Ethoxylated Amine Friction Modifiers and ZDDP

Dawczyk, Joanna; Russo, Joe; Spikes, H. A.

doi:10.1007/s11249-019-1221-4

Cited by 26 publications

(20 citation statements)

References 35 publications

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“…It is generally presumed that in order to most effectively reduce friction, OFMs must form quite dense monolayers so as to enable lateral van-der Waal attraction between adjacent, vertically oriented, hydrocarbon chains [2][3][4]. However, some recent work has suggested that even loosely packed films may significantly reduce friction [5,6]. OFM films form extremely rapidly, limited only by the rate of diffusion of their molecules from lubricant to surface and subsequent organisation [7].…”

Section: Friction Modifier (Fm) Additivesmentioning

confidence: 99%

Friction Modifier Additives, Synergies and Antagonisms

2019

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There is growing interest in reducing friction in lubricated machine components to thereby increase the energy efficiency of machines. One important way to minimise friction is to employ friction modifier additives to reduce friction in thin film boundary lubrication conditions. There are currently three main types of friction modifier additive, organic friction modifiers, oil soluble organomolybdenum friction modifiers and functionalised polymers. In common practice, a single such additive is generally employed in a formulated lubricant, but it is of interest to explore whether combinations of two friction modifier additives may prove beneficial. In this study, the performance of eight commercial friction modifier additives spanning all three main types was first measured in three quite different friction tests. The aim was to identify the contact conditions under which each additive was most effective. Additive solutions in both a base oil and a formulated engine oil were investigated. In general, functionalised polymers were most beneficial in sliding-rolling contacts, while oil soluble organomolybdenum friction modifiers worked best in severe, reciprocating sliding conditions. However, all friction modifier additive response was strongly affected by the other additives present in formulated engine oils. The friction performance of combinations of friction modifier additives was then explored. When two different friction modifiers additives were combined in solution, several possible outcomes were observed. The most common was for one of the additives to predominate, to give friction that was characteristic of that additive alone, while in some cases friction lay between the values produced by either additive on its own. In a few cases the additives behaved antagonistically so that the combination gave higher friction than either additive by itself. In a few cases true synergy was observed, where a combination of two additives produced lower friction in a given test that either individual component at the same overall concentration. Another, and possibly more important synergy could also occur, however, when a pair of FMs worked more effectively than either individual additive over the range of test conditions present in different friction tests. This study suggests that optimal combinations of FMs may provide a means of reducing boundary friction and thus increasing the efficiency of machines, especially if the latter contain a range of lubricated machine components that operate with different types of tribological contacts.

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Section: Friction Modifier (Fm) Additivesmentioning

confidence: 99%

Friction Modifier Additives, Synergies and Antagonisms

2019

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“…Even though they can be of interest for various applications 64,68 , the molecules have been chosen with a special attention to be representative of the typical additives used in various industrial lubricant applications such as thermal engine, metal working, gear box… Fatty ethoxylated amines and fatty acid derivatives are often used as organic friction modifiers 4,69,70 whereas fatty amines are good anticorrosion additives 4 . Phosphates are presenting good extreme-pressure properties, but can also be used as detergents, just like fatty acids.…”

Section: Studied Moleculesmentioning

confidence: 99%

(Dis)Similarities of adsorption of diverse functional groups over alumina and hematite depending on the surface state

Blanck

Martí

Loehlé

et al. 2021

The Journal of Chemical Physics

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To accelerate the conversion to more sustainable lubricants, there is a need for an improved understanding of the adsorption at the solid/liquid interface. As a first step, the DFT computed adsorption energies can be used to screen the ability of additives to cover a surface. Analogously to what has been found in catalysis with the universal scaling relations, we investigate here if a general universal ranking of additives can be found, independently of the surface considered. We divided our set of 25 diverse representative molecules into aprotic and protic molecules. We compared their adsorption over alumina and hematite, which are models of surface oxidized aluminum and steel, respectively. The adsorption energy ranking of our set is not strongly affected by alumina hydration.In contrast, adsorption on hematite is more strongly affected by hydration since all exposed Fe Lewis acid sites are converted into hydroxylated Brønsted basic sites. However, the ranking obtained on hydrated hematite is close to the one obtained on dry alumina, paving the road to a fast screening of additives. In our library, protic molecules are more strongly adsorbed than non-protic molecules. In particular, methyl and dimethyl phosphates are the most strongly adsorbed ones, followed by Nmethyldiethanolamine, succinimide and ethanoic acid. Additives combining these functional groups are expected to strongly adsorb at the solid/liquid interface and, therefore, likely to be relevant components of lubricant formulations.

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“…These molecular films are important in a variety of application, from tribology to corrosion. [92][93][94] Typically, fatty amines are used as lubrication additives to beneficiate from their anti-corrosion and friction modification abilities.…”

Section: Film Structurationmentioning

confidence: 99%

Transferable Gaussian Attractive Potentials for Organic/oxide Interfaces

Rey¹,

Blanck²,

Clabaut³

et al. 2021

Preprint

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Organic/oxide interfaces play an important role in many areas of chemistry, and in particular for lubrication and corrosion. Molecular dynamics simulations are the method of choice for providing complementary insight to experiments. However, the force fields used to simulate the interaction between molecules and oxide surfaces tend to capture only weak physisorption interactions, discarding the stabilizing Lewis acid/base interactions. We here propose an improvement of the usual molecular mechanics description (based on Lennard-Jones and electrostatic interactions) by addition of an attractive Gaussian potential between reactive sites of the surface and heteroatoms of adsorbed organic molecules, leading to the GLJ potential. The interactions of four oxygenated and four amine molecules with the typical and widespread hematite and γ-alumina surfaces are investigated. The total RMSD for all probed molecules decreases from 29.2 to 5.7 kcal/mol, and the corresponding percentage from 107.4 to 22.6% over hematite, while on γ-alumina the RMSD decreases from 21.5 to 7.6 kcal/mol, despite using a single parameter for all five chemically inequivalent surface aluminum atoms. Applying GLJ to the simulation of n-octadecanamine and N-tetradecyldiethanolamine adsorbed films on hematite and alumina respectively demonstrates that mobility of the surfactants is overestimated by the common LJ potential, while GLJ shows a strong structuration and slow dynamics of the surface films, as could be expected from the first-principles adsorption energies for model head-groups.

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Ethoxylated Amine Friction Modifiers and ZDDP

Cited by 26 publications

References 35 publications

Friction Modifier Additives, Synergies and Antagonisms

Friction Modifier Additives, Synergies and Antagonisms

(Dis)Similarities of adsorption of diverse functional groups over alumina and hematite depending on the surface state

Transferable Gaussian Attractive Potentials for Organic/oxide Interfaces

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