [15]. PO has the least saponification value among the three. Low SV indicates long fatty acid chain, which helps in the formation of thick tribolayer [16]. Iodine value of a triglyceride indirectly shows the amount of unsaturation present in it [17]. From the iodine value, it is clear that unsaturation in PO lies between sesame oil and coconut oil. Thus, it is clear from the evaluation of physicochemical

**207**

**Figure 2.** *TGA of PO.*

**Figure 1.**

*Biolubricant from Pongamia Oil*

5 Density (g/cm3

friendly lubricant.

**Table 2.**

*DOI: http://dx.doi.org/10.5772/intechopen.93477*

*Physiochemical properties of PO, sesame oil, and coconut oil.*

properties of PO that most of the chemical properties are well suited to the desirable properties of a base stock, which can lead to the development of an eco-

can be reduced using a suitable pour point depressant.

*Differential scanning calorimetry* **(***DSC) curve of PO.*

The temperature below which the liquid loses its flow characteristics is known as pour point of a liquid [18]. **Figure 1** represents the pour point of PO, which is evaluated from differential scanning calorimetry (DSC). The pour point of PO was found as 6.29°C. The pour point of PO is found to be lower than that of coconut oil [9] due to the presence of more unsaturated fatty acids. Pour point of the lubricants

**Sl. no Analysis Pongamia oil Sesame oil [9] Coconut oil [9]** Iodine value (g I2/100 g) 88.18 ± 0.19 105.1 9 Saponification value (mg KOH/g) 168.75 ± 3.72 191 261 Total acid number (mg KOH/g) 3.94 ± 0.14 3.18 0.56 Total base number (mg KOH/g) 0.37 ± 0.01 0.41 0.16

) 0.92 0.9216 0.92429

The thermal stability of PO is studied using TGA [19]. From the TGA results (**Figure 2**), the onset temperature of PO for thermal degradation of 98% is found out as 197.6°C. The weight percentage reduction 2% of PO was done by assuming


**Table 2.**

*Tribology in Materials and Manufacturing - Wear, Friction and Lubrication*

while maintaining a unit distance apart in the fluid.

Redwood viscometer for PO from 40–100°C.

diameter is recorded.

oxidation stability.

**3. Results**

d.*IODINE VALUE:* The iodine value (or iodine adsorption value or iodine number or iodine index) is the mass of iodine in grams that is consumed by 100 g of a chemical substance. Iodine numbers are used to find the quantity of unsaturation in fatty acids. ASTM D1959 standard was used for calculations.

e.*DYNAMIC VISCOSITY ANALYSIS:* The dynamic viscosity is measured using Anton Par Rheometer MCR 102 in rotation mode having parallel plate geometry. Dynamic (absolute) viscosity is the tangential force per unit area required to move one horizontal plane with respect to another plane, at a unit velocity,

f. *KINEMATIC VISCOSITY ANALYSIS:* Kinematic viscosity is the ratio of absolute (or dynamic) viscosity to density. Force is not involved in this quantity. Kinematic viscosity can be found out by dividing the absolute viscosity of a fluid with the fluid mass density. The kinematic viscosity is measured using

g.*WEAR SCAR DIAMETER ANALYSIS:* Four ball testing of the oil is done in a four ball tester apparatus, with the sample, given a load of 40 kg at 75°C. The ball is then analyzed using a scanning electron microscope and wear scar

h.*COEFFICIENT OF FRICTION ANALYSIS:* Four ball testing of the oil is done in a four ball tester apparatus, with the sample, given a load of 40 kg at 75°C.

i. *HOT OIL OXIDATION TEST:* The quickened aging of vegetable oil and PO added with antioxidant are stimulated with HOOT. This is done to find the

j. *THERMOGRAVIMETRIC ANALYSIS:* The thermal stability of antioxidant selected and that of the formulated oil (FO) are evaluated using the thermoanalytical curves obtained from TGA, Q50 equipment, TA-Instruments.

A series of experiments have been conducted as per standards and results are taken as an average of 3 readings having standard deviation of the sample as the error bar. The experimental data are given in the graphs and tables. **Table 2** represents the physicochemical properties of PO and compared with two widely studied

than that of water. It is found that the acid number of PO is slightly higher than that of the sesame oil and coconut oil. However, for lubricant TAN value should be low as possible [15]. PO has the least saponification value among the three. Low SV indicates long fatty acid chain, which helps in the formation of thick tribolayer [16]. Iodine value of a triglyceride indirectly shows the amount of unsaturation present in it [17]. From the iodine value, it is clear that unsaturation in PO lies between sesame oil and coconut oil. Thus, it is clear from the evaluation of physicochemical

using a pycnometer, which is lower

**3.1 Preliminary analysis and enhancement of properties of PO**

bases stock viz. sesame oil and coconut oil. The density of PO is found to be 0.92 g/cm3

Calculations were done as per ASTM D 5183-05 standard to test COF.

**206**

*Physiochemical properties of PO, sesame oil, and coconut oil.*

properties of PO that most of the chemical properties are well suited to the desirable properties of a base stock, which can lead to the development of an ecofriendly lubricant.

The temperature below which the liquid loses its flow characteristics is known as pour point of a liquid [18]. **Figure 1** represents the pour point of PO, which is evaluated from differential scanning calorimetry (DSC). The pour point of PO was found as 6.29°C. The pour point of PO is found to be lower than that of coconut oil [9] due to the presence of more unsaturated fatty acids. Pour point of the lubricants can be reduced using a suitable pour point depressant.

The thermal stability of PO is studied using TGA [19]. From the TGA results (**Figure 2**), the onset temperature of PO for thermal degradation of 98% is found out as 197.6°C. The weight percentage reduction 2% of PO was done by assuming

**Figure 1.** *Differential scanning calorimetry* **(***DSC) curve of PO.*

**Figure 2.** *TGA of PO.*

the loss of moisture content and volatile components from it [19]. Thus, by observing the TGA, it is evident that PO is a well suited environment-friendly base stock for a wide range of temperatures. The thermal compared to SAE20W40 which have thermal degradation of at 204.39°C [9].

**Table 3** shows the fatty acid profile of PO, compared with that of sesame oil and coconut oil. High amount of oleic acid present in the PO can improve the tribological properties [10]. A larger proportion of saturated fatty acids can adversely affect the pour point of the lubricants.
