PHYSICAL-MECHANICAL, VISCOMETRIC, AND IR-SPECTROSCOPIC ANALYSIS OF A NEW OINTMENT PREPARED BASED ON MAHSAR OIL

ABSTRACT

A new lubricating oil synthesized based on Mahsar oil, grill oil, thiourea, polycrotonaldehyde, and calcium stearate was studied using viscometric and IR-spectroscopic research methods. Viscometric analysis determined the viscosity and flow characteristics of the oil, providing information about its quality indicators during operation. The IR-spectroscopic method allowed for the identification of components and chemical interactions within the lubricating oil. The changes in the physical-mechanical properties of a special coating applied with the lubricating oil were studied using a specialized SHIMADZU AGS-X device. This research demonstrated the possibilities of determining the physical-mechanical properties of the new lubricating oil and ensuring its compliance with quality standards.

АННОТАЦИЯ

Новое смазочное масло, синтезированное на основе масла Махсар, гриильного масла, тиомочевины, поликротонового альдегида и стеарата кальция, было изучено с использованием вискозиметрических и ИК-спектроскопических методов исследования. Вискозиметрический анализ позволил определить вязкость и текучесть масла, что дает информацию о его качественных показателях в процессе эксплуатации. Метод ИК-спектроскопии позволил идентифицировать компоненты и химические взаимодействия внутри смазочного масла. Изменения физико-механических свойств специального покрытия, нанесенного со смазочным маслом, изучались с помощью специализированного прибора SHIMADZU AGS-X. Данное исследование продемонстрировало возможности определения физико-механических свойств нового смазочного масла и обеспечения его соответствия стандартам качества.

Keywords: IR spectroscopy, Mahsar oil, viscometer, temperature, grill oil, strength, thiourea, polycrotonaldehyde, relative elongation, calcium stearate.

Ключевые слова: ИК-спектроскопия, масло Махсар, вискозиметр, температура, гриильное масло, прочность, тиомочевина, поликротоновый альдегид, относительное удлинение, стеарат кальция.

INTRODUCTION

Due to the rapid growth of the population, industrialization, and the increasing number of vehicles, the demand for energy resources is sharply rising. At the same time, the production and use of traditional petroleum-based lubricating oils have a negative impact on the environment. The limited reserves of oil, the accumulation of waste, and the release of harmful substances into the atmosphere necessitate the search for sustainable and environmentally safe alternative sources. From this perspective, the creation of biodegradable lubricating oils based on renewable raw materials has become an urgent task [1].

Mahsar (safflower), as an oilseed crop, holds high agronomic value, and the oil obtained from its seeds is considered a promising raw material for the production of lubricating materials in terms of its chemical composition and physical properties. The unsaturated fatty acids in Mahsar oil ensure its good fluidity properties, low pour point, and high lubricating ability. This allows it to be used in various friction pairs [2].

Lubricating oils synthesized on the basis of Mahsar offer a number of advantages compared to traditional mineral oils. They are biodegradable, causing less harm to the environment when released into soil and water bodies. Furthermore, their high lubricating ability and natural polar structure help reduce the coefficient of friction and decrease wear. In addition, their oxidative stability and heat resistance can be significantly increased through chemical modification (esterification, epoxidation, addition of antioxidant additives) [3].

However, Mahsar oil also has disadvantages such as a natural tendency to oxidize and relatively low stability at high temperatures. Nevertheless, these problems are being effectively solved through the use of modern additives and stabilizers. As a result, Mahsar-based lubricating oils can be used as an environmentally friendly and effective alternative in mechanical engineering, agricultural machinery, and industrial equipment.

Lubricating materials synthesized on the basis of Mahsar oil, due to their derivation from renewable sources, biodegradability, and high lubricating properties, align with the principles of sustainable development and could potentially serve as an effective substitute for petroleum-based lubricating oils in the future [4].

