Principles of synthesis of viscosity index improvers of the poly(alkyl methacrylate) type

Négrell

Robin

et al. 2019

J Americ Oil Chem Soc

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.

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

Négrell

Robin

et al. 2019

J Americ Oil Chem Soc

“…For many decades, the VI of mineral oils that have low VI has been improved by adding polymeric viscosity index improvers (VII) in lube oils, which ensured a proper oil viscosity at high temperature (Bartz, ; Bataille et al, ; Lariviere et al, ). The most commonly used polymers in lubricant applications are poly(alkyl methacrylate)s (PMA) (Akhmedov and Buniyat‐Zade, ; Ghosh et al, ; Neveu et al, ). Such polymers demonstrate an incomplete solubility compared to hydrocarbon polymers in mineral oils due to their polar ester functions and are known to raise the viscosity of the mineral oil proportionately more at high temperatures than at low temperatures, which results in the lube oil VI improvement (Akhmedov and Buniyat‐Zade, ; Ghosh et al, ; Jukic et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…For many decades, the VI of mineral oils that have low VI has been improved by adding polymeric viscosity index improvers (VII) in lube oils, which ensured a proper oil viscosity at high temperature (Bartz, 2000;Bataille et al, 1994;Lariviere et al, 2000). The most commonly used polymers in lubricant applications are poly(alkyl methacrylate)s (PMA) (Akhmedov and Buniyat-Zade, 1993;Ghosh et al, 2017;Neveu et al, 2012). Such polymers Supporting information Additional supporting information may be found online in the Supporting Information section at the end of the article.…”

Section: Introductionmentioning

confidence: 99%

“…demonstrate an incomplete solubility compared to hydrocarbon polymers in mineral oils due to their polar ester functions and are known to raise the viscosity of the mineral oil proportionately more at high temperatures than at low temperatures, which results in the lube oil VI improvement (Akhmedov and Buniyat-Zade, 1993;Ghosh et al, 2015;Jukic et al, 2007). Their widely reported mechanism of action is based on the coil polymer expansion in mineral oil, which is assimilated to the gradual improvement of polymer solubility in temperature and, therefore, to a gradual polymer-thickening power in oil Müller, 1978;Selby, 1958).…”

Section: Introductionmentioning

confidence: 99%

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Epoxidized Oleic Acid‐Based Polymethacrylates as Viscosity Index Improvers

Lapinte

Négrell

et al. 2019

J Americ Oil Chem Soc

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.

“…In order to limit the decrease of viscosity with temperature, mineral oils are generally blended with viscosity index improver (VII) additives which have the ability to expand the base oil operating temperature range. 1,2 These additives are well-known to reduce the lube oils viscosity-temperature dependency but also their cold flow properties. 3 The main polymers used for this application are poly(alkyl)methacrylates (PMA)s. They typically have long oil soluble hydrocarbon (nonpolar) tails and smaller hydrophilic (polar) head groups which provide them specific conformation in mineral oils according to the temperature.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of plant oil-based amide copolymethacrylates and their use as viscosity index improvers

European Polymer Journal

Mohring

Lapinte

et al. 2018

Polymeric materials derived from fatty acids (FA)s were synthesized through free radical polymerization and evaluated as viscosity index improvers (VII) in an organic triglyceride lube oil (OTO). For this purpose, various FA-based copolymers were designed to own a reduced solubility at low temperature in OTO which can be gradually improved by increasing temperature. Different fatty amide methacrylates were chosen for their poorly oil-miscible repeating units while fatty ester methacrylates, 2-(methacryloyloxy)ethyl oleate (MAEO) and 2-(methacryloyloxy)ethyl 4-(dodecylthio)oleate (MAEO SC12 ), were used as oil-miscible comonomers for providing copolymers with a minimum of solubility in the lube oil. All copolymers were synthesized with a 50:50 molar feed ratio and were fully characterized through 1 H NMR, SEC, DSC, and TGA analyses. Then, rheological study of oil-copolymer blends revealed that copolymers containing -NH function were able to have a higher impact on oil viscosity at high than at low temperatures suggesting the coil copolymer expansion.