Mineral Base Oil Research Articles

Suitability of Test Procedures for Determining the Compatibility of Seal Materials with Ionic Hydraulic Fluids.

The compatibility of seal materials with the working fluid is crucial for the flawless, energy-saving, environmentally sustainable, and safe operation of any technical system. This is especially true for hydraulic systems operating under high operating pressure. The problem of materials compatibility comes into play when either a new type of seal material or a new type of fluid comes into use. The paper discusses the research findings regarding material compatibility testing of new high-tech ionic hydraulic fluids with commonly used seal materials. Due to the completely different chemical composition of these new fluids compared to the classical mineral-based oil, for these fluids, there are no standardized testing procedures. In these cases, we can only lean on the Standards that apply to classical fluids, which can lead to incorrect results. In the forefront of the paper is the discrepancy between the results obtained by the standardized test, and the test under real operating conditions. FKM, an excellent material for seals, proved to be the most suitable in the case of using ionic hydraulic fluid, according to a standardized test. However, it failed in the comparison test under real operating conditions, as the cylinder leaked. NBR seals proved to be a better solution.

Biophysical impact of lubricating base oil aerosols on natural pulmonary surfactant film

Lubricating base oils have been extensively employed for producing various industrial and consumer products. Therefore, their environmental and health impacts should be carefully evaluated. Although there have been many reports on pulmonary cytotoxicity and inflammatory responses of inhaled lubricating base oils, their potential influences on pulmonary surfactant (PS) films that play an essential role in maintaining respiratory mechanics and pulmonary immunity remains largely unknown. Here a systematic study on the interactions between an animal-derived natural PS and aerosols of water and representative mineral and vegetable base oils is performed using a novel biophysical assessing technique called constrained drop surfactometry capable of providing in vitro simulations of normal tidal breathing and physiologically relevant temperature and humidity in the lung. It was found that the mineral oil aerosols can impose strong inhibitions to the biophysical property of PS film, while the airborne vegetable oils and water show negligible adverse effects within the studied concentration range. The inhibitory effect is originated from the strong hydrophobicity of mineral oil, which makes it able to disrupt the interfacial molecular ordering of both phospholipid and protein compositions and consequently suppress the formation of condensed phase and multilayer scaffolds in a PS film. Environmental ImplicationUnderstanding the biophysical influence of airborne lubricating base oils on pulmonary surfactant (PS) films can provide new insights into the environmental impacts and health concerns of various industrial lubricant products. Here a comparative study on interactions between an animal-derived natural PS film and the aerosols of water and representative mineral and vegetable base oils under the true physiological conditions was conducted in situ using constrained drop surfactometry. We show that the most frequently used mineral base oil can cause strong inhibitions to the PS film by disrupting the molecular ordering of saturated phospholipids and surfactant-associated proteins at the interface.

Unravelling the Effect of Chain and Branch Content on Viscosity of Polyisobutylene-Mineral Oil Blends by Modelling and its Tribological Properties

The viscosity index is a fundamental property of lubricating oils and greases that significantly affects their lubrication performance under diverse temperature conditions. This study aims to investigate the influence of chain length and branch content on the viscosity of polyisobutylene (PIB)-blend mineral oil. To achieve this objective, mathematical models are employed to predict the specific volume, Vander Waals volume, structural factor, friction factor, molecular weight, and specific viscosity of lubricant blends and their correlation with macromolecular structure. Furthermore, analytical techniques such as Gel Permeation Chromatography (GPC), Nuclear Magnetic Resonance (NMR), and CHNS elemental analyzer are utilized to forecast the appropriate molecular structure of mineral-based oil. The purpose of this research is to comprehend the impact of the macromolecular structure of lubricants on their viscosity, particularly in the case of polyisobutylene (PIB)-blend mineral oil. Overall, the concentration of PIB was found to directly influence the friction (15.3%) and wear (5.6%) performance of the mineral oil explored following ASTM 4172 standard. The mathematical models and analytical techniques employed used in this study can accurately forecast the specific volume, Vander Waals volume, structural factor, friction factor, molecular weight, and specific viscosity of lubricant blends and their relationship with macromolecular structure.