Purpose of the Research: the purpose of the research is to develop an effective method for synthesizing lubricating oils based on local raw materials, particularly Mahsar oil, which possess high lubricating ability, reduce friction and wear, are resistant to oxidation, and are biodegradable after their service life. To achieve this goal, the study aims to analyze the chemical composition and physical-mechanical properties of Mahsar oil; to increase its thermo-oxidative stability, reduce the coefficient of friction and wear rate through chemical modification (via esterification, epoxidation, and the introduction of functional additives); and also to assess the environmental safety and biodegradability of the obtained lubricating oils. The ultimate goal is to create innovative lubricating oils based on renewable sources that can serve as an alternative to traditional petroleum-based lubricating materials, cause minimal harm to the environment, and be effectively used in industrial and agricultural machinery.

MATERIALS AND METHODS

The objects of the research were selected as Mahsar oil, grill oil, thiourea, calcium stearate, and polycrotonaldehyde. A multi-stage thermal-reaction synthesis process was carried out in this study. Initially, 300 ml of Mahsar oil was placed in a reaction vessel and thermally treated at a temperature range of 80–85°C for 20 minutes under constant stirring conditions. In this stage, the homogeneity of the system was ensured, and the reactivity of the main substance was activated. In the next stage, 100 ml of grill oil was added to the reaction medium, and the temperature was increased to 90°C. The stirring process was continued for another 30 minutes to enhance the interaction between the components and form a stable reaction medium in the system. Subsequently, 50 g of thiourea was introduced into the reaction mixture. The temperature was raised to 100°C, and the process was continued for 20 minutes. This stage created conditions for the formation of chemical bonds involving the functional groups of thiourea. In the next step, the temperature was increased to 120°C, and calcium stearate was added stepwise to the reaction medium until a thick, homogeneous mass was formed. Stirring was carried out under control for approximately 40 minutes. This stage is crucial for the formation of the product's structure. In the final stage of the synthesis, 50 ml of polycrotonaldehyde was added to the reaction system. The temperature was maintained at 150°C, and intensive stirring was carried out for 10 minutes. This stage ensured the completion of polycondensation and additional structuring reactions. After the reaction was completed, the synthesized product was cooled under natural conditions and placed in a special container. The result was a thick, stable synthetic product that had undergone thermal and chemical treatment stages.

The study of physical-mechanical properties was carried out on a Shimadzu AGS-X 10kN series device. IR spectra of the samples were obtained on a Shimadzu IR Tracer-100 series spectrometer in the wavelength range of 400-4000 cm^-1.

RESULTS AND DISCUSSION

IR spectroscopy is widely used as one of the modern analytical methods for determining the molecular structure of chemical compounds and composite materials. Therefore, the structure of lubricating oils prepared on the basis of Mahsar oil and synthesized with the participation of additives such as grill oil, thiourea, polycrotonaldehyde, and calcium stearate was studied using the IR-spectroscopic method, and the obtained results are presented in Figure 1.

Figure 1. IR spectrum of the lubricating oil synthesized on the basis of Mahsar oil with the participation of additives: grill oil, thiourea, calcium stearate, and polycrotonaldehyde

Results Obtained and Their Analysis: figure 1 shows the IR spectra of lubricating oils obtained based on Mahsar oil, grill oil, thiourea, polycrotonaldehyde, and calcium stearate additives in the range of 3700–400 cm^-1, which reflect the interaction between the triglyceride-based base oil and the functional additives. Specifically, the presence and intensity of carbonyl (C=O) groups characteristic of triglycerides, -CH groups of hydrocarbon chains, N–H and C=S functional groups characteristic of thiourea, and carboxylate (–COO^-) bonds characteristic of calcium stearate were analyzed, spectroscopically confirming that the synthesis process was successful and a new lubricating composition was formed.

Comparative analysis of the IR spectra showed that in the lubricating compositions based on Mahsar oil and grill oil, the stretching vibrations of -CH₃ and -CH₂ groups located in the 3000–2800 cm^-1 region indicate that the hydrocarbon chains are preserved and the structure of the base oil remains intact. The intense band around 1743–1744 cm^-1 is characteristic of the carbonyl (C=O) group in triglyceride molecules, and the presence of this functional group was recorded even after the modification process. This indicates that a compositional change occurred while the chemical skeleton of the base oil was preserved.

