578 research outputs found
Bio-sourced polymers
1- Why ?2- How ?3- Bio-based plastics from natural polymers4- Drop-ins: Bio-based alternative to fossil-based polymers5- Smart drop-ins: Bio-based derivative of âfossilâ polymers6- New polymers from biomass7- Conclusions and perspectivesMaste
6-O-glucose palmitate synthesis with lipase: Investigation of some key parameters
International audienceFatty acid sugar esters represent an important class of non-ionic bio-based surfactants. They can be synthesized from vinyl fatty acids and sugars with enzyme as a catalyst. Herein, the influence of the solvent, the lipase and the temperature on a model reaction between vinyl palmitate and glucose via enzymatic catalysis has been investigated and the reaction conditions optimized. Full conversion into 6-O-glucose palmitate was reached in 40âh in acetonitrile starting from a reactant ratio 1:1, at only 5%-wt loading of lipase from Candida antarctica B (CALB) without the presence of molecular sieves
Synthesis of Fatty Acid-Based Polyesters and Their Blends with Poly(L-lactide) as a Way To Tailor PLLA Toughness
10.1021/sc500648gInternational audiencePolylactide (PLA) is one of the most mature biobased and biocompostable plastics currently in the market. Despite its mechanical properties comparable to the ones of some mainstream petroleum-based thermoplastics (PS, for instance), PLA inherent brittleness and heat sensitivity are issues for its full industrial development. In this study, we investigated the melt-blending of PLLA (poly-L-lactide) with fatty acid-based flexible polyesters as an efficient way to tailor PLLA toughness. To that aim, a set of aliphatic polyesters has been developed by taking benefit of the large range of biobased building blocks that can be obtained from plant oils. Melt-blending of the so-formed polyesters with PLLA resulted in improved properties that can be finely tailored by varying the structure and the properties of the plant-based polyester additives
Impact of Fatty Acid Structure on CALBâCatalyzed Esterification of Glucose
International audienceEnzymatic synthesis of fatty acid glucose esters from different fatty acyl donors were performed via enzymatic catalysis in the presence of CALB, using acetonitrile as the solvent. The acyl donor nature (fatty acid or fatty acid vinyl ester) and structure were varied. Lower reaction rates and lower conversions were obtained with fatty acids in comparison to their corresponding vinyl esters. Moreover, the acyl donor with the longest chain length gave the highest conversions. The presence of unsaturation on the acyl donor chain was also shown to be detrimental to the conversion
Synthesis and Characterization of Epoxy Thermosetting Polymers from Glycidylated Organosolv Lignin and Bisphenol A
International audienceDiglycidylether of bisphenol A and isophorone diamine (IPDA) are industrially used for polyepoxide curing. Herein, glycidylated Organosolv lignin (GOL) is cured with diglycidyl ether of bisphenol A and IPDA for intensive studies. Organosolv lignin (OL) is therefore first glycidylated with epichlorohydrin to a material with an epoxy content of 3.2 mmol gâ1 and analyzed via FTâIR, 1H and 31P NMR. Epoxy thermosets with up to 42 wt% GOL are cured in differential scanning calorimetry (DSC) crucibles, analyzing the residual reaction heat. Characterization of dog bone shaped specimens is described with regard to structural properties from scanning electron microscopy and FTâIR, thermal properties by DSC and thermogravimetric analysis, as well as mechanical properties by dynamic mechanical analysis and stress/strain measurements. A lignin content between 8% and 33% leads to higher crosslinking density, resulting in a higher glass transition, lower swelling percentage, and increased stiffness (Young's modulus) if compared to nonâGOL polymers
Organogels from trehalose difatty esters amphiphiles
International audienceSaccharide diesters have been recently shown to be excellent gelators of vegetable oils. In this paper, different fatty acid trehalose diesters were synthesized by a selective enzymatic transesterification performed only on the primary hydroxyl group of the trehalose. The resulting trehalose diesters demonstrated their ability to self-assemble in a large variety of edible vegetable oils with a minimum gelation concentration of 0.25 wt%/v. Microscopic analysis and X-ray scattering studies indicate that the gels are obtained by the self-assembly of trehalose diesters in crystalline fibers constituting the tridimensional network. The rheological study revealed that the properties of the gels depend on the kind of fatty acid grafted on the trehalose but are also influenced by the vegetable oil composition
Bio-Based Polyricinoleate and Polyhydroxystearate: Properties and Evaluation as Viscosity Modifiers for Lubricants
This paper aims to design bio-based polyester as a viscosity modifier for lubricant properties. Bio-based polyricinoleate (PRic) and its saturated homologous polyhydroxystearate (PHS) have been synthesized from fatty acid methyl esters. The polycondensation performed in bulk in a one-step reaction without any purification leads to two series of polyesters within a large range of molecular weights, with Mw between 3 and 130 kg·molâ1. Their thermal properties were investigated. Good thermal stability was observed with degradation temperatures above 300 °C. As expected, PRic appeared to be amorphous with a particularly low glass-transition temperature, while PHS is semicrystalline. A rheological study determined that polyricinoleate entangled when its molecular weight was above 25 kg·molâ1. These two bio-based and biodegradable polymers were then evaluated as viscosity modifiers in both organic and mineral oils. PHS with high molecular weights appeared to be an excellent thickener as well as a good viscosity index improver with a viscosity index (VI) increase above +50 in organic lubricant oil and +64 in mineral oil
Ester-Containing Imidazolium-Type Ionic Liquid Crystals Derived from Bio-based Fatty Alcohols
The need to take into account the life cycle of ionic liquids (ILs), from the sourcing of the raw materials involved in their synthesis to their disposal and degradation, has become paramount in the design of new IL-type molecular structures. In the case of 1-alkyl-3-methylimidazolium salts, one of the prominent IL families, there is an increasing demand for synthetic methods involving (i) substitution of the petro-based alkyl derivatives by readily available bio-sourced surrogates and (ii) functionalization of the alkyl tail with heterofunctional groups enabling the (bio)degradation of ILs after use. Herein, a straightforward and industrially viable synthesis of lipidic imidazolium salts is reported, starting from different bio-sourced fatty alcohols, including oleic, stearyl, and lauryl alcohols. This procedure is based on the acrylation of fatty alcohols, followed by the aza-Michael addition of the imidazole group onto the acrylate moiety. Subsequent quaternization, using either methyl iodide or methyl tosylate, provides a library of 1-alkylpropionate-3-methylimidazolium salts with various alkyl chain lengths (C18, C12, and C11) and incorporating different types of counteranions (iodide, tosylate, and tetrafluoroborate). These ester-containing analogues of classical 1-alkyl-3-methylimidazolium salts are all ILs, that is, with a melting point below 100 °C. In addition, most of them exhibit a liquid-crystal behavior and can be referred to as IL crystals (ILCs). The thermal stability, as well as the phase transitions of these ILs, has been investigated by thermogravimetric analysis, as well as differential scanning calorimetry, respectively, while the molecular structure into the crystalline phase and the mesophase is studied by X-ray scattering. Interestingly, ILCs featuring unsaturated alkyl tails exhibit a low melting point, close to room temperature, and the presence of the ester function is shown to provide an enhanced stabilization of the mesophase
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