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Proposing renewable structures for food packaging applications is necessary for contributing to a low-carbon and sustainable world. Thus, bio-based copolyesters, involving isosorbide (or isomannide), sebacoyl dichloride, and a second rigid acid structure (succinyl dichloride, isophthaloyl chloride or 2,6-pyridinedicarbonyl dichloride), were synthesized via polycondensation reactions. The values ranged from 10 600 to 18 000 g mol−1. 1H NMR spectroscopy established the random copolymerization and enabled the calculation of the respective monomer ratios in the copolymers. All copolyesters were thermally stable with Td5% higher than 328 °C and Tg ranging from 30 to 64 °C. The tensile test revealed plastic fractures for aliphatic copolyesters and brittle fractures for aromatic ones. The highest Young's modulus and tensile strength were obtained for aromatic copolyesters, whereas the largest elongation at break was observed for aliphatic ones. All copolyesters showed good gas barrier properties, and the best result was comparable to the widely used semi-crystalline PET.

Atopic dermatitis (AD) is a chronic disease in which epidermal barrier disruption triggers Th2-mediated eruption of eczematous lesions. Topical emollients are a cornerstone of chronic management. This study evaluated efficacy of two plant-derived oil derivatives, isosorbide di-(linoleate/oleate) (IDL) and isosorbide dicaprylate (IDC), using AD-like tissue culture models. Treatment of reconstituted human epidermis with cytokine cocktail (IL-4 + IL-13 + TNF-α + IL-31) compromised the epidermal barrier, but this was prevented by co-treatment with IDL and IDC. Cytokine stimulation also dysregulated expression of keratinocyte (KC) differentiation genes whereas treatment with IDC or IDL + IDC up-regulated genes associated with early (but not late) KC differentiation. Although neither IDL nor IDC inhibited Th2 cytokine responses, both compounds repressed TNF-α-induced genes and IDL + IDC led to synergistic down-regulation of inflammatory (IL1B, ITGA5) and neurogenic pruritus (TRPA1) mediators. Treatment of cytokine-stimulated skin explants with IDC decreased lactate dehydrogenase (LDH) secretion by more than 50% (more than observed with cyclosporine) and in vitro LDH activity was inhibited by IDL and IDC. These results demonstrate anti-inflammatory mechanisms of isosorbide fatty acid diesters in AD-like skin models. Our findings highlight the multifunctional potential of plant oil derivatives as topical ingredients and support studies of IDL and IDC as therapeutic candidates.

A new family of chiral selectors was synthesized in a single synthetic step with yields up to 84% starting from isomannide and isosorbide. Mono- or disubstituted carbamate derivatives were obtained by reacting the isohexides with electron-donating arylisocyanate (3,5-dimethylphenyl- or 3,5-dimethoxyphenyl-) and electron-withdrawing arylisocyanate (3,5-bis(trifluoromethyl)phenyl-) groups to test opposite electronic effects on enantiodifferentiation. Deeper chiral pockets and derivatives with more acidic protons were obtained by derivatization with 1-naphthylisocyanate and

The current trend of developing novel biobased polymeric materials is focused more on utilizing the unique structural/physical properties of renewable building blocks towards niche market applications. In this work, with the aim of developing low-crystallinity to amorphous polyesters with enhanced thermal properties, a series of copolyesters based on rigid and structurally asymmetric carbohydrate-derived building blocks, namely furan-2,5-dicarboxylic acid and isosorbide, and 1,4-butanediol were successfully synthesized using melt polycondensation. The copolyesters were obtained with varied chemical compositions and rather high molecular weights (Mn = 24 000–31 000 g mol−1) and intrinsic viscosities ([η] = 0.56–0.72 dL g−1). Incorporation of both building blocks significantly enhances the glass transition temperatures (Tg = 38–107 °C) of polyesters, and also efficiently inhibits the crystallization of the copolyesters. A low content of isosorbide (ca 10 mol%) leads to complete transition of the homopolyester to nearly fully amorphous materials. Detailed characterizations of the chemical structures and thermal properties of the synthesized copolyesters were conducted using various analytical techniques. In addition, hydrolytic and enzymatic degradations of the copolymers in the presence of porcine pancreatic lipase and cutinase were also investigated.

