Environmental Friendly Lubricants Research Articles

Characterization and formulation of an environment-friendly lubricant from Pongamia (Millettia Pinnata) oil using biodegradable additives

Global efforts are being undertaken to increase the automobile industry's energy efficiency, reliability, and environmental friendliness. There are techniques to lessen the environmental issues caused by machines, such as using lightweight materials, exhaust gas after-treatment, less toxic fuel, and controlled combustion. To decrease friction and wear, especially in engines and drive trains, proper lubrication is necessary at the required operating conditions for an automobile's safe and dependable operation. Mineral, synthetic, and semi-synthetic oils have been employed as lubricants; however, their disposal damages the ecosystems. Concerns about environmental deterioration are also raised by the emissions of metal traces such as calcium, magnesium, iron particles, and zinc due to burning these lubricants. Due to the limited supply of petroleum crude oil, these lubricants' present and future prospects are dismal. There is a worldwide quest for an alternative lubricant due to the environment being harmed by use of petroleum-based lubricants.The different characterization of the lubricant properties for the neat Pongamia base oil (PO) includes assessments of chemical, oxidative, rheological, thermal, and tribological properties. The fatty acid profile of PO has to be estimated using Gas chromatography–mass spectrometry. The Oxidative stability of PO should be estimated using the Differential scanning calorimetry (DSC) test. The rheological characterization should be done by evaluating kinematic viscosity, viscosity index, and dynamic viscosity. Tribological properties are studied using a four-ball tester tribometer. The lacking properties of neat PO is identified and improved using suitable additives such as antioxidants, viscosity improver, pour point depressants, anti-wear additives, etc. The biodegradability test of the formulated oil is done using bacterial turbidity assay and toxicity is checked of the final formulated oil. An IC engine test is done to check the performance of the engine and wear using formulated lubricant from PO.

Toward high-performance lubricants: Rational design and construction of supramolecular oil gels by amphiphilic telechelic polymers to stabilize two-dimensional nanomaterials in base oils

Two-dimensional (2D) nanomaterials have long been promised as environment-friendly lubricant additives. However, their agglomeration in base oils have largely limited their practical applications. Here, we report the supramolecular oil gels constructed by amphiphilic telechelic polymers poly(2-hydroxyethyl methacrylate)-block-poly(stearyl methacrylate)-block-poly(2-hydroxyethyl methacrylate) in base oils. 2D nanomaterials GO, h-BN, and g-C3N4 can be homogeneously stabilized in the oil gels over one year, which are the most stable oil dispersions of the 2D nanomaterials reported to date. The oil gels demonstrate excellent lubricating performance, which could be attributed to the 60 − 90 nm thick tribofilms formed on the worn areas. These supramolecular oil gels not only represent an efficient and versatile platform for stabilizing 2D nanomaterials, but also a universal strategy to explore high-performance lubricants.

Synthesis and Tribological Properties of Bis(2-hydroxyethyl)ammonium Erucate as a Potential Environmentally Friendly Lubricant and Lubricant Additive

Recently, environmentally friendly lubricants and their additives have been of great interest. Using such lubricants can provide a few benefits, namely: nontoxicity and biodegradability when exposed to groundwater or soil. Moreover, renewable raw materials could be used to produce these lubricants. This study aims to synthesize bis (2-hydroxyethyl)ammonium erucate protic ionic liquid containing a renewable counterpart-erucic acid. The synthesis of bis (2-hydroxyethyl)ammonium erucate, its physical properties, solubility in the base lubricating fluid, and tribological properties were evaluated. The study shows that even though the investigated protic ionic liquid is liquid at room temperature, it has a very high kinematic viscosity, which drops when the temperature increases. Bis (2-hydroxyethyl)ammonium erucate can be dissolved in water up to 3 wt%. It also has excellent lubricity when used as a neat lubricant and could be successfully applied as a lubricity-enhancing additive in water.

