The increasing price of barrels of oil, the global warming and other environmental problems favour the use of renewable resources to replace the petroleum based polymers used in various applications. Recently, fatty acids (FA) and their derivatives have appeared as one of the most promising candidates to afford novel and innovative biobased (co)polymers because of their ready availability, their low toxicity and their high versatility. However, the current literature mostly focused on FA-based polymers prepared by condensation polymerization or oxypolymerization while only few works have been devoted to radical polymerization due to the low reactivity of FA through radical process. Thus, the aim of this article is to give an overview of (i) the most common synthetic pathways reported in literature to provide suitable monomers from FA and their derivatives for radical polymerization, (ii) the available radical processes to afford FA-based (co)polymers and (iii) the different applications in which FAbased (co)polymers have been used since the last few years.

In this work, partially biobased methacrylate polymers with various fatty acid side chains were used as efficient polymeric viscosity modifiers for mineral paraffinic oil (MPO). Firstly, oleic, palmitic, myristic and lauric acids were functionalized with 2-hydroxyethyl methacrylate by Steglich esterification to provide suitable monomers for radical polymerization. The resulting monomer from oleic acid (2-(methacryloyloxy)ethyl oleate) was polymerized through conventional radical polymerizations and telomerization in order to evaluate the influence of the polymer molecular weight on its efficiency as a viscosity modifier. Additionally, methacrylate monomers containing different chain lengths of fatty acids were involved in reversible addition–fragmentation chain transfer polymerization to obtain polymers with similar molecular weights in order to compare their efficiency as viscosity modifiers. For this purpose, all fatty acid-based polymers were mixed at 3 wt.% in MPO and relative viscosity measurement between MPO and polymer–MPO blends was performed at various temperatures. The results demonstrated that fatty acid-based methacrylate polymers have a higher polymer contribution on MPO viscosity with increasing temperature. This specific viscosimetric behavior was related to the coil polymer chains’ expansion with temperature, which was improved by increasing the polymer molar mass and the length of dangling fatty alkyl chains hanging off polymer backbones.

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This work described the design of an efficient oleic‐acid based viscosity control additive for lubricating oils as potential alternative to petroleum poly(alkyl)methacrylates (PAMAs) additives. Hence, Poly(2‐(methacryloyloxy)ethyl oleate) (PMAEO) was synthesized by free radical homopolymerization to afford a comb‐like polymer structure similar to common PAMAs. Then, in order to evaluate its efficiency as viscosity control additive, the resulting polymer was mixed at several concentrations from 1%wt to 10%wt with different oil compositions, including a mineral paraffinic oil (MPO) and an organic triglyceride oil (OTO). For all polymer‐solution blends, relative viscosities (RV) measurements showed that addition of PMAEO in MPO had a better contribution on oil viscosity at 100°C than at 20°C (RV = 1.16 at 40°C while RV = 1.25 for 3%wt of PMAEO in MPO). These results were attributed to the coil expansion of polymer chains with increasing temperature. Additionally, rheological studies showed that addition of 3%wt of PMAEO in MPO improved the MPO cold flow properties at −30°C by decreasing the required yield stress to put the oil in motion from 310 mPa to 42 mPa. These results are in total accordance with the common viscosimetric properties of PAMAs‐based viscosity control additives at low and high temperature in mineral oils. POLYM. ENG. SCI., 59:E164–E170, 2019. © 2018 Society of Plastics Engineers

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.

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.

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.