A series of regioisomeric isosorbide mono-epoxides, as well as diastereomerically pure mono-epoxy derivatives, have been prepared and studied. Anionic ring-opening polymerization of methoxy-capped monomers produced linear polyethers tethered with isosorbide units. These reasonably high molecular weight polymers exhibited glass transition temperatures at around 10–15 °C and thermal stability up to ∼300 °C, which indicated that the mono-epoxides are promising building blocks for well-defined biobased polymers.

Dimethyl isosorbide (DMI) is a well-known bio-based green replacement for conventional dipolar solvents such as dimethyl sulfoxide and dimethylformamide. The synthesis of DMI mainly relies on the etherification of the bio-based platform chemical isosorbide in the presence of basic or acid catalysts and by employing different alkylating agents. Among them, dimethyl carbonate (DMC) is considered one of the most promising for its good biodegradability and low toxicity. In this work, we report on a comprehensive investigation on high yielding methylation of isosorbide via DMC chemistry promoted by nitrogen organocatalyst N-methyl pyrrolidine (NMPy). Reaction conditions were optimized and then efficiently applied for the methylation of isosorbide epimers, isoidide and isomannide, and for some preliminary scale-up tests (up to 10 grams of isosorbide). The purification of DMI from the reaction mixture was achieved by both column chromatography and distillation at reduced pressure. NMPy demonstrated to be an excellent catalyst also for the one-pot conversion of D-sorbitol into DMI. Furthermore, for the first time, all seven methyl and methoxycarbonyl intermediates observed in the etherification of isosorbide were synthetised, isolated and fully characterised. This has provided an insight on the concurrent reaction pathways leading to DMI and on the role played by NMPy in the methylation of isosorbide. Finally, the reaction mechanisms for the methylation, methoxycarbonylation and decarboxylation promoted by NMPy partaking in the conversion of isosorbide into DMI via DMC chemistry have been proposed.

Isosorbide is a bio-based functional diol, which is prepared by sequential dehydration of sorbitol and widely used in plasticizers, monomers, solvents or pharmaceuticals. In this study, a variety of acidified Nb2O5 catalysts were prepared and used for the sequential dehydration of sorbitol to isosorbide. Acidification can effectively regulate the surface acidity of catalysts, which was measured by pyridine infrared spectroscopy and NH3-TPD analysis. The catalytic performance was related to the surface acidity, including the reaction temperature and the amount of catalysts. After optimization of reaction conditions, the yield of isosorbide reached 84.1% with complete sorbitol conversion during reaction at 150 °C for 3 h over 2 M sulfuric acid modified Nb2O5. Finally, the reaction mechanism regarding the role of Lewis acid sites was discussed. This study is of great significance for further development of an efficient catalytic system for the dehydration of carbohydrates to isosorbide.

Using the glucose derivatives isosorbide and glucarodilactone along with a castor oil derivative, 10-undecenoyl chloride, two monomers were synthesized: glucarodilactone undecenoate (GDLU) and isosorbide undecenoate (IU). These monomers were polymerized via acyclic diene metathesis (ADMET) polymerization to yield two homopolymers, P(GDLU) and P(IU), and two copolymers, P1(GDLU-co-IU) and P2(GDLU-co-IU), of similar number-averaged molecular weight and relative composition (51 and 61 kDa, Đ = 1.8 and 1.4, 46:54 and 52:48 mol percent). Comparison of the physical properties and degradation behavior of these polymers revealed divergent characteristics arising from differences in the nature of the carbohydrate building blocks. P(IU) is more thermally stable and has a lower glass transition temperature (Td = 369 °C, Tg = −10 °C) than P(GDLU) (Td = 206 °C, Tg = 32 °C) and P1,2(GDLU-co-IU) (Td = 210 and 203 °C, Tg = 1 and 7 °C). While all of the polymers were stable in acidic and neutral aqueous conditions, the tw...

Two renewable, structurally analogous monomers, isosorbide undecenoate (IU) and glucarodilactone undecenoate (GDLU) reacted with pentaerythritol tetrakis(3-mercaptopropionate) (PETT) via thiol-ene photopolymerization to form IU-PETT and GDLU-PETT thermosets. Despite their chemical similarity, uniaxial tensile testing showed that GDLU-PETT exhibited a strain-hardening behavior and is significantly tougher than IU-PETT. To understand this observation, in situ tensile testing and wide-angle X-ray scattering experiments (WAXS) were conducted. While the 2D WAXS patterns of IU-PETT displayed an isotropic halo during uniaxial deformation, they exhibited a change from an isotropic halo to a pair of scattering arcs for the GDLU-PETT samples. Density functional theory calculations further revealed that the GDLU alkyl chains are less angled than the IU alkyl chains. Based on these results, we postulate that the GDLU molecules can more easily order and align during uniaxial deformation, hence increasing intermolecular interactions between the GDLU molecules and contributing to the observed strain hardening behavior of their thermosets. This study exemplifies how molecules with subtle differences in their chemical structures can alter the structures and thermophysical properties of the resulting polymers in unpredictable ways.