Investigation of Dioscorea oppositifolia L. as green lubricant in water-based drilling fluids

With the increasing exploration of unconventional wells, such as horizontal wells and complex wells, and the increasingly strict national environmental protection regulations, drilling fluid lubricants are in increasing demand. High-performance and environment-friendly lubricants for water-based drilling fluids are urgently needed. In this work, Chinese yam (Dioscorea oppositifolia L.) was investigated as a drilling fluid lubricant; the effects of Chinese yam slurry on drilling fluid lubricating properties at different temperatures were investigated and the compatibility and inhibitory properties of Chinese yam slurry were studied. The results show that the viscosity coefficient of the mud cake is reduced by 44.5% as 1.5% Chinese yam slurry was added to water-based drilling fluids. Chinese yam also has certain temperature resistance in drilling fluids, and it can inhibit the swelling of clay. Chinese yam slurry is competitively compatible with other drilling fluid additives, and the lubricity of modified drilling fluids can also be improved effectively. The lubrication mechanism of Chinese yam slurry was investigated through thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and contact angle tests.

Lignin-Based Additives for Improved Thermo-Oxidative Stability of Biolubricants

There is an environmental concern regarding the use of petroleum-based lubricants, which are generally toxic and nonbiodegradable. Biobased lubricants, such as vegetable oils, are the alternative: they show excellent lubricity, are readily biodegradable and nontoxic. However, a major disadvantage of using vegetable oils in lubricant applications is their lack of thermo-oxidative stability, which can be improved by antioxidant additives. Here, we propose the use of lignin-based additives in biolubricant formulations to improve this feature, based on lignin’s known antioxidant properties. To ensure a stable dispersion in vegetable oil, lignin was partially esterified. Antioxidant properties of lignin before and after palmitoylation were demonstrated in a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Four different lignin-based fractions, commercial Protobind P1000 soda lignin from straw, solvolytically fractionated Protobind P1000 lignin and two lignin fractions from reductively catalyzed fractionation (RCF) of native birch wood, were tested in biolubricant formulations with castor oil as base oil. Those lignin fractions exhibited excellent performance compared to butylated hydroxytoluene (BHT), a commonly used petroleum-based antioxidant. Formulations of modified lignin in castor oil possess improved thermo-oxidative stability, as illustrated by their increased oxidation induction time. Additionally, rheological and tribological tests demonstrate similar, or in some cases improved, lubricating properties compared to castor oil. This study showcases the successful incorporation of lignin-based antioxidants in biolubricant formulations, tackling the major disadvantage of vegetable oils as environment-friendly lubricants.

Natural emulsifier assisted lubricity of the colloidal system: Effect of natural emulsifier concentration

Environmental needs, human health issues, government regulations have motivated this work to explore an alternative to mineral oil-based systems to vegetable oil-based environmental friendly lubricants. The present study is an attempt to use natural products (soybean oil and Gum Arabic) to develop environmental friendly oil-in-water emulsion to be used as metalworking fluid. The role and effect of Gum Arabic (GA) concentration on emulsion stability, wettability, and lubricity is explored. Three concentrations of GA corresponding to critical micelle concentration (CMC), below CMC and above CMC are selected to formulate the emulsions (Formulated fluids (FFs)). The emulsion characteristics (droplet size and zeta potential), pH, wetting dynamics, and lubricity are evaluated using dynamic light scattering (DLS), pH glass electrode, Goniometer, and four-ball tester (FBT), respectively. Worn surfaces are analysed using Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscope (FESEM). The physical characteristics and tribological responses suggest that the FF @ CMC of GA exhibited better stability, lubricity, and antiwear properties than other formulations. Different responses of FFs are benchmarked with that of mineral oil-based commercial fluid (CF). FF @ CMC of GA showed a better anti-friction and similar anti-wear response as compared to CF. The excellent lubricity of the FF @ CMC of GA is attributed to the formation of the low shear strength stable lubricious film due to the active participation of GA molecules at the tribo-pair interface.