The effect of electrical current on lubricant film thickness in boundary and mixed lubrication contacts measured with ultrasound

This work explores experimentally the effects of DC electrical currents on lubricant film thickness alteration in lubricated sliding steel contacts in the boundary and mixed regime as measured by ultrasound. The experiments were performed in a two-electrode cell-based pin-on-disk tester instrumented with ultrasonic transducers. Unelectrified and electrified tribological tests were conducted on steel flat-on-flat contacts under various speeds and loads using both a mineral base oil and a gear oil. Film thickness, coefficient of friction (CoF), and electrical contact resistance (ECR) were measured during short experiments (30 s) in unelectrified and electrified (1.5 and 3 A) conditions. The results suggest that film thickness, CoF, and all ECR are altered by passing DC currents through the contact. In particular, film thickness increased and decreased, respectively, by applying electricity at the different speeds and loads tested. These alterations were majorly ascribed to oil viscosity decrease by local heat and surface oxidation caused by electrical discharge and break down at the interface.

Selective lipase-catalyzed hydrolysis for removal of diglyceride in palm oil

Palm-based transformer oil is an environmentally friendly and renewable alternative to mineral-based oil for use as an insulating oil. However, the crystallization of palm oil at low temperatures can cause operational issues in transformers. In this research, low diglyceride palm oil is first proposed as a promising base stock for palm-based insulating oil to overcome this issue. The research focuses on the removal of diglycerides (DG) from palm oil by selective enzymatic hydrolysis under a solvent-free system. The results indicate that the lipase GS-250G specifically catalyzes only DG molecules without hydrolyzing TG molecules, despite TG molecules being more prone to hydrolysis than DG molecules due to their higher concentration in palm oil. This unique behavior is probably attributed to steric hindrance by bulky amino acids surrounding the catalytic pocket of lipase GS-250G. Under optimum conditions (30 °C, atmospheric pressure, water content of 16 wt%, agitation speed of 850 rpm, lipase loading of 0.005 wt%, and 4 h of reaction time), the lipase GS-250G reduced the DG content in palm oil from 7 % to 0.5 % with a degree of DG hydrolysis of 95 %. After purification, the final product was composed of 99 % triglyceride (TG). The cold stability test suggested that the nucleation and crystallization rate during the crystal formation of palm oil were reduced by decreasing the DG content. The finding suggests that the proposed procedure in this work is a rapid and environmentally sustainable method for DG removal, which can solve the major problem of palm oil. This discovery opens new opportunities for palm oil to be used as a raw material only for insulating oil but also for various palm based products.

Structure–Performance Relationship of Coal-Based Lubricating Base Oils and Sensitivities to Typical Additives

The relationship between the structure characteristics and performances of coal-based hydrogenation isomeric (CTL) base oil and metallocene-catalyzed coal-based poly-alpha-olefin (mPAO) base oil is clarified in this paper. CTL and mPAO were compared with typical petroleum-based and natural gas-based commercial API III and IV base oils. Pressurized differential scanning calorimetry (PDSC), the rotary bomb oxidation test (RBOT), and a four-ball friction tester were used to evaluate the oxidation stability and lubrication performance of base oils under different working conditions. The sensitivity of different base oils to typical antioxidants and extreme-pressure antiwear agents was compared. In particular, the composition and structure of CTL base oil are clearly different from GTL and mineral base oil. The coal-based CTL and mPAO base oils exhibit commendable viscosity–temperature properties, coupled with low-temperature fluidity, fire safety, and minimal evaporation loss. The lubricating properties, oxidation stability, and sensitivity to extreme-pressure antiwear agents of CTL are close to those of similar base oils. However, the sensitivity of CTL to typical antioxidants is relatively poor. In addition, compared with commercial PAO base oil, mPAO has a lower isomerization degree and fewer isomerization types. The oxidation stability and sensitivity to typical antioxidants of mPAO base oil are comparable with those of commercial PAO base oil, while its lubrication performance and sensitivity to typical extreme-pressure antiwear agents are significantly better than those of commercial PAO base oil.

