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The purpose of this study is to improve the tribological characteristics of cotton-biolubricant by adding nanoparticles at extreme pressure (EP) conditions in comparison with commercial lubricant SAE-40.

This research involved the synthesis of cotton-biolubricant by transesterification process and then the addition of nanoparticles in it to improve anti wear (AW)/EP tribological behavior. SAE-40 was studied as a reference commercial lubricant. AW/EP characteristics of all samples were estimated by the four-ball tribo-tester according to the American Society for Testing and Materials D2783 standard.

The addition of 1-Wt.% TiO₂ and Al₂O₃ with oleic acid surfactant in cotton-biolubricant decreased wear scar diameter effectively and enhanced the lubricity, load-wear-index, weld-load and flash-temperature-parameters. This investigation revealed that cotton-biolubricant with TiO₂ nano-particle additive is more effective and will help in developing new efficient biolubricant to replace petroleum-based lubricants.

Cotton biolubricant with TiO₂ nano-particles appeared as an optimistic solution for the global bio-lubricant market.

No one has not studied the cotton biolubricant with nanoparticles for internal combustion engine applications at high temperature and EP conditions.

Depleting reserves of crude oils and their adverse environmental effects have shifted focus toward environment friendly and biobased lubricant base oils. Natural oils and fats act as good lubricants but they have low oxidation and thermal stability which makes them unsuitable for modern day uses. This paper aims to produce trimethylolpropane ester biolubricant from cottonseed oil and study the effects of its use in spark ignition (SI) engines.

In this work, cottonseed oil is converted to TMP lubricant by a two-step based catalyzed esterification. The lubricants thermophysical properties are then analyzed and a 20% blend with synthetic poly-alpha olefin is used in an spark ignition engine.

The produced lubricant has viscosity @100^oC of 4.91 cSt, a viscosity index of 230 and a flash point of 202^oC. When used as a 20% blend in a petrol engine, the rate of oil deterioration was reduced by 18%, however, the overall wear increased by 6.7%. However, this increase is offset by its improved environmental impacts.

In its current state, such a biolubricant can be used as an additive to most commercially available lubricants to improve oil deterioration characteristics and environmental impact. However, further work on improving biolubricant’s wear characteristics is needed for the complete replacement of mineral oil-based lubricants.

The purpose of this study is to evaluate the potentials of nano-additives in enhancement of oxidation and thermal stability of biolubricants thereby, improving the resistance of dispersed nanolubricants to thermal degradation under elevated temperature.

This study evaluates the oxidation stability and tribological performance of nano-enhanced biolubricants. Graphene and maghemite nanoparticles at 0.1% volume concentration were dispersed into coconut oil. Oxidation stability was analysed using a thermal analyser to understand the effect of nano-additives on thermal degradation of lubricants under increasing temperature. In addition, tribological performance and viscosity of the tested lubricants were evaluated using a four-ball friction tester and viscometer according to American Society for Testing and Materials standards.

The results reveal that the oxidation stability of biolubricants dispersed with nano-additives improves due to delayed thermal degradation. The nano-enhanced biolubricants’ oxidation onset temperature was delayed by 18.75 °C and 37.5 °C, respectively, for maghemite (MGCO) and graphene (XGCO) nanolubricants. This improvement imparts the performance viscosity and tribological performance positively. For graphene-enhanced nanolubricant, 10.4% and 5.6% were reduced, respectively, in coefficient of friction (COF)and wear scar diameter (WSD), whereas 3.43% and 4.3% reduction in COF and WSD, respectively, for maghemite-enhanced nanolubricant compared with coconut oil. The viscosity index of nanolubricants was augmented by 7.36% and 13.85%, respectively, for maghemite and graphene nanolubricants.

The excellent performance of nanolubricants makes them suitable candidate as sustainable lubricants for machining with regard to environmental benefits and energy saving.

The effect of graphene and maghemite nanoparticles on the oxidation stability and tribological performance of biolubricants has been investigated. It is an original work and yet to be published elsewhere.

This study aims to introduce a novel technique which helped in quantifying the wear performance of a roller chain which was lubricated by using the palm oil-based hexagonal boron nitride (hBN) nanoparticles (nano-biolubricant).

The efficiency of the nano-biolubricant was evaluated by using a custom-made roller chain tribometer, at different resistance torque values at a constant speed and running time. Prior to the test, 2 different lubrication conditions were applied. The mass loss and elongation behaviour of a roller chain was selected as a degradation metric for monitoring the amount of the chain wear. The predominant wear mechanism of a roller chain was identified by surface morphological analysis.

Regardless of the lubrication conditions, the wear performance of the roller chain was significantly increased, at increasing resistance torque values. Higher wear was noted when the roller chain was lubricated using a nano-biolubricant, however, the wear curve showed a promising high chain life. The predominant wear mechanism involved is abrasive wear.

Although an increase in the elongation during running is based on the wear between the pins and roller, none of the earlier studies quantified the wear performance of a roller chain under differing lubrication conditions. Hence, for bridging the gap, this study described a new method for measuring the wear performance of the roller chain which was lubricated using the palm oil-based hBN nanoparticles or a nano-biolubricant.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0061/

This study aims to study the tribological performance of sunflower TMP ester and silica nanoparticles additives as a biolubricant alternative to the conventional lubricants for hydrodynamic journal bearing applications.

