and groundnut oils, with emphasis on the effect of a composite chemical additive. The additive formulation

combined with hydrogen peroxide and oleum, applied at varying concentration levels (10%, 20%, 30%, 40%,

and 50% by volume). Key properties evaluated include kinematic viscosity, pour point, flash point, cloud point,

specific gravity, thermal conductivity, acid value, free fatty acid, and saponification value, following established

ASTM standards. Results indicate that increasing the additive concentration enhances the thermal conductivity

of both oils, with sesame oil demonstrating superior thermal performance compared to groundnut oil.

Conversely, groundnut oil exhibits better viscosity characteristics at higher additive concentrations, retaining

greater lubricity, whereas sesame oil’s viscosity decreases with increasing additive levels. Both oils, however,

exhibit declining thermal conductivity and lubricity at elevated temperatures (50–70°C), revealing a significant

lubricants; Viscosity

The development and use of industrial lubricants have undergone substantial changes as a result of the increased

emphasis on environmental sustainability worldwide. Traditional lubricants derived from petroleum are an

effective means of reducing wear and friction in mechanical systems.

However, they present significant environmental challenges due to their potential toxicity and lack of

biodegradability. (Singh & Chauhan, 2021). These challenges have fueled interest in alternative lubricants

derived from renewable resources, particularly vegetable oils. Vegetable oil-based lubricants are becoming more

and more popular due to their high biodegradability, low eco-toxicity, and the potential to reduce overreliance

antioxidants, pour point depressants, anti-wear additives, extreme pressure additives, corrosion inhibitors and

defoamers.

Recent research studies suggest that adding nano-particles and nano-additives to vegetable oils as lubricants can

significantly improve their tribological properties such as friction coefficient and wear rate; significantly

improving the oxidative stability, frictional characteristics, and general durability of these bio-lubricants. (Kumar

& Chauhan, 2023). The use of additives in vegetable oil-based lubricants is still severely limited by issues such

as creating affordable additives, enhancing thermal resistance and oxidative stability, and guaranteeing

compatibility with current systems. Additionally, not enough research has been done on the efficacy of particular

additives under various operating circumstances. More thorough research is therefore required to completely

comprehend the relationships between lubricants based on vegetable oil and the additives that are added to

For a comprehensive analysis of the evaluation of effects of Additives on vegetable oil based lubricants, the

following materials are required :

The composite additive formulation was specifically designed based on the distinct physicochemical roles of

each component. Aluminium oxide (Al₂O₃) nanoparticles were selected for their well-documented ability to form

a protective tribofilm on lubricated surfaces, reducing friction and wear through a mending and polishing

mechanism (Kumar & Chauhan, 2023). Magnesium sulfate heptahydrate (MgSO₄·7H₂O) was incorporated as a

boundary lubricant additive; its layered crystalline structure allows it to shear easily under contact stress, thereby

lowering the coefficient of friction (Singh & Chauhan, 2021). Hydrogen peroxide serves as an oxidative coupling

agent that promotes surface passivation and assists in dispersing the solid particles homogeneously within the

 Oil extractor : used for oil extraction

 Electric scale : used for measuring the weight

 Thermal conductivity meter : used for determining the thermal conductivity of the vegetable based oil

 Rotational viscometer : used to determine viscosity

 Magnetic stirrer

For oil extraction from groundnuts, the seeds were sourced from Garatu market in Minna, Niger State, Nigeria.

The seeds were initially cleaned to remove common contaminants such as sticks, leaves, sand, stones, and

general dirt. Regardless of the extraction method chosen, pretreatment of the oilseeds is essential (Ogunniyi,

2006). The groundnut seeds were then dried in an electric oven at 80°C for 4 hours. After drying, the red coating

of the seeds was removed to expose the endosperm, as the outer coat does not contain oil. This step enhances

the oil extraction efficiency. The peeled groundnut seeds were fed into an expeller screw, where they were

ground, crushed, and pressed to extract the oil as the seeds passed through the machine. The extracted groundnut

oil was collected in a rubber can. During this process, the high friction coefficient generated a significant amount

of heat. The pressure involved in expeller pressing produces heat in the range of 140–210°F (60–99°C).

Following the ASTM D1298 method, the dry empty 50ml density bottle was first weighed and the weight

recorded as W0, then it was filled with water and weighed. The second weight was recorded as W1. The density

bottle was emptied, re-filled with the oil sample and weighed again. This third weight was recorded as W2.