Исследование трибологических свойств смазок с эксплуатационными добавками

The paper presents results investigated a lubricating properties of SN 150 mineral base oil modified with exploitation preparations R-2000 (soft material based preparation), MOTOR LIFE (chemical preparation) and Acorox 880 (zinc preparation). The test was conducted using the T-02 tester (four ball apparatus).

Frequent oil baths and skin barrier during infancy in the PreventADALL study.

In the general population randomized controlled trial PreventADALL, frequent emollient bath additives from 2 weeks of age did not prevent atopic dermatitis, while the effect on skin barrier function throughout infancy is not established. The primary aim of this exploratory substudy was to assess the effect of mineral-based oil baths on transepidermal water loss (TEWL) and dry skin through infancy, and secondarily to explore if filaggrin (FLG) mutations modified the effect. Overall, 2153 infants were included and randomized to either the 'Skin intervention' (SI) group (n = 995) (oil bath 4 times weekly from 2 weeks through 8 months) or 'No skin intervention' (NSI) group (n = 1158), with TEWL measurements at 3, 6 and/or 12 months of age. Information on FLG mutation status was available for 1683 of these infants. Effects of the skin intervention on TEWL and dry skin through infancy were assessed by mixed-effects regression modelling. Background characteristics and protocol adherence were collected from electronic questionnaires, birth records and weekly diaries. The TEWL (95% confidence interval) was on average 0.42 g m-2 h-1 (0.13-0.70, P = 0.004) higher in the SI group compared with the NSI group through the first year of life, with significantly higher levels at 3 months [8.6 (8.3-9.0) vs. 7.6 (7.3-7.9)], but similar at 6 and 12 months. Dry skin was observed significantly more often in the NSI group compared with the SI group at 3 months (59% vs. 51%) and at 6 months of age (63% vs. 53%), while at 12 months of age, the difference was no longer significant. At 3 months, the TEWL of FLG mutation carriers was similar to the TEWL in the SI group. No interaction between SI and FLG mutation was found in the first year of life. Infants given frequent oil baths from 2 weeks of age had reduced skin barrier function through infancy compared with controls, largely attributed to higher TEWL at 3 months of age, while the skin at 3 and 6 months appeared less dry in infants subjected to the skin intervention.

Tribological behavior of DLC film models in base oils: Analysis of influence of sp3/sp2 ratio and hydrogen content

DLC coatings have been proven in formulated oils used in the automotive industry. The development of electric cars and its consequences on the future of the internal combustion engine makes it increasingly necessary that these coatings take their place in other applications where lubrication is generally of lower quality such as for example strips cold rolling where DLC shows significant potential both for production and finishing cold rolling. As a result, the interest of the behavior of these coatings in base oils takes on a new dimension. In this study, we explore the influence of the composition and the sp3/sp2 ratio on tribological behavior of DLC coatings in mineral and synthetic base oils. Hydrogenated DLC films deposited by conventional PECVD with various levels of hydrogen measured by Elastic Recoil Detection Analysis (ERDA) and non-hydrogenated DLC films deposited by PLD in the nanosecond mode (ns-PLD) and by cathodic arc evaporation, thus allowing to have different sp3/sp2 ratios confirmed by Multiwavelength Raman spectrometry, are tested and compared. The tests are performed on a ball-on-flat device with coated balls to better evaluate wear level. The behavior of highly hydrogenated DLC is of particular interest; with a very high level of durability in both base oils and friction level which comparatively varies between low and very low depending on the base oil.

Comparison between methacrylate copolymers and their magnetite nanocomposite as pour point depressant for lubricating base oil