We report the rapid, one-pot synthesis of functional polycarbonates derived from renewable alcohols (i.e., glucose tetraacetate, acetyl isosorbide, lauryl alcohol, and ethanol) and a cyclic carbonate bearing an imidazolecarboxylate. This tandem functionalization/ring-opening polymerization strategy can be performed on multigram scale and eliminates the need for rigorous purification and specialized equipment. A wide range of glass transition temperatures (

Increasing demand for isosorbide has led to the search for sustainable and efficient methods for its production from sorbitol, a biomass‐derived platform molecule. However, sorbitol dehydration to isosorbide is currently performed with mineral acids, resulting in safety and toxicity issues. Although some progress has been made towards replacement of liquid acids with heterogeneous catalysts, continuous systems with good stability, selectivity and productivity remain scarce. Herein, sorbitol dehydration to isosorbide is efficiently performed in a continuous, liquid‐phase plug flow reactor, utilising an acidic zeolite (H‐β (38)) as solid catalyst. H‐β (38) is shown to catalyse the reaction without loss of activity for 55 hours on stream, achieving an isosorbide productivity of 9670 gisosorbide/kgcatalyst. This value is 4 times greater than any other continuous process reported in literature to date, even though the reaction was terminated prior to any loss of activity being detected. Diagnostic kinetic studies reveal improved operational conditions, and characterisation of the post‐reaction catalyst is provided.

Triethylammonium hydrogen sulfate (TEAHS) has been employed as an inexpensive protic ionic liquid catalyst for the preparation of various biomass-derived renewable compounds. TEAHS efficiently catalyzed the esterification of biomass-derived chemical intermediates such as levulinic acid, 2-furoic acid, stearic acid, and isosorbide. The scalable, cosolvent-free preparations were conducted in a batch-type glass pressure reactor, which provided excellent yields (> 80%) of the esters under moderate conditions. The TEAHS catalyst was conveniently separated from the reaction mixture and reused without significant loss of activity.

International audience; The catalytic conversion of (ligno)cellulose is currently subject of intense research. Isosorbide is one of the interesting products that can be produced from (ligno)cellulose as it can be used for the synthesis of a wide range of pharmaceuticals, chemicals, and polymers. Isosorbide is obtained after the hydrolysis of cellulose to glucose, followed by the hydrogenation of glucose to sorbitol that is then dehydrated to isosorbide. The one-pot process requires an acid and a hydrogenation catalyst. Several parameters are of importance during the direct conversion of (ligno)cellulose such as the acidity, the crystallinity and the particle size of cellulose as well as the nature of the feedstocks. This review highlights all these parameters and all the strategies employed to produce isosorbide from (ligno)cellulose in a one-pot process. 1713

Acyclic diene metathesis (ADMET) polymerization of biobased α,ω-dienes of bis(undec-10-enoate) with diols (1,4-butanediol, isosorbide, isomannide, and 1,4-cyclohexanedimethanol) afforded high-molecular weight unsaturated polyesters, and subsequent tandem hydrogenation (H2 1.0 MPa, 50 °C, 3 h) gave the saturated polymers upon addition of a small amount of Al2O3 (1.0–1.7 wt %). Subsequent reaction of the unsaturated polymers with ethylene afforded the oligomers (by depolymerization and degradation).

Isosorbide is a diether diol readily available from starch, an abundant, renewable biomaterial. Because of its structure and functionality, it may serve as a base for the development of nontoxic po...

