Search

International audience; The aminolysis of five-membered cyclic carbonates, which results in polyhydroxyurethanes (PHUs), is one of the most promising synthetic pathways to achieve isocyanate-free polyurethanes (NIPUs), one of the main industrial challenges over the coming years. This study highlights the higher reactivity of β-hydroxylamines toward cyclic carbonates compared to classical alkylamines through the determination of their reaction rate constants. The key role of the β-OH substituent in the aminolysis was revealed by DFT investigation. Polyfunctional alkylamine and β-hydroxyamine were then used for the synthesis of fully biobased PHU thermosets. The higher reactivity of β-hydroxylamines was confirmed by the gelation time gap between the two formulations studied. After curing, the thermal and thermo-mechanical properties of the thermosets were compared.

International audience; We report the synthesis and ring-opening polymerization of new formaldehyde-free benzoxazines. The polybenzoxazines obtained displayed high thermal stability and high char yields. Data from the literature combined with our analyses by differential scanning calorimetry and thermogravimetric analyses gave deeper understanding about the use of aromatic aldehydes instead of formaldehyde for the generation of polybenzoxazines. Using pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) at different temperatures, we provided qualitative data to propose some polymerization and degradation mechanisms associated with these new structures. A dialdehyde was also used for the first time in order to obtain difunctional monomers, instead of using diamines or bisphenols. Interestingly, we demonstrated that formaldehyde, which is a CMR (carcinogenic, mutagenic, and/or reprotoxic) substance, could be avoided for the synthesis of polybenzoxazines without any loss of thermal performance. Finally, some interesting structure–properties relationships are herein discussed. In particular, the use of benzyl amines, rather than aromatic amines, was found to significantly increase the char yields.

Biobased monomers and green processes are key to producing sustainable materials. Cardanol, an aromatic compound obtained from cashew nut shells, may be conveniently functionalized, e.g., with epoxy or (meth)acrylate groups, to replace petroleum-based monomers. Photoinduced polymerization is recognized as a sustainable process, less energy intensive than thermal curing; however, cardanol-based UV-cured polymers have relatively low thermomechanical properties, making them mostly suitable as reactive diluents or in non-structural applications such as coatings. It is therefore convenient to combine them with biobased reinforcements, such as microfibrillated cellulose (MFC), to obtain composites with good mechanical properties. In this work a cardanol-based methacrylate monomer was photopolymerized in the presence of MFC to yield self-standing, flexible, and relatively transparent films with high thermal stability. The polymerization process was completed within few minutes even in the presence of filler, and the cellulosic filler was not affected by the photopolymerization process.

BioPolymers could be either natural polymers (polymer naturally occurring in Nature, such as cellulose or starch…), or biobased polymers that are artificially synthesized from natural resources [...]

International audience; Chitooligosaccharides with degree of polymerization from 5 to 15 have been modified with different lipophilic chains, from fatty epoxide to fatty acids. Their interfacial properties such as critical micellar concentrations, interfacial rheology and interfacial tension were studied to establish structure-properties relationships. Their ability to self-assemble as well as their micellar shape were assessed by light scattering (dynamic and static) and transmission electron microscopic analyses. Finally, their emulsion stabilities and rheological properties were evaluated with Turbiscan and allow the conclusion that 1% (w/w) DP10 oligomers modified with Tall oil fatty acid was able to stabilize oil in water emulsions (60/40 w/w) for at least 55 days.

International audience; Biobased materials, derived from biomass building blocks, are essential in the pursuit of sustainable materials. Eugenol, a natural phenol obtained from clove oil, but also from lignin depolymerization, possesses a chemical structure that allows its easy modification to obtain a broad and versatile platform of biobased monomers. In this review, an overview of the variety of reactions that have been executed on the allylic double bond, phenol hydroxyl group, aromatic ring and methoxy group is given, focusing our attention on those to obtain monomers suitable for different polymerization reactions. Furthermore, possible applications and perspectives on the eugenol-derived materials are provided.

International audience; The anionic alternating ring-opening copolymerizations of three bio-based aromatic monomers, eugenol glycidyl ether (EGE), dihydroeugenol glycidyl ether (DEGE) and vanilin glycidyl ether (VGE), were carried out with renewable N-acetyl homocysteine thiolactone (NHTL) using benzyl alcohol and 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP) as initiating system. This polymerization is a rare example of eugenol-based monomers used to synthesize linear polyesters. Alternating poly(ester-alt-thioether)s are obtained with number-average molar masses M n ranging from 1.1 to 10.8 kg mol-1 and dispersities as low as 1.20. The copolymer structures were carefully characterized by 1 H, 13 C, COSY, HSQC, 1 H-15 N NMR. It was found that the alternate copolymers were obtained selectively under different monomer feed ratios. In addition, the use of EGE and VGE monomers allows the preparation of multi-functional poly(ester-alt-thioether) respectively bearing allyl or aldehyde groups in each repeating unit. The copolymers display only clear glass transition temperatures higher than ambient temperature. This alternating copolymerization method offers a new chemical pathway for the valorization of bio-based aromatic compounds and expand the scope of renewable polyesters.