A novel pour point depressant was synthesized by developing a polymeric nanocomposite using polymethacrylate and magnetite nanoparticles. The primary objective was to assess and compare the efficacy of PMA and PMA/Fe3O4 nanocomposite in reducing the gelation point, yield stress, apparent viscosity, and pour point of waxy crude oil. Extensive assessments were conducted to evaluate the performance of these additives. Rheometry tests were employed to measure the pour point of the lubricating oil pour point following the addition of PMA and PMA/Fe3O4 nanocomposite. The findings demonstrated a significant reduction in pour point, reaching values of − 18 °C, − 27 °C, − 24 °C, and − 36 °C for CP1, CP2, NP1, and NP2, respectively, at an optimal concentration of 10,000 ppm. Various characterization techniques such as Fourier Transform Infrared Spectrometer, Proton Nuclear Magnetic Resonance, X-ray Diffraction, Scanning Electron Microscope, Differential Scanning Calorimetry, Dynamic Light Scattering, Polarized Optical Microscope, and Gel Permeation Chromatography were utilized to analyze the polymers. Furthermore, the effectiveness of each polymer as a viscosity index improver (VII) and pour point depressant for mineral-based oil was evaluated. The mechanism of action of the polymers as pour point depressants was investigated through photomicrographic analysis. Additionally, the rheological properties of the formulated lubricant were assessed and reported. Thermogravimetric analysis was used to determine the thermal stability of the polymers, revealing that the copolymer nanocomposites exhibited higher thermal stability, viscosity index (VI), and molecular weights compared to the copolymers alone. These enhancements in thermal stability and molecular properties contributed to the improved pour point depressant (PPD) properties. Overall, the study successfully synthesized a novel pour point depressant and evaluated its performance using various tests and characterization techniques. The results demonstrated the effectiveness of the additives in reducing the pour point and improving the thermal stability of the lubricating oil.

The influence of various grease compositions and silver nanoparticle additives on electrically induced rolling-element bearing damage

Leakage currents accelerate surface degradation of metal contacts via small scale arcing across lubricating films, but recent observations suggest that metallic nanoparticle additives in lubricants may be useful to improve contact performance. These findings prompted a study that examined electrically induced surface pitting of steel contacts in the presence of several lubricating greases including some containing nanometer-sized colloidal silver (Ag) particles. Reciprocating rolling sphere-on-disk experiments were conducted under electro-tribological loads employing polyurea greases derived from mineral and synthetic base oils with and without additives. Friction forces and electrical resistance were monitored continuously during the tests; surface changes were characterized by means of optical spectroscopy, stylus profilometry, and scanning electron microscopy (SEM) including compositional analysis using energy dispersive spectroscopy (EDS). The observations demonstrate that surface pitting induced by arcing occurs mainly at the points were the rolling motion changes direction and that eroded metal is deposited along the wear grove. Micron-sized pits are formed which contain carbon and oxygen indicating that arcing causes decomposition of the hydrocarbon lubricants. Numerous findings indicate a significant inhibition of pitting is induced by the Ag nanoparticles; some greases containing other additives exhibit a similar, although less pronounced, effect.

Performance evaluation of hybrid biodegradable oils as a lubricant during cylindrical turning of AISI 304 austenitic stainless steel

<abstract> <p>In the engineering sector, machining plays a significant role. The ability of the cutting zone to dissipate heat has grown in importance for the machining industry’s sustainability. Government legislation is pushing the industry to use fewer conventional lubricants as concerns about the effects on the environment and human health grow. This shifts attention to Minimum Quantity Lubrication (MQL) and biodegradable oils. The purpose of this study is to show how well two vegetable oils, in their raw forms, perform as cutting fluids during the MQL turning process of AISI 304 stainless steel. Each vegetable oil’s physiochemical and lubricating qualities were examined separately. After that, the two oils that comprised the hybrid vegetable oil were blended at a ratio of 0.5:0.5. During machining with an external threading tool, the hybrid vegetable oil was compared to its equivalent mineral-based oil in terms of cutting temperature and surface roughness. The Taguchi L9 orthogonal array was used in the study. According to the data, the cutting temperature was lowest when cutting with mineral oil, and highest when cutting with a hybrid mixture. In general, the mineral oil produced a reduced surface roughness compared to the vegetable oil mixture by about 68.6%. The combo of palm kernel and yellow orleander oil marginally outperformed mineral by about 2.3% when it came to cutting temperature. The significance of this study is to develop a more sustainable and environmentally friendly lubricants for industrial applications.</p> </abstract>

Development of high free fatty acid crude palm oil as a biodegradable electrical liquid insulator as an alternative to mineral oil-based insulators

