Review of Viscosity Modifier Lubricant Additives

Martini, Ashlie; Ramasamy, Uma Shantini; Len, Michelle

doi:10.1007/s11249-018-1007-0

Cited by 116 publications

(120 citation statements)

References 91 publications

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“…According to the calculation method of the VI, lubricants with a high VI exhibit a low viscosity variation with temperature and are generally preferred in most machines. Therefore, in order to provide performing lubricant, base oils are generally formulated with specific high‐molecular weight polymer additives known as viscosity index improvers (VII)s (Almeida et al, ; Martini et al, ; Rattan and Parihar, ). The addition of these polymers, which display viscosity thickening power as a result of their high molecular weight, is able to minimize viscosity variation in temperature, increase the VI, and thus, widen the application temperature range of lubricants.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Alkyl Sulfur‐Functionalized Oleic Acid‐Based Polymethacrylates and Their Application as Viscosity Index Improvers in a Mineral Paraffinic Lube Oil

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Négrell

Robin

et al. 2019

J Americ Oil Chem Soc

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This work describes the synthesis of alkyl sulfur‐functionalized polymethacrylate‐based Viscosity Index Improvers (VII) derived from oleic acid (OLA) for mineral paraffinic lubricating oils. In this strategy, OLA was first quantitatively ramified by alkyl thiols containing long aliphatic chains through thiol‐ene coupling as demonstrated by 1H NMR spectroscopy with the complete consumption of OLA internal double bonds. The resulting alkyl sulfur‐functionalized OLA‐based derivatives were methacrylated through Steglich esterification in order to afford highly suitable hydrophobic OLA‐based monomers which, as far as we know, have not been described yet in the current literature. High polymethacrylate molecular weights were reached through radical polymerization despite the long alkyl pendant chains contained in their backbones. Finally, the resulting alkyl sulfur‐functionalized OLA‐based polymethacrylates have been blended in a mineral paraffinic oil (MPO) of reference at 5 wt% and evaluated as VII. Rheological measurements revealed that polymer thickening powers were significantly improved in oil with temperature and promoted by increasing the pendant alkyl thiol contained in polymer backbones. Moreover, the viscosity index of MPO was significantly improved with the addition of both synthesized homopolymers which confirmed their efficiency as VII. In the meantime, these results have been compared with a previously reported polymer, the poly(2‐[methacryloyloxy]ethyl oleate) (PMAEO), which demonstrated a lower VII efficiency compared with its analogous polymethacrylates containing an additional alkyl chain in their pendant chains.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Alkyl Sulfur‐Functionalized Oleic Acid‐Based Polymethacrylates and Their Application as Viscosity Index Improvers in a Mineral Paraffinic Lube Oil

Lomège

Négrell

Robin

et al. 2019

J Americ Oil Chem Soc

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“…It can be noticed that despite the similar high thickening power of PMAEO on the lube oil viscosity at low and high temperatures, the polymer was still able to improve the VI of OTO. Thus, the VI should not be used as the only argument to confirm the nature of an additive as suitable VII because thickener additives also have the ability to improve the oil VI without following the coil expansion theory (Martini et al, ). Otherwise, the addition of PMAEO‐E in OTO did not affect significantly the oil VI that was increased from 156 to only 162.…”