International audience; Chitooligosaccharides (COS) differ from chitosan by their molar mass: those of COS are defined to be lower than 20 kg mol−1. Their functionalization is widely described in the literature and leads to the introduction of new properties that broaden their application fields. Like chitosan, COS modification sites are mainly primary amine and hydroxyl groups. Among their chemical modification, one can find amidation or esterification, epoxy-amine/hydroxyl coupling, Schiff base formation, and Michael addition. When depolymerized through nitrous deamination, COS bear an aldehyde at the chain end that can open the way to other chemical reactions and lead to the synthesis of new interesting amphiphilic structures. This article details the recent developments in COS functionalization, primarily focusing on amine and hydroxyl groups and aldehyde-chain end reactions, as well as paying considerable attention to other types of modification. We also describe and compare the different functionalization protocols found in the literature while highlighting potential mistakes made in the chemical structures accompanied with suggestions. Such chemical modification can lead to new materials that are generally nontoxic, biobased, biodegradable, and usable in various applications.

International audience; Along with characterization of vinyl monomers from high oleic soybean oil (HOSBM) and cardanol (CBM) in free radical (co)polymerization, a series of stable latexes based on various ratios of these fully renewable plant-based monomer mixtures have been synthesized using a miniemulsion process. The combination of aliphatic fatty acid fragments of HOSBM with aromatic CBM structure led to the formation of durable latexes from fully renewable feeds as well as the ability of the resulting cross-linked latex films to balance thermomechanical properties. Biobased latexes were synthesized from 10 to 75 wt % of CBM and 25–90 wt % of HOSBM in the feed, characterized, and tested in films and coatings performances. The synergistic effects of both the constituents in the films and coatings were observed. The incorporation of cardanol-based fragments enhances the Young’s modulus of the films, whereas the plant oil-based units contribute to softer and more flexible films. Even small (10 wt %) fractions of CBM can provide noticeable strength to the soft latex polymer material based entirely on HOSBM. All cross-linked latex films in this study exhibit decent properties and performance in terms of pendulum and pencil hardness, water and solvent resistance, as well as adhesion to the steel substrate. To the best of our knowledge, latexes from fully renewable plant-based monomer mixtures have not been reported before in literature.

A recently revisited biobased styrenic monomer, acetyl-protected 4-vinylguaiacol (AC4VG), was used for the synthesis of partially biobased, functional core–shell polymers. P(S-co-BA)@PAC4VG and PBA@PAC4VG latex particles with a PAC4VG shell were prepared using a two-step seeded radical emulsion polymerization process. The P(S-co-BA) and PBA seed particles were synthesized first, and the AC4VG monomer was subsequently added as a pre-emulsion over time. The aqueous emulsion polymerizations were carried out at 10 wt% solids at 80 °C using ammonium persulfate as a radical initiator and sodium dodecyl sulfate as a surfactant. These polymerizations resulted in colloidally stable latexes with high monomer conversions (>95%). The resulting particles were 80–90 nm in diameter (intensity-average) and TEM observations revealed core–shell and partially encapsulated particle morphologies. Up to 70% of the acetoxy groups of PAC4VG in the P(S-co-BA)@PAC4VG latex were deprotected under mild basic conditions over 18 hours to produce core–shell polymers decorated with phenolic functions on their surface. This deprotection procedure did not adversely affect the particle size or colloidal stability of the latex. Finally, partially biobased phenolic networks (phenolic resins) were produced from these functional core–shell particles by crosslinking with glyoxal, a naturally-sourced dialdehyde.

International audience; 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 (MAEOSC12), 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 M feed ratio and were fully characterized through 1H 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 improvement of thickening power with temperature in OTO was further optimized by increasing the copolymer molecular weight, dispersity, concentration, pendant aliphatic chain length or by adding an additional aliphatic chain in the copolymer backbone. Moreover, copolymer additions in OTO did not disturb the initial Newtonian behavior of OTO at −30 °C which corresponds to the lube oil pour point.

Fulfilling the Paris Climate Agreement requires reducing rapidly the new emissions of greenhouse gases (GHGs) to reach net zero by 2050. As some anthropogenic emissions cannot be zero, to compensate them it will be necessary to remove GHGs from the atmosphere. Among possible methods, the Iron Salt Aerosol (ISA) offers new possibilities, including removal of methane and several other GHGs, as well as carbon dioxide. Several studies suggest that anthropogenic emissions of iron participate in the current primary productivity. As plans to decarbonize the world economy might also have inadvertent warming effects due to the reduction of iron emissions from fossil fuels burning, iron additions might help address this issue. ISA is different from the method known as Ocean Iron Fertilization and the differences are explained. ISA mimic natural processes and the dust which probably participated in the cooling during the ice-ages over the past million years. Still larger laboratory trials, safety and environmental impact studies and global chemical computer modeling are necessary before ISA would be ready to be trialed. Desk and laboratory studies indicate low cost, easy deployment and efficacy, all of which can be validated by future small scale field trials, a step needed before, if successful, a possible implementation at a climate-relevant scale.

International audience; Four different films were prepared from chitosan modified with furfuryl glycidyl ether (FG) by Diels Alder reaction with different maleimide-based cross linker. At first, a preliminary study led to structural identification and better understanding of the reaction. For the first time, Diels-Alder and retro Diels-Alder reactions were evidenced by NMR spectroscopy and DSC on chitosan based systems. Then, chitosan of 30,000 g/mol and 150,000 g/mol were modified by FG with 20% substitution degree (DS). The resulting products were then cross-linked with bis and trimaleimide cross-linkers to produce films possessing interesting mechanical properties. For the first time for chitosan-based films, DMA measurement highlighted retro Diels-Alder between 110 and 130°C. Film also showed interesting hydrophobicity and fat absorption. They also exhibited resistance in acidic media whereas crude chitosan films were destroyed.