Mineral-based oil is now often used for transformer oil. Unfortunately, this kind of oil is harmful and unfriendly to the environment, necessitating the use of vegetable-based products that are both ecologically benign and biodegradable. With its properties, crude palm oil (CPO) might be a possibility for a vegetable-based insulator. Concerning it, the goal of this study was to create a method for converting CPO into an insulator that fulfilled IEC 62770 requirements. The researchers created a CPO-based insulator using degumming, filtration, distillation, and a vacuum drying technique in their work. At vacuum pressures ranging from 15% to 65% vacuum and temperatures ranging from 150 °C to 200 °C, 0.05% phosphoric acid, 5% bleaching earth, and 10% zeolite were used in the degumming process. The best measurement results showed that the values of breakdown voltage and kinematic viscosity of 60 kV and 12.7 cSt, respectively, met the requirements. The moisture content was higher than the required value, while the acid content was still relatively high, namely 1.4 mg KOH/g, thus requiring further treatment. After treatment using 2% KOH, the acidity became 0.01 mg KOH/g, and the moisture content was 176 ppm thus meeting the requirement. The color of the insulator produced was light yellow, bright, and clear. The best treatment parameter combination found was a pressure of 51.9% vacuum with a temperature of 168.7 °C. This research showed that the vacuum pressure had a significant effect on moisture, kinematic viscosity, and acidity, while temperature had a significant effect on breakdown voltage and acidity.

Utilization of catfish fat by-products for the biological base oils synthesis

In this work, catfish fat by-product was utilized as feedstock in the synthesis of biological base oils. The study performs the effect of parameters on the reaction yield. 91.2% in (H2O2/CH3COOH/C=C) molar ratio of 4.5/1.5/1.0, the temperature of 50 oC, and 3 hours reaction time. The yield of the ring-opening reaction of epoxy with acetic anhydride reached at 90.2% in (acetic anhydride/epoxy) molar ratio of 1.5/1.0, the temperature of 95 oC, and 4.5 hours reaction time. The main functional groups of catfish oil starting material, epoxy catfish oil, and polyester catfish oil final product were identified by FT-IR and 1H-NMR spectral analysis methods. The observed results show that the catfish oil epoxidation reaction with a mixture of H2O2 and CH3COOH and the ring-opening reaction of epoxy with (CH3CO)2O, H2SO4 catalyst has occurred strongly and obtained product of catfish polyester oil could use as an alternative to mineral base oils and an environmentally friendly product.

Lube Oil Performance Enhancement Using Nano-Polymers Additives during Copolymerization Reaction

Under the parameters of normal engine operation, lubricating oil typically experience periodic shifts in its viscosity. Because of this, engine oils often include polymeric additives that are referred to as viscosity modifiers. The oil is able to give acceptable fluid lubrication at extreme temps due to these additives, which are oil-soluble polymers. The aim of present work to use polymers in form of nano-composites such as Styrene, Octadecyl-methacrylate (ODMC) and Dodecyle-methcrylate (DDMC) for lube oil viscosity index and pour point enhancement during copolymerization reaction. The benzoyl peroxide was used as an initiator. Solubilizes were made using SN-150 mineral base oil from the Al-Dorha refineries in Baghdad, which had a viscosity index of 128, and a viscosity range of 0 to 100°C. Styrene and methacrylate monomer combinations were copolymerized in an SN-150 mineral base oil solution in a nitrogen atmosphere at 60-80°C. A 200 mm3 oil glass reactor fitted with a magnetic stirrer and a reflux condenser was used to conduct the reactions. Five percent by weight of the total monomer was the concentration used. With respect to the monomers, the initiator concentration was 1.0% wt. Seven hours are needed for the whole reaction cycle. The copolymer composition was modified from 5 to 25% wt.% styrene by changing the monomer combination ratio. The advanced statistical analysis is performed to find the optimum conditions by mean of surface response and multiple regression using MINITAB. The optimization finding is obtained at Styrene of 5%, DDMC of 18% and ODMC of 18%, which promotes viscosity index of 197 leading to 51% enhancement in Al-Dora lube oil.