A Review on Improvement of Hydrodynamic Journal Bearing by using Bio-Lubricant

Journal bearings typically consists of metal sleeve that fits around a shaft. The sleeve is held in place within a housing. The journal is simply place on the shaft that is surrounded and supported by the bearing. Journal bearings can be made out of metallic or non-metallic materials such as bronze, aluminium etc. Bearings are generally made out of material that is softer than the metal of the shaft. Journal bearings typically consists of metal sleeve that fits around a shaft. The sleeve is held in place within a housing. The journal is simply place on the shaft that is surrounded and supported by the bearing. Journal bearings can be made out of metallic or non-metallic materials such as bronze, aluminium etc. Bearings are generally made out of material that is softer than the metal of the shaft. Typically, journal bearings are used in various applications such as turbines, compressors, centrifugal pumps etc. The performance of hydrodynamic journal bearing is depend upon the lubrication. Lubrication provides a thin film between internal sliding surfaces of the bearing components to reduce friction. Nowadays crude oil uses increases day by day. Due to depletion of petroleum resources, increasing its price and environmental pollution interest is developed towards the use of economical, environment-friendly lubricants. Bio-lubricants are made from vegetable oils. They are environment-friendly, non-toxic and also having performance benefits such as high viscosity index, high lubricity, high load carrying capacities, rapid biodegradability etc. In this review paper, to improve performance of hydrodynamic journal bearing and also to replace petroleum oil different types of bio-lubricants were examined.

The lubrication performance and viscosity behavior of castor oil under high temperature

Castor oil is an environment-friendly lubricant with good biodegradability and renewable behavior. However, castor oil as a green lubricant has a few shortcomings, such as a low viscosity index and low oxidative stability due to the presence of unsaturated bonds. The temperature affects the lubrication performance of castor oil. In the present study, the lubrication performance and viscosity behavior of castor oil lubricating the friction pair of a steel ball and a nickel–titanium (NiTi) alloy disk were systematically investigated under different temperatures. The results show that the lubrication performance of castor oil is influenced by temperature due to the fact that the viscosity of castor oil varies with the temperature. The coefficient of friction (CoF) of castor oil is as super-low as 0.076 at a temperature of 40°C, but is relatively high at other temperatures. The factors affecting the lubrication performance were investigated, and a possible antifriction mechanism is proposed in this study.

A review on tribological performance of ionic liquids as additives to bio lubricants

All the moving components in an internal combustion engine require a lubricant that allows smooth sliding and/or rolling of interacting surfaces. Lubricant not only minimizes the friction and wear but also dissipates the heat generated due to friction and removes debris from the area of contact. Environmental concerns, decreasing mineral oil reserves and difficult disposal of nonbiodegradable conventional lubricants have urged the researchers to shift towards environmental-friendly lubricants. Number of tribological studies carried out in the past have proved that ionic liquid-based bio-lubricants are sustainable and biodegradable alternative to mineral oils. This paper presents a brief review of properties of ionic liquids and their ability to reduce friction and wear between the interacting surfaces. Tribological performance and compatibility of ionic liquids with various base-oils have been compared under boundary lubrication. The results reveal that phosphonium-based ionic liquids namely tetra-decyl tri-hexyl phosphonium bis(2,4,4-trimethylpentyl) phosphinate (P66614)i(C8)2PO2 and tri-hexyl tetra-decyl phosphonium bis(2-ethylhexyl) phosphate (P-DEHP) are more suitable for tribological applications. Since, ionic liquids can be tailored according to the application and millions of combinations are possible therefore, there is a need to summarize the published data in a more systematic and logical way.