International audience; Hydrophobically modified chitooligosaccharides (COSs) were tested for suitability as an emulsifier in cationic bituminous emulsions. COSs with polymerization degrees (DPs) of 5, 10, 15, and 20 were obtained by nitrous acid deamination. A complete study on depolymerization and precise product and side product characterization was undergone. Chemical modification of COSs was performed to achieve amphiphilic structures using three fatty epoxides with a growing chain length butyl (C4), octadecyl (C9), and hexadecyl glycidyl ether (C16)). The grafting efficiency according to reaction conditions was established. Different substitution degrees (DSs) were obtained by modulating the ratio of fatty epoxy to NH2. It was shown that after a certain DS, the oligomers thus formed were not water-soluble anymore. At the end, cardanol glycidyl ether was grafted on DP 5, 10, and 15 COSs, cardanol being a biobased compound extracted from cashew nut shell; this reaction led to a potentially fully biobased structure. Water-soluble candidates with a higher DS were used as surfactants to emulsify motor oil as a simulation of bitumen. Cardanol–chitosan-based surfactants led to direct oil-in-water emulsion (60/40 w/w) composed of particles of 15 μm average size that were stable at least for 24 h.

International audience; A series of biobased conjugated dienes with exo-methylene and a 6-membered ring was prepared from naturally abundant terpenoids bearing an ,-unsaturated carbonyl group, such as verbenone, piperitone, or carvone, and cationically polymerized to form novel biobased cycloolefin polymers with characteristic structures originating from natural products. The obtained exo-methylene-conjugated dienes showed high cationic polymerizability comparable to that of vinyl ethers despite the absence of electron-donating heteroatoms. The polymerization proceeded via regioselective 1,4-conjugated addition by initiating systems effective for living cationic polymerization of vinyl ethers, resulting in well-defined polymers with controlled molecular weights and substituted cyclohexenyl rings in the main chain. These polymers showed high glass transition temperatures (Tg) ranging from 110 to 160 °C depending on the substituents. The hydrogenation of the mainchain cyclohexenyl ring resulted in novel biobased cycloolefin polymers with good thermal stability. The reactivity of the exo-methylene-conjugated diene monomers was evaluated by living cationic copolymerizations with a series of vinyl ethers with different reactivities, i.e., isopropyl, isobutyl, and 2-chloroethyl vinyl ether. In particular, the dienes possessing a methyl group at the 4-position, which can generate a conjugated tertiary cation, were more reactive than a representative vinyl ether with an isobutyl substituent. The sequence distribution of the copolymers varied from statistically random to tapered block structures depending on the monomer reactivities. Block copolymerizations of the dienes and vinyl ethers using the same initiating system for sequential monomer addition resulted in well-defined block copolymers bearing high (> 100 °C) and low (~ 0 °C) Tg segments, of which microphase separation was confirmed by atomic force microscopy of the thin film.

In recent years, polymer chemistry has experienced an intensive development of a new field regarding the synthesis of aliphatic and aromatic biobased monomers obtained from renewable plant sources. A one-step process for the synthesis of new vinyl monomers by the reaction of direct transesterification of plant oil triglycerides with N-(hydroxyethyl)acrylamide has been recently invented to yield plant oil-based monomers (POBMs). The features of the POBM chemical structure, containing both a polar (hydrophilic) fragment capable of electrostatic interactions, and hydrophobic acyl fatty acid moieties (C15-C17) capable of van der Waals interactions, ensures the participation of the POBMs fragments of polymers in intermolecular interactions before and during polymerization. The use of the POBMs with different unsaturations in copolymerization reactions with conventional vinyl monomers allows for obtaining copolymers with enhanced hydrophobicity, provides a mechanism of internal plasticization and control of crosslinking degree. Synthesized latexes and latex polymers are promising candidates for the formation of hydrophobic polymer coatings with controlled physical and mechanical properties through the targeted control of the content of different POBM units with different degrees of unsaturation in the latex polymers.

International audience; The increasing concern about the environmental impact of physical blowing agents (PBAs) favours the use of chemical blowing agents (CBAs) to replace controversial PBAs. Blowing agents are key compounds in order to obtain polymer foams. Indeed, blowing agents are crucial additives that release gas needed to blow polymer foams. CBA compounds have been widely studied in recent decades, and today if new CBA are studied, one of the challenges remains to adapt the use of CBA to new polymers or new formulations. Only a handful of books present different CBAs commercially available but in these documents, the presentation of CBAs is not enough complete to understand potential or limits. Thus, our work is focused on the most common, both inorganic and organic chemical blowing agents and highlights the specifications of these CBAs, with their advantages and drawbacks, and finally presents promising perspectives.

International audience; Hydrophobically modified ethoxylated urethanes (HEURs) are associative polymers that, compare to others, are far less sensitive to solution parameters, especially pH and ionic strength. Therefore, they are widely used as rheology modifiers in many different waterborne systems such as inks, coatings, emulsions, etc. In solutions, HEURs form transient networks through molecular associations between their hydrophobic groups. The transient network formation and its characteristics are responsible for the rheological properties and depend on the HEUR chains architecture. Many parameters such as molecular weight, size and nature of hydrophobic groups, polymer concentration, etc must be controlled to tune the several physicochemical properties of HEUR solutions. This article aims to give an overview of the HEUR studies reported in the literature in order to highlight the structure/rheological properties relationship. The article also draws attention to new trends in HEURs with innovative architectures and stimuli-responsive properties.