Nanolubricants were synthesized using an ultrasonicator and a homogenizer. A pin-on-disk tribometer was used to simulate the boundary lubrication condition for hydrodynamic journal bearing application in the presence of the studied lubricants. Surface analysis of the pin (bearing material) was done using scanning electron microscopy and energy dispersive X-ray spectroscopy.

The sunflower TMP ester performed well in terms of the coefficient of friction compared to commercial lubricants, but its wear performance was poor. The silica nanoparticles improved the wear and friction performance of the sunflower TMP ester. With the addition of 1% silica nanoparticles to sunflower TMP ester, the reduction in the coefficient of friction was 27.92% and the reduction in specific wear rate was 54.79%, making it the best lubricant out of all studied lubricants.

Although there are various available studies on vegetable oil-based lubricants for hydrodynamic journal bearing applications, the studies on the use of vegetable oil-based TMP esters for hydrodynamic journal bearing applications are limited. Also, the effect of silica nanoparticles on the tribological performance of TMP esters under boundary lubrication condition has not been studied extensively in the available literature.

Lubricants impact on the environment at all stages of production, usage and disposal. The awareness and concern over the usage of petroleum‐based products and their impact on the environment have created an opportunity to produce environmentally acceptable lubricants from agricultural feedstocks. A new class of bio‐based esters derived from vegetable oils that exhibit excellent low temperature flow properties and oxidation stability are discussed. One of the major advantages of bio‐based synthetic esters in better performance at a lower cost compared to synthetic esters. This is possible due to recent advances in the biotechnology of vegetable oils and the chemical modifications that could be applied to convert these natural esters into high performance biolubricants.

The purpose of this study was to investigate the biobased (rapeseed) oil with the addition of different amounts of metal-containing additive in a steel–bronze tribological system. The additional purpose was to find the optimal value of the additive.

This paper exposes experimental results of the performance characteristics (coefficient of friction (COF), working temperature and wear) of the biolubricant based on rapeseed oil. The amount of commercial metal-containing additive in formulated lubricant was 1, 1.5, 3 and 5 wt.%. All results were compared with the results obtained for the base rapeseed oil. Two different tribometers were used, with the same tribosystem elements materials (bronze and steel). COF experiments were performed under four different normal loads and fixed sliding speed and time. Temperature and wear were continuously monitored.

Results showed that the metal-containing additive in rapeseed oil reduced all monitored characteristics. It was also found that the dependence of all characteristics on the amount of additive is nonlinear and that there is an optimal value of it.

Owing to growing environmental concerns, vegetable oil-based lubricants and other biodegradable lubricants are expanding their area of application. Currently, one of the most widely used vegetable oil is rapeseed oil. The metal-containing additive used in this study is previously investigated as an addition to mineral- and synthetic-based oils. There are very few studies that investigate its influence on the vegetable oil-based lubricants. In addition, there is no comparative investigation of its influence on several performance characteristics (COF, temperature and wear).

This paper seeks to outline the technical characteristics of certain biodegradable lubricants which can lead to potential energy savings.

Reviews the reasons for introduction of biodegradable lubricants, and describes the outcome of development and establishment of suitable range of lubricants for almost all applications.

Plant‐based lubricants have low toxicity, they are derived from crop resources, they are recognised as safer to use, and are rapidly biodegradable when spilled on to open land or into water. As such they break down to reduce pollution burden and are favoured by the Environment Agency when used near watercourses. Products have been developed now for almost all applications including hydraulics, engines, transmissions, compressors, metalworking, turbines, and for use in all industry sectors. Latest generation biolubricants, however, give additional advantages above and beyond the original concept to reduce pollution: the latest products have high levels of performance in terms of both loading and temperature. In particular, their frictional characteristics have been shown to be considerably more favourable than those for mineral oil, offering energy reduction during use.

The paper is restricted to findings based on ester‐based synthetic lubricants where the esters have been derived principally from renewable resources.

Quite apart from their environmental attributes, reduced energy consumption and therefore lower variable costs are now possible, and the concept of use of these oils to give distinct savings is becoming recognised.

This study emphasises that distinct advantages for synthetic lubricants, particularly for biodegradable synthetic ester lubricants derived from renewable resources, are now being realised.

The paper aims to investigate the effect of zinc dialkyldithiophosphate (ZDDP) on wear and extreme pressure (EP) capabilities of hazelnut oil.

A four-ball tribometer is used to study the effect of ZDDP on the antiwear (AW) and EP performance of hazelnut oil as a lubricant. The AW/EP tests are carried out following ASTM D4172 and ASTM D2783 standards. The wear mechanism of steel balls is studied by scanning electron microscope (SEM). The ZDDP is added in 1Wt.%, 2Wt.% and 3Wt.% concentration, and its presence on surfaces is indicated by Energy Dispersive X-Ray Analysis (EDX).

The maximum improvement in the wear properties for hazelnut oil is equal to 43.7% and 45.7% at 1Wt.% and 3Wt. % ZDDP, respectively. Also, the load wear index of hazelnut oil increases from 29 to 73.1 at 3Wt.% ZDDP. The improvement in AW and EP properties is attributed to the protective layer formation by ZDDP.

The paper is a novel study investigating the effect of ZDDP additive in hazelnut oil. The results could prove beneficial in making the hazelnut oil a viable replacement of mineral oils.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2020-0217/