Dialkyl phosphonate with carboxylic acid as antiwear additives for ester-base lubricants

Ester-base oils are commonly used in environmentally adapted lubricants (EALs) because of their biodegradability. However, their antiwear performance is difficult to improve using the conventional lubricant additives developed for mineral-base oils. In this study, dialkyl phosphonates with various functional groups were designed as antiwear additives for ester-base oils. The antiwear performances of these phosphonates were evaluated using four-ball tests. The results suggest that dialkyl phosphonate with carboxylic acid (DAPA) has better antiwear performance in ester-base oils than that of other phosphonates and conventional phosphorus additives. Remarkably, DAPA exhibits better antiwear performance under severe test conditions in ester-base oils than in poly-alpha olefin. X-ray photoelectron spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy were used to study the chemical compositions of steel surfaces after friction and better understand the antiwear mechanism of DAPA, particularly in ester-base oils.

Experimental investigation of the effects of boron oil additive in internal combustion engine

Using additives to engine oils increases engine performance, extending engine maintenance life, boosting the competitiveness of mineral-based oils technically and economically. In this study, the effects of liquid boron oil additive added to mineral-based 10 W-40 engine lubricating oil used in a single-cylinder diesel engine were investigated. 15 % of the engine oil volume was added to the engine as an additive. Experimental studies were carried out at three different engine speeds (i.e., 1500, 1750, and 2000 rpm). The engine, on which no changes were made, was first run with mineral lubricating oil, and then the experiments were repeated with mineral lubricating oil with 15 % boron additive. In the studies, engine torques, specific fuel consumption, and exhaust emissions (HC, CO, CO2, and NOx) were evaluated. In addition, the effects of operating the engine for 100 h without adding any additives and with oil additives containing 15 % boron were also investigated. It was found that engine torque and EGT increased while BSFC, CO2, HC, and NOx decreased in boron-added mineral lubricating oil for all revolutions. In addition, there was a general decrease in CO emissions. In-cylinder SEM images and oil analyses, which were operated with a 15 % boron additive to the engine oil, showed that the boron additive positively affected the engine.

FRICTIONAL PROPERTIES OF GREASE LUBRICATED CONTACT AT DIFFERENT OPERATING REGIMES OF LUBRICATION

The implementation of electric vehicles introduces new tribological challenges, specifically for bearing systems. Up to 90% of the electric motor rolling bearing is reported to be lubricated by grease. However, the improper selection of grease types can result in premature rupture of the lubricant film due to excessive heat generation during operation. This paper focuses on analysing the frictional behaviour of various commercially available greases intended for use in bearing systems of passenger cars, considering the same mineral base oil with different types of thickener. To study the frictional and wear behaviour, a ball-on-disc friction tester is used to test the selected greases. Experimentally, the studies greases showed similar Stribeck curve trend showing that thickener used in grease plays crucial role in influencing the friction and wear properties. Thus, present study helps to provide knowledge for optimisation of grease for electric motors.

Degradation Effects of Base Oils after Thermal and Electrical Aging for EV Thermal Fluid Applications

This study presents the experimental results of the effects on base oils after thermal and electrical aging to determine key parameters of next-generation fluids for thermal management in electric vehicles. The test fluids selected were a mineral base oil API G-III, an API G-IV Polyalphaolefin (PAO), a diester, and a polyolester, all of which had similar kinematic viscosity (KV100 = 4 cSt). All were initially characterized with measurements of density, viscosity, thermal conductivity, specific heat capacity, breakdown voltage, resistivity, and dissipation factor. They underwent two separate aging processes, one thermal, heating the test fluid at 150 °C for 120 h with a copper strip as a catalyst; and the second one an electrical aging process, with the application of 1000 breakdown voltage discharges. The same properties were measured again after each aging process and compared to the initial ones. It was found that the thermal properties ranged with similar values and did not suffer major changes after the aging processes, unlike electrical properties, which vary between samples and after thermal and electrical stress. The insights gained from this study have implications for both the development of next-generation e-thermal fluids and the future standardization of these fluids for EV thermal management applications. The findings of this study underscore the significance of formulating and selecting a suitable dielectric fluid for EV thermal management. By leveraging the insights provided, researchers and engineers can advance in the development of efficient and reliable e-thermal fluids while working towards future standardization to enhance the performance and safety of EV battery systems.

A practical approach for kinetic analysis of hydrogenation of complex mineral base oil

A practical approach for kinetic analysis of hydrogenation of complex mineral base oil