Permanently crosslinked polymer networks, such as fully cured thermosets derived from fossil-based epoxies, cannot be reuse after damage and/or recycled since they cannot be reprocessed by heating or solubilization as non-crosslinked thermoplastics. As a result, they are not really sustainable materials, generating non-renewable resources consumption, CO2 emissions and plastic pollution. Herein we employed a strategy to tackle the lack of sustainability in conventional thermosets by the development of a promising partially biobased epoxy for numerous applications, integrating a covalent adaptable network using associative dynamic chemistry and catalyst free mechanism. This strategy is based in two sustainable approaches. First, vegetal biomass has been used as a renewable resource for the synthesis of epoxy systems from epoxidized eugenol oil. Then, the crosslinking reaction with a diamine integrating disulfide bonds to attain a thermally induced reorganizable eugenol-derived epoxy network in a dynamic way by disulfide metathesis reaction. The viscoelastic behavior characterization of eugenol-derived epoxy network displays a fast macroscopic flow with a stress relaxation time of 37 s at 230 °C, suggesting an interesting melt-reprocessability of this network at high temperatures in short times. Moreover, this strategy has a strong potential for the progress of sustainable plastic applications as yield a synthetic procedure to develop stiff thermosets (storage modulus of around 1 GPa at glassy state) with high renewable carbon contents (around 70 wt%), enhanced thermal properties (Tg of around 190 °C) and additional properties such as promising reshaping, repairing and recycling capability.

International audience; Biobased monomers derived from eugenol were copolymerized by emulsion polymerization to produce latexes for adhesive applications. Stable latexes containing ethoxy dihydroeugenyl methacrylate and ethoxy eugenyl methacrylate with high total solids content of 50 wt% were obtained and characterized. Latexes synthesis was carried out using a semi-batch process and latexes with particle diameters in the range of 159-178 nm were successfully obtained. Glass transition temperature values of the resulting polymers ranged between -32 and -28°C. Furthermore, tack and peel measurements confirmed the possibility to use these latexes in adhesive applications.

International audience; There was a crucial need to eliminate formaldehyde (F) from high-performance thermoset formulations. The catalyzed reaction of innovative phenol (P)-terephthalaldehyde (TPA) resoles (basic conditions) was studied. For aerospace applications, alkali- or alkaline-earth-based catalysts should be avoided. To address this issue, we successfully employed DBU to catalyze the resole formation (with NaOH as reference system). The pre-polymerization (addition of phenol onto the first aldehyde of TPA) was performed in solution under mild conditions and followed by NMR and IR. Sodium hydroxide catalyzed rather effectively the reaction of ortho phenolic positions (1:1 ortho:para) whereas DBU catalyzed more para positions (ca. 1:2 ortho:para), because of the absence of chelating behavior of Na+. Based on non-isothermal DSC of the thermosets curing, we proposed a two-step mechanism pathway, directly arising from the multiple reactions occurring with TPA. The first reaction was assigned to the condensation reaction as its reactivity was enhanced by the unreacted aldehyde in para position (invariant aldehyde content measured in IR and weight loss recorded in TGA). The second was assigned to the addition of the phenol onto the second aldehyde (decrease of aldehyde and no weight loss). An in-depth non-isothermal thermo-kinetics study was efficient to compare both NaOH and DBU catalyzed reactions (isoconversional computational method of Vyazovkin). The isoconversional analysis allowed to discriminate the activation energies of the addition and condensation reactions (NaOH: 78 and 72 kJ·mol−1; DBU: 63 and 49 kJ·mol−1, respectively). Finally, TGA results showed that these new resoles presented increased thermal performances as compared to a commercial PF (Td10% ≥ 470 °C and char yield ≥ 64 wt%).

International audience; A new efficient type I photoinitiator derived from vanillin was synthesized to initiate, according to a green photoinduced process, the free-radical polymerization (FRP) of acrylate monomers in a reduced time and under air. Interestingly, this unprecedented photoinitiator lead to high acrylate conversions even under air, with a higher efficiency than some reference photoinitiating systems commonly used in FRP.

International audience; 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.

International audience; A green strategy for the synthesis of nonisocyanate polyester-urethanes (NIPHEUs) was developed. These NIPHEUs were synthesized by step growth polymerization combining sugar-derived dimethyl-2,5-furan dicarboxylate (DMFD) with polyhydroxylurethanes (PHUs) adducts bearing four hydroxyl groups. The later hydroxyl urethane tetraols (HU-tetraols) building blocks were prepared by aminolysis of glycerol carbonate with two different aliphatic diamines having different chain lengths, 8 and 12 carbons. Qualitative and quantitative NMR analyses of the HU-tetraols showed the presence of primary and secondary hydroxyl moieties at different ratios. Hence, in the polycondensation stage, the stoichiometry of the diester was varied from 1 to 6 equiv in order to tailor the structural features of the prepared NIPHEUs. The success of the chain extension through polycondensation was confirmed by FTIR and NMR analyses. Thermal analyses of these new polymers demonstrated satisfactory thermal stability, with onset degradation temperatures ranging from 170 to 220 °C where the main first degradation stage occurs. Their melting temperatures ranged between 93 and 110 °C and seem to be driven by the thermal behavior of HU-tetraol monomers. Surprisingly, preliminary results from thermal analyses revealed the occurrence of a striking thermal change in the NIPHEUs upon repetitive heating cycles. This behavior may be related to a thermal-induced bond exchange probably driven by transcarbamoylation reaction. Such interesting vitrimer-like behavior for this new type of NIPHEUs would be unique and should be confirmed by a deeper study before leading to a new range of functional green materials.