The specific gravity of the oil sample was calculated,

using the relation,

𝑆𝐺 = 𝑊2−𝑊0 (1)

Where,

SG = Specific gravity This experiment was carried out at room temperature.

of specific gravity by the relation

The sample was poured into the test jar to the level mark. The test jar was closed with the cork carrying the high

pour thermometer. The position of the cork and the thermometer were adjusted for the cork to fit tightly. The

thermometer and the jar were coaxial and the thermometer bulb was immersed 3mm below the surface of the

sample. The test jar was then placed in the cooling medium. The sample was cooled at a specified rate and

examined at intervals of 3oC for flow characteristics until the sample showed no movement when the test jar

was in a horizontal position for 5 seconds. The observed reading of the thermometer was recorded, 3

added to the recorded temperature and the result was recorded as the pour point (ASTM D-97). The higher the

density, viscosity and specific gravity of oil, the more its tendency towards reaching its pour point (Ulakpa,

of the cup to observe if the oil would ignite or produce a pop sound. The temperature at which this was observed

was noted. The procedure was repeated twice and the average temperature was taken and recorded as the flash

point.

The ASTM D2500 method was used to carry out this test. The cloud point jar was first filled with the oil sample,

ensuring that it was free of any impurities or air bubbles. The oil sample was preheated slightly above its expected

cloud point, to ensure homogeneity. The test jar was immersed in a cooling bath, ensuring that the liquid level

in the bath was above the oil level in the jar. The bath was then cooled at the rate of 20C per minute, continuously

monitoring the sample as it cooled. The temperature at which a cloud first appeared and persisted even with

gentle stirring was recorded as the cloud point.

Table 2 : Thermal Conductivities (W/

fatty acid content of sesame oil, particularly linoleic acid (~41%), which promotes stronger van der Waals

2023; Singh & Chauhan, 2021). The superior thermal performance of sesame oil relative to groundnut oil across

all additive concentrations is therefore rooted in its distinct fatty acid profile, which enhances nanoparticle

dispersion stability. However, the thermal conductivity of Sesame Oil decreases at higher temperatures,

indicating that higher quantities of additive (32g fine mixture Al

O

+ MgSO

hepta-hydrate and 5ml Oleum,

thoroughly mixed) makes sesame oil a better lubricant, but higher temperatures make sesame oil a poor lubricant,

as shown in figure 2

stable, high-viscosity baseline that is further reinforced by solid particle loading; this contrasts with the sesame

oil behaviour described below, and is consistent with the findings of Ulakpa (2023) for groundnut-derived bio-

lubricants. The retained lubricity of groundnut oil at higher additive concentrations suggests it is better suited

for moderate-load applications where lubricant film thickness is critical. Groundnut oil retains greater lubricity

at higher quantities of additive (32g fine mixture Al

mixed), indicating that, groundnut oil has better lubricity at higher quantities of additive (32g fine mixture Al

O

+ MgSO

hepta-hydrate and 5ml Oleum, thoroughly mixed), but loses its lubricity at elevated temperatures. This

From the values in Table 5 (triplicate measurements; uncertainty ±0.05 mm²/s), the kinematic viscosity of

markedly different from that of groundnut oil and requires mechanistic explanation. Sesame oil has a higher

polyunsaturated fatty acid content (linoleic acid ~41%; oleic acid ~39%) than groundnut oil, resulting in a less

tightly packed molecular structure. When Al₂O₃ and MgSO₄·7H₂O particles are introduced alongside hydrogen

peroxide and oleum, the oxidative action of these reagents may accelerate partial cleavage of unsaturated C=C

bonds, reducing chain length and thereby lowering viscosity (Rios et al., 2022; Zhang & Wang, 2021). This is

consistent with the lower acid value of sesame oil (0.14 mg KOH/g) compared with groundnut oil (0.36 mg

KOH/g), indicating fewer free fatty acids to resist flow. As a result, sesame oil becomes a progressively less

viscous lubricant at higher additive levels, whereas its superior cold-temperature performance (pour point

not previously highlighted for this additive system. The kinematic viscosity of sesame oil decreases with increase

in temperature and additive (32g fine mixture Al

O

+ MgSO

hepta-hydrate and 5ml Oleum, thoroughly mixed),

which means that sesame oil is less viscous and a poorer lubricant at higher quantities of additive (32g fine

mixture Al

O

+ MgSO