Performance evaluation of bio-lubricants in strip drawing and deep drawing of an aluminium alloy

ABSTRACT With the increasing awareness and concerns towards the detrimental impact of mineral-oil-based lubricants, a step forward is crucial to replace them with benign environment-friendly lubricants. Bio-lubricants, due to their intrinsic lubricant properties attributed to the presence of long chain fatty acids, have an immense potential to be utilised as green lubricants and could be promising substitutes for the mineral oil-based lubricants. In this work, the performance evaluation of three bio-lubricants (Cottonseed, Karanja, and Jatropha oils) is carried out by applying in strip drawing and deep drawing experiments. The strip draw tests are conducted to determine the coefficient of friction, whereas the effectiveness of the bio-lubricants in the deep drawing are examined evaluating the drawability, thinning, drawing load and surface finish. The obtained results are compared with a mineral-oil-based lubricant and a water soluble paste. All the three bio-lubricants are found to perform well in comparison to mineral-oil-based lubricant in terms of resulting friction coefficient, drawability, and thinning at low normal pressure. Cottonseed oil is found to be better than the other two bio-lubricants. However, with an increase in normal pressure, the lubricating performance of bio-lubricants decreased significantly which can be addressed by adding extreme pressure additives.

Moringa polyesters as eco-friendly lubricants and its blends with naphthalenic lubricant

Due to the toxicity and low biodegradability, mineral lubricants have been sharing space with green lubricants. Moringa oleifera can grow naturally in dry regions with subtropical climates and the oil, rich in unsaturated compounds (79.87 %), may be a potential feedstock for fuel and lubricant base stocks. Moringa oil was hydrolyzed and then esterified with polyols, trimethylolpropane (MTMPE) and pentaerythritol (MPEE), in the temperature range of 130–140 °C. P-toluene sulfonic acid (p-TSA) was used as the catalyst. The products obtained were characterized using 1H and 13C NMR, IR, and mass spectral techniques. The main physicochemical properties, the thermal behavior and toxicity against Artemia salina of products were evaluated. In addition, blends with the naphthenic lubricant, NH10, were prepared with 20 %, 35 %, and 50 % of the moringa esters. The synthesized samples have high viscosity indices (VI = 170) and they were found to be non-toxic against A. salina (LC50>1000 ppm). MTMPE presented higher thermal stability and showed a melting point of -38.5 °C, which reveals its potential for applications in very low temperatures. Blends showed high viscosity indices and reduced toxicity compared to pure NH10. The study revealed that moringa esters are interesting to be applied as environmental friendly lubricants or additives.

Machining performance of Inconel-718 alloy under the influence of nanoparticles based minimum quantity lubrication grinding

Abstract Environmental and health problems associated with the conventional mineral-based cutting fluids has enhanced the quest of researchers to search for environment-friendly lubrication techniques. Minimum Quantity Lubrication (MQL) is the latest technique developing to reduce the use of coolants in machining. In the present work grinding of Inconel-718 (Ni-Cr alloy) has been examined under the influence of Al2O3 based Nanofluid Minimum Quantity Lubrication (NFMQL) technique using vegetable oils as the base oils in view of environmental conscious grinding. The grinding performance of Inconel-718 was evaluated in terms of surface roughness, grinding energy, cutting forces, temperature, and G-ratio. Nanofluids were prepared by adding 0.5 wt% and 1 wt% Al2O3 nanoparticles to the sunflower and rice-bran vegetable oils. From the results, it is observed that Al2O3 based nanofluid MQL with sunflower as base oil has given better results with respect to G-ratio, grinding energy, surface roughness, and coefficient of friction. Better value of surface roughness (0.5 μm) is achieved with 0.5 wt% concentration of nano-particles, whereas G-ratio (1.52), grinding energy(32.91 J/mm3) and tangential forces improved under nanofluid MQL condition with 1 wt% concentration of nanoparticles as compared to flood cooling. This might be due to the fact that while nanofluids flow through the wheel-workpiece interface, it results in the formation of a lubrication film that acts as ball bearing and reduces the sliding friction. Thus vegetable oils with the appropriate amount of Al2O3 nano-particles can give sufficient tribological properties with the environment and economic advantages.