International audience; Biobased monomers have been used to replace their petroleum counterparts in the synthesis of polymers that are aimed at different applications. However, environmentally friendly polymerization processes are also essential to guarantee greener materials. Thus, photoinduced polymerization, which is low-energy consuming and solvent-free, rises as a suitable option. In this work, eugenol-, isoeugenol-, and dihydroeugenol-derived methacrylates are employed in radical photopolymerization to produce biobased polymers. The polymerization is monitored in the absence and presence of a photoinitiator and under air or protected from air, using Real-Time Fourier Transform Infrared Spectroscopy. The polymerization rate of the methacrylate double bonds was affected by the presence and reactivity of the allyl and propenyl groups in the eugenol-and isoeugenol-derived methacrylates, respectively. These groups are involved in radical addition, degradative chain transfer, and termination reactions, yielding crosslinked polymers. The materials, in the form of films, are characterized by differential scanning calorimetry, thermogravimetric, and contact angle analyses.

In this paper, novel epoxy prepolymers from oleic acid-based monomers were cross-linked to prepare thermosets for coating application. For this purpose, methacrylate moiety was firstly added to oleic acid via Steglich esterification prior to conventional radical polymerization. The resulting oleic acid-based polymer was obtained with a number molecular weight 40,000 g/mol (DP = 110). Then the internal unsaturations of this polymer were epoxidized at different epoxy contents to provide cross-linkable functionalities. Based on a study of the internal epoxy reactivity of a model compound with different nucleophiles, the synthesized oleic-based polymers with epoxy functions hanging off the main chain were successfully cross-linked with succinic anhydride. Dynamic mechanical and thermal analyses, as well as swelling index properties have been studied for all the resulting thermosets. Additionally, the properties of coatings on steel substrates were studied to determine coating hardness, and adhesion. The results of this work provide evidence of the potential of these materials as bio-based coatings and adhesives.

In the scope of fully bio-based materials development, access to bio-based aromatic amine monomers is one of the main industrial challenges over the coming years. In this paper, new bio-based amine monomers derived from vanillin were prepared by the direct amination of an epoxy monomer with aqueous ammonia. These synthesized amines exhibited high reactivity due to the presence of secondary OH groups. Then these amines were added to epoxies to form thermosets by a cross-linking reaction. After curing, the thermal and mechanical behaviors of the synthesized networks were determined and compared to that of a petroleum-based reference system with DGEBA as an epoxy.

We present for the first time the aqueous emulsion radical polymerization of cardanol derived methacrylic monomer (CAMA) in order to pave the way for the replacement of styrene. This monomer was synthesized in two-step routes by epoxidation of cardanol prior to methacrylation. Polymerization of CAMA was studied both in toluene solution and in aqueous emulsion. Radical aqueous emulsion homo- and co-polymerization of CAMA with methyl methacrylate (MMA) were performed with sodium dodecyl sulfate as surfactant. Stable latexes were obtained with particle size between 25 and 75 nm. CAMA and MMA conversions were monitored versus time. Influence of radical initiator was studied on gel content, showing transfer to monomer in the case of persulfate as initiator. Glass transition temperature of homoPoly(CAMA) was determined and is suitable for coating application. Photo-crosslinking was performed by thiol-ene chemistry and allowed yielding cross-linked biobased aromatic coatings.

Power stations, ships and air traffic are among the most potent greenhouse gas emitters and are primarily responsible for global warming. Iron salt aerosols (ISAs), composed partly of iron and chloride, exert a cooling effect on climate in several ways. This article aims firstly to examine all direct and indirect natural climate cooling mechanisms driven by ISA tropospheric aerosol particles, showing their cooperation and interaction within the different environmental compartments. Secondly, it looks at a proposal to enhance the cooling effects of ISA in order to reach the optimistic target of the Paris climate agreement to limit the global temperature increase between 1.5 and 2 °C. Mineral dust played an important role during the glacial periods; by using mineral dust as a natural analogue tool and by mimicking the same method used in nature, the proposed ISA method might be able to reduce and stop climate warming. The first estimations made in this article show that by doubling the current natural iron emissions by ISA into the troposphere, i.e., by about 0.3 Tg Fe yr−1, artificial ISA would enable the prevention or even reversal of global warming. The ISA method proposed integrates technical and economically feasible tools.

The development of high-performance materials from renewable resources is of paramount importance in a sustainable development context. In this paper, a novel bio-based epoxy monomer derived from eugenol was prepared by treating phosphorus oxychloride with eugenol, followed by epoxidation with m-CPBA. The structure of the epoxy monomer was elucidated by NMR. After curing, the thermal and mechanical properties of the obtained thermoset were evaluated by DSC, TGA and DMA and compared with those of the commercial petroleum-based epoxy monomer DGEBA.

Thermo-reversible networks were obtained for the first time from tannins, an aromatic biobased polyphenol, by reacting furan-bearing tannins and telechelic oligomers with maleimide end groups, using the Diels−Alder (DA) reaction. Condensed tannins from mimosa (Acacia mearnsii) were functionalized with furfuryl glycidyl ether and thoroughly characterized by 1H, 31P NMR, and FTIR spectroscopy. The accessibility of the grafted furan groups was confirmed by a model reaction with N-methylmaleimide. Different cross-linked networks were then obtained by DA reaction with three PPO and PPO-b-PEO-b-PPO oligomers and evidenced by FTIR spectroscopy. The thermal properties of the obtained networks were evaluated with differential scanning calorimetry (DSC) and thermogravimetric analysis. Then, the reversibility of the cross-linking was shown by a quick return to the liquid state upon heating at 120 °C. The retro Diels−Alder reaction was studied by size exclusion chromatography and DSC.