In samples synthesized with thiourea, broad bands characteristic of N–H groups in the 3300–3200 cm^-1 range and vibrations characteristic of C–N and C–S bonds in the 1200–1000 cm^-1 interval were identified, confirming that nitrogen- and sulfur-containing functional groups were incorporated into the lubricating system. Such groups can interact adsorptively with metal surfaces, potentially improving anti-wear and anti-friction properties.

In compositions containing calcium stearate, asymmetric and symmetric vibrations of the carboxylate anion (–COO^-) were observed in the 1540–1570 cm^-1 and 1400–1450 cm^-1 regions, spectroscopically proving the formation of a metallic soap structure. Furthermore, the band around 720–730 cm^-1, representing the deformation vibrations of long-chain hydrocarbon radicals, provides information about the degree of structural ordering of the lubricating oils.

Overall, the results of the IR spectroscopic analysis showed that during the synthesis process, functional additives were successfully integrated into the lubricating oils based on Mahsar oil, that there is an interaction between them at the molecular level, and that the obtained compositions possess a stable chemical structure. This scientifically substantiates that the developed lubricating oils may have high operational properties.

The study of changes occurring in the physical-mechanical properties of a special coating as a result of applying the newly synthesized lubricating oil within its composition holds particular scientific significance. Such investigations allow for the assessment of the coating's strength, adhesion, elasticity, wear resistance, and long-term operational stability, serving to scientifically confirm the practical effectiveness of the developed lubricating oil.

These studies were carried out on a SHIMADZU AGS-X tensile testing machine. Rectangular plates, each 7 cm in length and 1 cm in width, were cut from the special coatings as test samples and subjected to uniaxial tensile testing using a standard method. Based on the results obtained, the stress-strain and force-elongation parameters of the samples were determined, and their physical-mechanical properties were evaluated (Figure 2).

Figure 2. Physical-mechanical properties after 1 month of use of: the special coating itself (1, 2); the special coating applied with the lubricating oil synthesized based on Mahsar oil (3, 4); and the special coating applied with a conventional (old sample) lubricating oil (5, 6)

Analysis of Results Obtained from Figure 2

According to the results of the first graph (Force - Elongation), in the state where no lubricating oil was applied to the special coating, the two highest values were approximately 750 N (at ≈3.6 mm elongation) and 600 N (at ≈4.4 mm elongation). These indicators demonstrated the coating's initially high strength and good load-bearing capacity. After the application of the new lubricating oil and storage in field conditions for 1 month, the two average values recorded were approximately 670 N (at ≈2.1 mm) and 640 N (at ≈2.4 mm). In this case, it was observed that while the strength decreased to a certain extent, the structural stability was largely maintained. In the state where the conventional (old sample) lubricating oil was applied and stored in the field for 1 month, the last two values were approximately 480 N (at ≈3.7 mm) and 240 N (at ≈2.0 mm), indicating a significant decrease in load-bearing capacity and a weakening of the material's structure.

A similar pattern is observed in the analysis of the second graph (Stress - Strain). In the state where nothing was applied to the coating, the two highest values were approximately 75 N/mm² (at ≈12% deformation) and 60 N/mm² (at ≈15% deformation), confirming the initially high mechanical strength of the material. After the application of the new lubricating oil and storage in field conditions for 1 month, the two average values recorded were approximately 66 N/mm² (at ≈8% deformation) and 65 N/mm² (at ≈7% deformation). This indicates that although the mechanical properties decreased to some extent, the coating structure remained relatively stable. In the case where the conventional (old sample) lubricating oil was applied and stored in the field for 1 month, the last two values were approximately 48 N/mm² (at ≈13% deformation) and 24 N/mm² (at ≈6% deformation), showing a significant deterioration in the material's strength and elasticity characteristics.