Section: Evaluation Of the Epoxidized Oleic Acid‐based Polymers As VImentioning

confidence: 99%

Epoxidized Oleic Acid‐Based Polymethacrylates as Viscosity Index Improvers

Lomège

Lapinte

Négrell

et al. 2019

J Americ Oil Chem Soc

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This study reports two routes for the synthesis of epoxidized oleic acid (OLA)‐based polymethacrylates. The first one consisted of the synthesis followed by epoxidation of the OLA‐based methacrylate, 2‐(methacryloyloxy)ethyl oleate (MAEO), prior to its radical polymerization. In the second pathway, MAEO was first homopolymerized to afford poly(2‐(methacryloyloxy)ethyl oleate) (PMAEO) and, then, the internal double bonds of the oleate were epoxidized at different yields ranging from 20% to 100%. All polymeric structures were confirmed using 1H nuclear magnetic resonance (NMR), and characterized through size‐exclusion chromatography (SEC), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) analyses. The resulting polymers were then blended at 5 wt.% in a mineral paraffinic oil (MPO) and in a biobased organic triacylglycerol oil (OTO) to be evaluated as viscosity index improvers (VII). The partially epoxidized polymers up to 40% were soluble in MPO. According to a rheological study, the oil‐soluble epoxidized polymers resulting from the epoxidation of PMAEO exhibited a much higher influence on oil viscosities at high temperatures than at low temperatures compared to the low‐epoxidized PMAEO molecular weight obtained by the first strategy. Additionally, the viscosity indices of both lubricating oils were significantly improved with the addition of the epoxidized OLA‐based polymers resulting from the epoxidation of PMAEO, which confirmed their efficiency as VII.

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“…These attempts are based on polymeric and small-molecule candidates as will be reviewed and highlighted in this chapter. The mechanisms behind the thickening of any solvent depend on polymer coil expansion, intermolecular interactions, entanglement, aggregation (affected by the polymer molecular weight distributions), and self-assembly and indirectly through the effect of polymer molecules on nearby solvent molecules [5].…”

Section: Introductionmentioning

confidence: 99%

Direct Gas Thickener

Hinai¹,

Myers²,

Wood³

et al. 2019

Enhanced Oil Recovery Processes - New Technologies

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Direct gas thickening technique has been developed to control the gas mobility in the miscible gas injection process for enhanced oil recovery. This technique involves increasing the viscosity of the injected gas by adding chemicals that exhibit good solubility in common gasses, such as CO 2 or hydrocarbon (HC) solvents. This chapter presents a review of the latest attempts to thicken CO 2 and/or hydrocarbon gases using various chemical additives, which can be broadly categorised into polymeric, conventional oligomers, and small-molecule self-interacting compounds. In an ideal situation, chemical compounds must be soluble in the dense CO 2 or hydrocarbon solvents and insoluble in both crude oil and brine at reservoir conditions. However, it has been recognised that the use of additives with extraordinary molecular weights for the above purpose would be quite challenging since most of the supercritical fluids are very stable with reduced properties as solvents due to the very low dielectric constant, lack of dipole momentum, and low density. Therefore, one way to attain adequate solubility is to elevate the system pressure and temperature because such conditions give rise to the intermolecular forces between segments or introduce functional groups that undergo self-interacting or intermolecular interactions in the oligomer molecular chains to form a viscosity-enhancing supramolecular network structure in the solution. According to this review, some of the polymers tested to date, such as polydimethylsiloxane, polyfluoroacrylate styrene, and poly(1,1-dihydroperfluorooctyl acrylate), may induce a significant increase of the solvent viscosity at high concentrations. However, the cost and environmental constraints of these materials have made the field application of these thickeners unfeasible. Until now, thickeners composed of small molecules have shown little success to thicken CO 2 , because CO 2 is a weak solvent due to its ionic and polar characteristics. However, these thickeners have resulted in promising outcomes when used in light alkane solvents.

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Review of Viscosity Modifier Lubricant Additives

Cited by 116 publications

References 91 publications

Synthesis of Alkyl Sulfur‐Functionalized Oleic Acid‐Based Polymethacrylates and Their Application as Viscosity Index Improvers in a Mineral Paraffinic Lube Oil

Synthesis of Alkyl Sulfur‐Functionalized Oleic Acid‐Based Polymethacrylates and Their Application as Viscosity Index Improvers in a Mineral Paraffinic Lube Oil

Epoxidized Oleic Acid‐Based Polymethacrylates as Viscosity Index Improvers

Direct Gas Thickener

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