Most of the current amines are issued from petrochemical resources and only a few of them are derived from biomass. Hence, there are increasing expectations for bio-based amines, particularly for aromatic ones. We have designed and synthesized new bio-based amines containing aromatic moieties from cardanol, an aromatic non-edible co-product from agri-food industry of cashew nut. We used green amination reaction of epoxy monomers with ammonia under microwave irradiations, from two commercial epoxidized cardanol monomers with different epoxy functions: NC-514 and GX-2551 (Cashew, nutshell liq., polymer with epichlorohydrin). We studied the efficiency of our amination route onto both glycidyl and epoxy functions at the middle of the chain and the reactivity of synthesized amines toward ring opening of epoxy function. The synthesized bio-based amines were further evaluated as curing agents for epoxy resins. The thermo-mechanical properties of final bio-based thermosets synthesized therefrom are almost similar (Tg = 51 °C, Td5% = 332 °C and Tα = 64 °C for T-NC thermoset, Tg = 58 °C, Td5% = 340 °C and Tα = 78 °C for T-GX thermoset). Moreover, another aim of this study was to reduce the viscosity of hardeners compared to DHAVA hardener (400 000 mPa s at 50 °C), which was synthesized in previous work. Lower viscosities were observed in the case of cardanol-based hardener (362 000 and 33 000 mPa s at 50 °C for respectively NC-A and GX-A hardener).

International audience; A fully bio-sourced and biodegradable composite material has been developed based on polyhydroxybutyrate and hemp fibres (20 wt% content). Improvements of the final performances of composite materials were shown to depend highly on the filler dispersion state and on the polar filler/apolar matrix interface. Those two parameters were tuned by playing around with the processing conditions (screw profile and speed) and the formulation (possible recourse to a green compatibiliser). The so-prepared biocomposites exhibited homogeneous structures, a controlled matrix–fibre interface and suitable thermal properties. Even if the materials also suffered some matrix degradation from identified sources, their mechanical properties were maintained and their water vapour sensitivity could be tuned by the processing conditions and formulation. The strong nucleating effect provided by the fibres has been highlighted, and a clear fibre–matrix load transfer confirmed the effectiveness of the prepared compatibiliser. Concerning the end of life, the high biodegradability of the fully bio-based composites in compost was also confirmed.

International audience

A series of bio-based epoxidized plasticizers (CExEp) for soft PVC was synthesized from cardanol and various fatty acids by esterification and epoxidation of the fatty and cardanol unsaturations. The plasticizing properties of these additives for PVC films were proved considering thermal and mechanical data. They seem to be a potential bio-based alternative plasticizer to diisononyl phthalate (DINP), one of the most widespread phthalate plasticizers, with less rigid and stable films. The synergy between epoxy groups, cardanol ring and fatty chains to elaborate efficient primary plasticizers was demonstrated. Moreover, the eco-toxicity using daphnies, algae, and plants as model organisms and endocrinal disruptor tests (YES/YAS) were realized. Our results revealed that the fatty cardanol plasticizer causes a global decrease in toxicity compared to DINP and no harm for environment and human health were detected without endocrine perturbation effect. These positive results of toxicology allow to consider these cardanol plasticizers in industrial applications as alternative to DINP.

International audience; Graphical Abstract Abstract Chemistry in general, but polymer chemistry in particular has to face the major challenge of finding solutions to ensure a sustainable and environmental-benign development of industry to answer consumer needs. Aromatics are very important chemical groups for polymer science for the synthesis of lots of thermostable or thermosetting polymers. However, most petrobased aromatic monomers (such as phenol) are toxic. Finding less toxic and sustainable aromatics is not easy because natural phenols have various functionalities in nature. In consequence aromatic-containing building blocks must be synthesized. The present review gives an overview of the different synthetic methods to prepare such aromatic building blocks by various coupling methods. It then focusses on the synthesis of CC bonds, on reductive coupling of natural aldehydes, on the carbonyl-aromatic coupling and on other various routes to prepare monomers. Indeed, owing to the rich reactivity and properties of aromatics, such functional monomers will undoubtedly lead to the development of high-added value polymers. This review also gives a brief overview of such potential applications.

The increasing price of barrels of oil, global warming, and other environmental problems favor the use of renewable resources to replace the petroleum-based polymers used in various applications. Recently, fatty acids (FAs) and their derivatives have appeared among the most promising candidates to afford novel and innovative bio-based (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 a few works have been devoted to radical polymerization due to the low reactivity of FAs through radical process. Thus, the aim of this Review is to give an overview of (i) the most common synthetic pathways reported in the literature to provide suitable monomers from FAs and their derivatives for radical polymerization, (ii) the available radical processes to afford FA-based (co)polymers, and (iii) the different applications in which FA-based (co)polymers have been used since the past few years.

This review highlights the design and synthesis of biobased monomers from renewable resources for the preparation of latexes in aqueous dispersed media. Biobased polymers have been widely studied and are still a hot topic as environmental concerns and regulations require the use of green chemistry principles as guidelines for the synthesis of new polymer materials. Consideration should equally be given to green polymerization processes such as industrially relevant aqueous emulsion and suspension polymerizations. However, the synthesis and polymerization of biobased monomers through polymerization in aqueous dispersed media have not been sufficiently explored. Hence, constraints and opportunities arising from previous research work in this area will be presented focusing on aqueous (mini)emulsion and suspension polymerizations.

