Urea (Polyurea) Greases

Lyadov, A. S.; Maksimova, Yu. M.; Shakhmatova, A. S.; Kirillov, V. V.; Parenago, O. P.

doi:10.1134/s1070427218060010

Cited by 18 publications

(8 citation statements)

References 11 publications

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“…In history, the use of natural materials as lubricating greases was widely carried out since the first mention of the topic, dating back to Ancient Egypt. Nonetheless, the discovery of metal-based soaps and mineral and synthetic oils crucially changed the course of lubricating grease production (see Table 11 ) [ 277 ].…”

Section: Lignocellulose-based Polyurethanesmentioning

confidence: 99%

Lignocellulosic Materials for the Production of Biofuels, Biochemicals and Biomaterials and Applications of Lignocellulose-Based Polyurethanes: A Review

2022

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The present review is devoted to the description of the state-of-the-art techniques and procedures concerning treatments and modifications of lignocellulosic materials in order to use them as precursors for biomaterials, biochemicals and biofuels, with particular focus on lignin and lignin-based products. Four different main pretreatment types are outlined, i.e., thermal, mechanical, chemical and biological, with special emphasis on the biological action of fungi and bacteria. Therefore, by selecting a determined type of fungi or bacteria, some of the fractions may remain unaltered, while others may be decomposed. In this sense, the possibilities to obtain different final products are massive, depending on the type of microorganism and the biomass selected. Biofuels, biochemicals and biomaterials derived from lignocellulose are extensively described, covering those obtained from the lignocellulose as a whole, but also from the main biopolymers that comprise its structure, i.e., cellulose, hemicellulose and lignin. In addition, special attention has been paid to the formulation of bio-polyurethanes from lignocellulosic materials, focusing more specifically on their applications in the lubricant, adhesive and cushioning material fields. High-performance alternatives to petroleum-derived products have been reported, such as adhesives that substantially exceed the adhesion performance of those commercially available in different surfaces, lubricating greases with tribological behaviour superior to those in lithium and calcium soap and elastomers with excellent static and dynamic performance.

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Section: Lignocellulose-based Polyurethanesmentioning

confidence: 99%

Lignocellulosic Materials for the Production of Biofuels, Biochemicals and Biomaterials and Applications of Lignocellulose-Based Polyurethanes: A Review

2022

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“…Aside from soap greases, another slightly less popular alternative is polyurea (PU) greases. PU greases offer comparable properties to lithium soap greases with an upper operating limit temperature of 180

^{°}

C, strong water resistance, thermal and shearing stability 29 . Ren et al performed a comparative study between lithium‐complex and PU greases regarding their corrosion resistance and lubrication performance.…”

Section: Application Of Greases In Ev Industry and Current Challengesmentioning

confidence: 99%

Latest developments in designing advanced lubricants and greases for electric vehicles—An overview

Shah¹,

Gashi²,

Rosenkranz

2022

Lubrication Science

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According to the Environmental Protection Agency, transportation is the largest contributor of greenhouse gas emissions (28% of total emissions). Electric vehicles have remarkably grown in popularity and represent a greener future for the automotive industry. This growth has prompted lubricant and grease technology to adapt to an entirely new environment, which is exposed to new factors including external electric currents/fields and extreme temperatures and pressures originating from electric motors and power electronics. Consequently, novel lubricants and greases need to be developed and explored to ultimately improve fuel efficiency and performance. Nano-additives have offered exceptional opportunities to enhance electrical, thermal and tribological properties of the lubricants and greases used. It is thus vital to fully explore and understand the effects of nanoparticles' addition to lubricants and greases, as well as the mechanisms by which improvements are obtained. This perspective summarises the recent trends of developing lubricants and greases for electric vehicles.

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“…Therefore, the wall effect is significant for the formation of oil film [34]. The lone pair of nitrogen atoms in the thickener allows the thickener to be easily absorbed on the worn surface for enhancing grease adhesion, and promoting the appearance of a tribo-chemical reaction film [6]. The tribo-chemical reaction film was formed on the worn surface during the repeated sliding process, which enhanced the friction-reducing and anti-wear performance.…”

Section: Effect Of Thickener Component On Lubrication Processmentioning

confidence: 99%

“…Polyurea grease (PUG) is a potential grease that accounts for a large proportion of the high-end grease market. Compared to other greases, PUG has advantages such as oxidation stability, high/lowtemperature application, mechanical stability, antirust properties, and colloidal stability [6][7][8]. As a kind of a non-soap based grease, PUGs are free from the catalytic oxidation of soap base grease, thereby prolonging their service life at high temperatures [9].…”

Section: Introductionmentioning

confidence: 99%

Improving the lubrication and anti-corrosion performance of polyurea grease via ingredient optimization

Ren

Sun

et al. 2020

Friction

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Thickener formulation plays a significant role in the performance characteristics of grease. The polyurea greases (PUGs) were synthesized using mineral oil (500SN) as the base oil, and by regulating the reaction of diphenylmethane diisocyanate (MDI) and different organic amines. The as-prepared PUGs from the reaction of MDI and cyclohexylamine/p-toluidine exhibit the optimum physicochemical and friction-wear properties, confirming that the regulation of thickener formulation can improve the performance characteristics of grease, including friction reduction, wear, corrosion resistance, and load-carrying capacity. The anticorrosion and lubrication properties of as-prepared PUGs depend on good sealing functions and a boundary lubrication film (synergy of grease-film and tribo-chemical reaction film), as well as their chemical components and structure.

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Urea (Polyurea) Greases

Cited by 18 publications

References 11 publications

Lignocellulosic Materials for the Production of Biofuels, Biochemicals and Biomaterials and Applications of Lignocellulose-Based Polyurethanes: A Review

Lignocellulosic Materials for the Production of Biofuels, Biochemicals and Biomaterials and Applications of Lignocellulose-Based Polyurethanes: A Review

Latest developments in designing advanced lubricants and greases for electric vehicles—An overview

Improving the lubrication and anti-corrosion performance of polyurea grease via ingredient optimization

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