Synthesis of Estolide Ester and Amide from Acetylated Polyhydroxy Estolide for Lubricant Base Oil

AbstractPlant oil‐based lubricants are used as alternative for mainstream petroleum‐based lubricants mainly because they are known to be environmentally friendly. However, their market acceptance is limited by their high pour point and poor oxidation stability. This study presents an approach to make biodegradable lubricant from oleic acid that shows low pour point and satisfactory oxidation stability. A mixture of estolides with acetyl and hydroxy functionalities is prepared from reaction between oleic acid, acetic acid, and hydrogen peroxide. Subsequently, the hydroxy groups of estolide are end‐capped with lauric acid to improve oxidation stability. Further reaction with alcohol and amine yielded estolide ester and amide, respectively. Physicochemical properties evaluation of prepared estolide ester and amide reveal that they have properties comparable to commercial samples in terms of pour point, oxidation stability, viscosity index, and antiwear. Furthermore, both estolide ester and amide are found to be readily biodegradable, which support their use as environmental friendly lubricant. Therefore, the inferior properties of plant oil‐based lubricants can be resolved by chemical modifications that yield specific estolide ester and amide with excellent properties suitable for lubricants.Practical Applications: The prepared estolide ester and amide have good potential to be used as lubricant base oil for environmentally acceptable lubricants due to their inherent readily biodegradability nature and excellent lubricant properties.

Predictive modelling and parametric optimization of minimum quantity lubrication–assisted hobbing process

This paper focuses on parametric analysis, modelling, and parametric optimization of minimum quantity lubrication–assisted hobbing (MQLAH) using an environment-friendly lubricant for manufacturing superior quality spur gears. Influences of hob cutter speed, axial feed, lubricant flow rate, air pressure, and nozzle angle on the deviations in total profile, total lead, total pitch and radial runout, and flank surface roughness parameters were studied by conducting 46 experiments using the Box-Behnken method of response surface methodology. Results revealed that the effect of air pressure is negligible but other parameters have a significant impact on the considered responses. A back propagation neural network (BPNN) model was developed to predict microgeometry deviations and flank surface roughness values of the MQLAH-manufactured spur gears. The BPNN-predicted results are found to be very closely agreeing with the corresponding experimental results with a mean square error as 0.0063. A real-coded genetic algorithm (RCGA) was used for parametric optimization of MQLAH process for simultaneous minimization of microgeometry deviations and flank surface roughness. Standardized values of the optimized parameters were used to conduct confirmation experiments whose results had very good closeness with RCGA-computed and BPNN-predicted values and produced spur gears of superior quality. This study proves MQLAH to be a potential sustainable replacement of conventional flood lubrication–assisted hobbing for manufacturing cylindrical gears of better quality.

Ultralow friction of PVD TiN coating in the presence of glycerol as a green lubricant

Recently, glycerol has raised great interest among researchers as an environmentally-friendly lubricant. Low friction, even super-lubricity, can be achieved when glycerol is used with diamond-like carbon coatings. Though TiN coatings are currently widely used in improving the tribological performance of forming tools, cutting tools, and machine elements, no literature exists on the tribological performance of a PVD TiN coating under glycerol lubrication. This paper investigates the combination of TiN coatings with glycerol. The results show that glycerol exhibits excellent lubrication performance, which is stronger in the steel/TiN than in the steel/steel tribopair. The action mechanism of glycerol in steel/TiN tribopair is also proposed.

A novel approach in developing environment-friendly bio-lubricant from coconut oil, mustard oil and its methyl esters

The environmental issues caused by synthetic lubricant oils necessitate the need for an environment-friendly lubricant. In this study, a novel approach is proposed for developing an environment-friendly bio-lubricant by blending mustard oil, coconut oil and its methyl esters. Properties of the bio-lubricant are studied and compared with commercial ISO VG 32 oil. The best among various blends prepared are selected based on a decision matrix. The results revealed that this method helps in pour point depression and also in achieving excellent oxidative stability as compared to the base vegetable oil. The newly formulated oil has a pour point lower than that of commercial oil and is found to be highly biodegradable. The anti-wear characteristics of the oil are improved using boric acid, and the viscosity of the oil is improved using ethyl vinyl acetate for meeting the industrial standards. The newly formulated oil complies with industrial standards and can be used as biodegradable lubricant oil.