International audience; Syntheses of novel biobased PolyHydroxyUrethane (PHU) have been performed from Jojoba and castor oil. Cyclic carbonate monomers with various functionality were synthesized from both jojoba and castor oils. Pendant cyclic carbonate groups were obtained by a two-step reaction: thiol-ene coupling with thioglycolic acid followed by esterification with glycerin carbonate. These novel cyclic carbonate monomers exhibited higher reactivity than previous intra-chain plant oil-based cyclic carbonates. Di-functional jojoba oil-based cyclic carbonate was synthesized for the first time. PHUs were obtained by aminolysis of plant oil-based cyclic carbonates with various aliphatic and aromatic diamines. Structured linear and cross-linked PHUs were obtained with Tg ranging from −45 to 20 °C. The different PHU materials were characterized by SEC, FTIR, DSC, ATG and DMA measurements. These results showed the potentiality of this environmentally friendly approach to prepare plant oils-based PHU materials with interesting performances.

International audience; In this study, various novel cyclic carbonate-siloxane monomers were synthesized by hydrosilylation and CO2 carbonation of allyl glycidyl ether and epoxy-eugenol functions. Different structures were obtained from cyclic siloxane (D4) or linear PMHS-PDMS polymers with dangling cyclic carbonate functions. This hybrid route gives access to highly functional and low viscous cyclic carbonate monomers. Cyclic siloxane-carbonate monomers were reacted with 1,5-diamino-2-methylpentane (DYTEK-A) and 1,3-cyclohexanebis(methylamine) (CBMA) to afford polyhydroxyurethane (PHUs) thermosets as non-isocyanate polyurethanes (NIPUs) with high conversions and good reactivity. PHU thermosets were characterized to compare the thermal and mechanical properties of those different structures. The impact of the functionality was highlighted with different functional oligomers playing on cross-linking density of materials. D4 structure led to short and functional star shape monomers and afforded polymers with the highest mechanical properties. Eugenol, with an aromatic moiety, increased the stiffness and the thermal stability of PHU thermosets. Such hybrid PHU-siloxanes polymers combined flexibility of siloxanes with high mechanical performances of urethane groups.

International audience; With a global production of around 18 million tons (6th among all polymers) and a wide range of applications such as rigid and soft foams, elastomers, coatings and adhesives, Polyurethanes (PUs) are one of the major polymer family. Nevertheless, they present important environmental and health issues. Recently, new and safer Polyurethanes, called NonIsocyanate Polyurethanes (NIPUs), have become a promising alternative to replace conventional PUs. Sustainable routes towards NIPUs will be discussed in this review from a green chemistry perspective. This paper will mainly focus on the reaction between biobased carbonates and amines which offers an interesting pathway leading to renewable Polyhydroxyurethanes (PHUs). The overview of the different routes for PHUs synthesis will draw attention to the green synthesis of cyclic carbonate (CC) compound and the aminolysis reaction. A state-of-the-art of different biobased building-blocks for PHUs synthesis will focus on CC compounds. Three classes of compounds will be defined according to the feedstock with (i) vegetable fats and oils, (ii) starch and sugars resources, and (iii) wood derivatives. Finally, biobased PHUs properties will be discussed.

International audience; Five chitosans with different degrees of N-acetylation (DAs), molar masses, and origins were depolymerized by nitrous acid treatment in acidic media, leading to water-soluble 2,5-anhydro-d-mannose chain end oligomers with DPn < 20. The kinetics of the reaction was studied, and the best work conditions were found to be 3 h reaction at 50 °C. It was shown that the DPn of oligomers only depends on the quantity of NaNO2 involved. Molar masses or DAs do not have an impact on the depolymerization process when targeting oligomers with less than 20 units. This depolymerization process also leads to free 2,5-anhydromannofuranose (AMF) that might react with the free amines of obtained oligomers to form imines. This reaction is pH-dependent and in acidic condition leads to the formation of 5-hydromethyl-2-furfural (HMF). At the end, the oligomers were purified by dialysis to get rid of most of the free AMF (

International audience; This paper proposes more sustainable alternatives for the synthesis of high thermal performances phenolic networks. Terephthalaldehyde (TPA), a nontoxic aromatic dialdehyde, was selected to replace formaldehyde. Phenol was, in turns, replaced with biobased and nontoxic phenolic building blocks: resorcinol as a model for tannins, guaiacol which is easily accessible from lignin, and tyrosol from olive oil mill wastewaters. The prepolymerization was performed under mild conditions (ethanol, T ≤ 100 °C). The liquid prepolymers were characterized by NMR, IR, MALDI-ToF, and rheology. The curing behavior of these formulations was assessed by DSC and IR spectroscopy. An advanced isoconversional analysis of the DSC data allowed for the determination of cross-linking activation energies. Furthermore, a multistep mechanism of TPA cross-linking was proposed with strong evidence. The thermo-mechanical properties of cured networks were characterized using DMA, showing high cross-link densities and glass transition temperatures. Finally, these new thermosets displayed very high thermal performances under pyrolysis conditions (TGA).