Overall, analyzing the six main values from both graphs, it was concluded that the sample using the new lubricating oil relatively better preserved its physical-mechanical properties, while the sample with the conventional lubricating oil demonstrated that the new oil imparts better strength and stability to the coating compared to its old counterpart.

Viscometric Analysis

Viscometric analysis plays an important role in the comparative assessment of the rheological properties of new and old lubricating oils. The significant difference in the viscosity indicators of the new lubricating oil, obtained based on Mahsar oil, grill oil, thiourea, and calcium stearate, compared to the old sample is explained by changes in the quantity of its constituent components and structural characteristics. The obtained results allowed for a scientifically based assessment of the oil's coating stability on surfaces, its spreadability, as well as its flow and adhesive properties during operation.

Viscometric studies were conducted to determine the molecular weight of the new lubricating oil synthesized based on Mahsar oil, grill oil, thiourea, polycrotonaldehyde, and calcium stearate. For the study, toluene with a density of ρ = 0.88 g/cm³ was chosen as the solvent, and 5%, 7%, 10%, 15%, and 20% solutions of the oil were prepared. All measurements were carried out using a capillary viscometer with a diameter of 0.99 mm at a temperature of 30°C. The flow time of pure toluene through the viscometer under these conditions was 2.8 seconds. It was observed that the flow times for the solutions increased proportionally with increasing concentration: they were recorded in the ranges of 2.91–2.99 s for the 5% solution, 3.40–3.67 s for the 7% solution, 4.32–4.55 s for the 10% solution, 19.43–21.38 s for the 15% solution, and 32.14–39.02 s for the 20% solution. Based on the obtained results, the relative and specific viscosity values were calculated, and their dependence on concentration was analyzed. Subsequently, using the Staudinger equation, the conditional (approximate) molecular weight of the new lubricating oil was determined, and its value was found to be M ≈ 1.1 × 10⁴, which confirms that the substance under study is a high-molecular-weight compound.

Viscometric analyses were conducted to evaluate the molecular characteristics of the conventional oil (solidol) and to compare them with the newly obtained lubricating oil. In these studies, Toluene with a density of ρ = 0.88 g/cm³ was used as the solvent, and 5%, 7%, 10%, 15%, and 20% solutions of the old solidol were prepared.

 All measurements for the old sample (solidol) were carried out using a capillary viscometer with a diameter of 0.99 mm at a temperature of 30°C; the flow time of pure toluene under these conditions was 2.8 seconds. It was observed that the flow time of the solutions increased gradually with increasing concentration: they were recorded in the ranges of 2.40–2.54 s for the 5% solution, 2.94–3.07 s for the 7% solution, 3.95–4.28 s for the 10% solution, 5.13–5.22 s for the 15% solution, and 5.68–6.02 s for the 20% solution. The results indicate that, in the old sample, although the viscosity increased with concentration, at higher concentrations (especially 15–20%), the flow time increased moderately rather than sharply. This reveals a significant difference when compared to the new lubricating oil, where at 15% and 20% concentrations, the viscosity increased very sharply, and the flow time multiplied several times. The conducted viscometric studies showed that the viscosity indicators of the new lubricating oil are higher and more sensitive to concentration compared to the old sample. This confirms that intermolecular interactions are stronger in the new composition and that its operational properties have been better formed.

CONCLUSION

In conclusion, the viscometric and IR-spectroscopic analyses of the new lubricating oil synthesized based on Mahsar oil, grill oil, thiourea, polycrotonaldehyde, and calcium stearate confirmed that it possesses stable rheological properties and that targeted chemical interactions occurred between the constituent components. The results of physical-mechanical tests, obtained using a SHIMADZU AGS-X universal testing machine when the oil was applied within a special coating, showed a positive dynamic in the coating's strength, adhesion, and deformation resistance indicators. The obtained results demonstrate that the new lubricating oil is scientifically substantiated in terms of its composition and functionality, that it has the potential for effective application under operational conditions, and that it may comply with existing quality standards. Furthermore, this work lays the foundation for drawing important scientific conclusions, both theoretical and practical, in the direction of modifying lubricating oils and creating new generation materials for functional coatings.

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