Effect of Production Rate on Lubrication Performance of Environmentally-Friendly Lubricant in Combined Forward-Can and Backward-Can Cold Extrusion Test of Aluminum Alloy

Effect of Production Rate on Lubrication Performance of Environmentally-Friendly Lubricant in Combined Forward-Can and Backward-Can Cold Extrusion Test of Aluminum Alloy

Experimental analysis of tribological performance of palm oil blended with hexagonal boron nitride nanoparticles as an environment-friendly lubricant

Expanded worries about the ecological harm brought about by mineral oil-based lubricants have made a developing worldwide trend of advancing vegetable oil as base oil. Along these lines, this paper presents the tribological performance of palm oil blended with hexagonal boron nitride (hBN) nanoparticles as an environment-friendly lubricant. The hBN nanoparticles were 70 nm and were blended with the palm oil at varying concentrations that ranged between 0 and 0.5 vol.%. The samples were blended by using the sonication technique, with the help of an ultrasonic homogenizer. Thereafter, the tribological test was conducted using a four-ball tribometer as indicated by engineering standard testing method (ASTM D4172-94). The surface morphology and chemical composition of the worn surfaces were observed using the scanning electron microscopy (SEM) installed with energy-dispersive X-beam spectroscopy (EDX). Results showed that when hBN nanoparticles were blended with palm oil, the unsteady-state coefficient of friction (COF) was promptly changed to a steady-state condition during the running-in period. However, the higher concentration of hBN nanoparticles causes higher COF. Furthermore, 0.1 vol.% of the hBN nanoparticles in palm oil exhibited lower COF and wear rate compared with the palm oil alone and commercially available engine oil SAE 15W40.

Performance of polymeric viscosity improver as bio-lubricant additives

Purpose The purpose of this paper is to study the influence of polymeric viscosity improver on the tribological performance of palm kernel methyl ester (PKME). Design/methodology/approach Tribological performances of the PKME added with the various concentration of ethylene-vinyl acetate copolymer (EVA) were evaluated using four-ball tribotester under extreme pressure condition. The morphologies of the worn surfaces were observed by using the optical microscope. Findings The addition of polymeric viscosity improver (EVA copolymer) has produced positive results towards the tribological properties of PKME. In total, 4 per cent of EVA copolymer is found as the optimum concentration by improving the friction reducing properties and anti-wear behaviour due to the formation of film thickness between two rubbing surfaces. Originality/value This work might contribute to the development of vegetable oils as a new source of environmental-friendly lubricant.

Evaluating the Rheological and Tribological Behaviors of Coconut Oil Modified with Nanoparticles as Lubricant Additives

In metal-forming processes, the use of lubricants for providing desirable tribological conditions at the tool–workpiece interface is critical to increase the material formability and prolonging tool life. Nowadays, the depletion of crude oil reserves in the world and the global concern in protecting the environment from contamination have renewed interest in developing environmentally-friendly lubricants derived from alternative sources such as vegetable oils. In the present study, the rheological and tribological behavior of coconut oil modified with nanoparticle additives was experimentally evaluated. Two different nanoparticle additives were investigated: Silicon dioxide (SiO2) and copper oxide (CuO). For the two conditions, nanoparticles were dispersed at different concentrations within the coconut oil. The effects of concentration and shear rate on the viscosity were evaluated and the experimental data was compared with conventional models. A custom-made tribotester was used to evaluate the effect of concentration on the tribological performance of the nano-lubricants. The experimental results showed that wear volume loss was lowered by 37% and 33% using SiO2 and CuO nanoparticles, respectively. Furthermore, the addition of SiO2 and CuO nanoparticles decreased the coefficient of friction (COF) by 93.75% and 93.25%, respectively, as compared to coconut oil without nanoparticles.