International audience; Performing thermostable materials such as phenolic or epoxy networks are classically obtained from petrobased and harmful monomers. In this study, alternative solutions based on renewable eugenol trifunctional monomer (TEP) are proposed. Thus, innovative biobased Alder-ene thermosets are prepared by reacting TEP with two different bismaleimides: N,N′-1,3-phenylene bismaleimide (PhBMI) and polydimethylsiloxane bismaleimide (SiBMI) leading to different crosslinked aromatic networks. These materials exhibit various mechanical properties with very different T g values of −113 °C and 247 °C for SiBMI and PhBMI materials respectively. However, both thermosets exhibit excellent thermal properties with elevated degradation temperature and high char yield. The degradation behavior was studied using thermogravimetric analysis – Fourier transformed infrared spectroscopy (TGA-FTIR): only silicon compounds were observed for SiBMI, whereas phosphorus and carbonaceous products had specific signatures in degradation gases for PhBMI. Kinetic analysis of degradation confirmed those different behaviors. Our contribution with two original Alder-ene thermosets is an innovative way to develop sustainable versatile high-performant materials.

International audience; Eugenol, a natural phenol currently mainly obtained from clove oil, is an interesting aromatic building block for the synthesis of novel biobased monomers. It can also be obtained from lignin depolymerization, becoming a promising building block due to lignin availability as biomass feedstock. The synthesis of eight monomers derived from eugenol containing polymerizable functional groups is achieved. The (meth)acrylation of eugenol, isoeugenol, and dihydroeugenol is performed and the solution homopolymerization of these biobased monomers is studied. Moreover, aiming to prepare functional polymers, the introduction of epoxy and cyclic carbonate groups is executed via modification of the allylic double bond present in eugenol derived methacrylate. Thus, a novel platform of versatile biobased monomers derived from eugenol is presented, opening the opportunity to use them in a wide range of polymerization processes and applications

Chemistry in general, but polymer chemistry in particular has to face the major challenge of finding solutions to ensure a sustainable and environmental-benign development of industry to answer consumer needs. Aldehydes are very important chemical groups for polymer science of the synthesis of phenolic resins for example, however, most molecular aldehydes (such as formaldehyde) are toxic. Finding less toxic and sustainable aldehydes is not easy because this functional group is relatively scarce in nature. In consequence aldehydes-containing building blocks must be synthesized. The present review gives an overview of the different synthetic methods to prepare such aldehyde building blocks. It then focusses on the use of radically polymerizable aldehyde-containing monomers to prepare polymers and materials featuring available aldehyde pendent group. Indeed, owing to the rich reactivity and properties of aldehydes, such functional polymers will undoubtedly lead to the development of high-added value applications. This review also gives a brief overview of such potential applications.

Syntheses of novel hybrid PolyHydroxyUrethane (PHU)/siloxane polymers have been performed by sol-gel process in order to mix properties of organic and inorganic compounds. In the objective to replace Polyurethanes (PU) for environmental and health concern, Polyhydroxyurethanes (PHU) are becoming interesting candidates in Non-Isocyanate Polyurethanes (NIPUs) routes. Therefore, mixing PHU and siloxane monomers to synthesize hybrid organic/inorganic materials is a promising approach. In this way, Polyhydroxyurethanes prepolymers with trimethoxysilane end groups were firstly obtained via two synthetic pathways and finally cross-linked by sol-gel process. Trimethoxysilane groups can be grafted onto diamines or dicyclic-carbonates varying chemical structure and thus properties of final materials. Three different PHU hybrid bulk materials have been obtained and these thermosets have been characterized with DSC, ATG, SEM and DMA measurements.

The synthesis of polymers from renewable resources is largely investigated in a context of sustainable development. Polyepoxide networks, widely used in many applications, constitute a major class of thermosetting polymers synthesized from bisphenol A (BPA), a substance identified as chemical estrogen. Moreover, epichlorohydrin used to graft a glycidyl ether group onto BPA to yield diglycidyl ether of BPA (DGEBA) is very toxic. This review proposes to demonstrate that eugenol represents an asset in the development of sustainable epoxy thermosets, by giving a general approach of the researches on the use of eugenol and its isomers for the synthesis of epoxidized precursors. The syntheses of precursors with hetero atoms (nitrogen, phosphorus or silicon) used in specific applications in electrochemistry or as flame-retardants is compared to DGEBA materials.

Vinyl aromatic monomers derived from dihydroeugenol (EBM) and guaiacol (GBM) were copolymerized, via a miniemulsion process, with aliphatic monomers from high oleic soybean oil (HOSBM), yielding emulsion polymers with higher levels of biobased content. This fully renewable monomer feed generated a broad range of novel latexes, with the number-average molecular weight varying from 25,000–650,000 g/mol. Increasing the content of aromatic biobased monomers heightened the resulting latexes’ molecular weights due to the decreasing unsaturation degree (lower HOSBM content) in the reactive mixture. The monomer feed unsaturation effect was found to be more pronounced for latexes derived from EBMs and HOSBMs because EBMs are more reactive in free radical polymerization compared to GBMs. The presence of oil-derived unsaturated fragments in emulsion polymers provides an opportunity to crosslink resulting latexes in a controlled way to adjust the polymer networks’ thermomechanical properties. Thus, crosslinked films and coatings from latexes made of 25–90 wt.% EBM/GBM and 10–75 wt.% HOSBM were tested. This demonstrated that the characteristics of the resulting biobased latex materials are determined by the nature and ratio of the aliphatic oil residues from HOSBM and the aromatic fragments from EBM/GBM in the macromolecular backbone. Young’s modulus was also higher for the films with greater levels of EBM/GBM, while flexibility of the resulting polymeric materials was found to be determined by soft oil-derived copolymer content. For all films, hardness, impact resistance and adhesion to the steel substrate were evaluated. By combining the aliphatic fatty acid fragments of HOSBM with the aromatic EBM/GBM structure, durable latexes can be synthesized, with the ability to balance the thermomechanical properties of latex polymer networks over a broad range.