Isosorbide bis(methyl carbonate) (IBMC) is a scarcely studied green chemical with potential applications in the manufacturing of non-isocyanate polyurethanes and bisphenol A-free polycarbonates. Its synthesis by transesterification of isosorbide with dimethyl carbonate (DMC) is very negatively influenced by the presence of small amounts of acidic impurities in isosorbide when heterogeneous inorganic carbonates such as potassium and cesium carbonates are used as catalysts. In this paper it is shown that the problem can be solved by using homogeneous catalysts consisting of nitrogenated bases and superbases having a suitable dual nucleophilic–basic character and able to form a highly reactive acyl intermediate with the electrophilic reactant DMC. Cycloaliphatic secondary and tertiary amines, guanidines and amidines covering a nucleophilicity parameter (N) range between 13.58 and 20.58 in either acetonitrile or dichloromethane, and a pKa range in acetonitrile between 15.68 and 26.02 have been tested in batchwise mode. Highly active catalysts leading to hydroxyl conversions of 84–93% require a minimum N of 16 and a pKa ranging from 18.0 to 26.0. Within this pKa range, N must increase by about 0.5–0.6 units per each unit the pKa falls to keep the catalytic activity, indicating that nucleophilicity has approximately twice as much influence as basicity on the catalytic activity. One guanidine (TBD), one amidine (DBN) and three cycloaliphatic secondary amines (N-methylpyrrolidine, quinuclidine and DABCO) have been found to be excellent catalysts at 5 mol% vs. ISO. The side reaction leading to oligomer formation is not avoided, with oligomers, mainly the dimer, affording 6 wt% of the crude product independently of hydroxyl-conversion and catalyst type. This paper is a part of the research carried out within the VIPRISCAR project which has received funding from the Bio Based Industries Joint Undertaking (JU) under the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 790440. The JU receives support from the European Union's Horizon 2020 research and innovation programme and the Bio Based Industries Consortium. Thanks are due to research teams involved in VIPRISCAR project for valuable discussion during project meetings: Dr Stefaan De Wildeman et al. (B4Plastics, Belgium), Dr Yaying Chen et al. (Exergy, UK), Dr Daniel Klein et al. (Jowat SE, Germany), Mrs Elena Benedetti et al. (AEP Polymers, Italy), Dr Erasmo Cadena et al. (Vertech Group, France), Dr Jos´e-Mar´ıa Cuevas (Gaiker IK4, Spain) and Dr Sandra Medel (Leitat, Spain). Thanks are also due to Mr Robert Kirschbaum (SakuragiConsult) and Mr Alan Patrick Giles (Rawlings Giles), members of the VIPRISCAR's Advisory Board for valuable advices about market issues. Special acknowledgment is due to Dr Soraya Prieto (Tecnalia) for smooth project management.

The exo-hydroxyl group (exo-OH) on isosorbide (ISB) has long been asserted as a highly reactive moiety compared with the endo-hydroxyl group (endo-OH). In this study, calculations based on density functional theory and experiments without adding catalysts reveal that endo-OH has strong nucleophilic ability, and in the case of transesterification with diphenyl carbonate, the nucleophilic attack surmounts steric hindrance in rendering endo-OH more reactive than exo-OH. The kinetics of transesterification with different catalysts is investigated to determine the catalytic reactivity and molecular structure evolution. The results show that preferential activation of exo-OH moieties can be achieved either by reducing the coordination ability of catalytic cations (lg β1) or by enhancing the alkalinity of catalytic anions. Despite the low reactivity of exo-OH on ISB monomers, terminal exo-OH on carbonate oligomers exhibits higher reactivity than terminal endo-OH, justifying the experimental fact that ISB-based polycarbonates (ISB-PCs) are mostly terminated by endo-OH. Balancing the reactivity between endo-OH and exo-OH can be promoted by increasing the reaction temperature, thus accelerating transesterification to a high equilibrium constant. These findings help to clarify the mechanism of ISB transesterification and provide new strategies for the synthesis of high-molecular-weight ISB-PCs.

It is an immense challenge to design catalysts for synthesizing high molecular weight polycarbonates using CO2, CO2-based compounds, or biorenewable chemicals as building blocks. To this end, an eco-compatible approach to synthesizing polycarbonates from biorenewable isosorbide and CO2-derived dimethyl carbonate (DMC) has been exploited: the regulation of poly(isosorbide carbonate) molecular weight can be achieved by modifying the cation structure of ionic liquid (IL) catalysts. The hydrogen bond donating and accepting ability of ILs can be altered by adjusting the cation structure, which successfully leads to the tunability of the intrinsic imbalance reactivity of exo-OH and endo-OH in isosorbide. Moreover, these ILs exclusively activate the carbonyl carbon of DMC for accelerating the polymerization reaction. These features are appealing superiorities of ILs as compared to catalysts involving metallic elements. The [Emim]Br catalyst remarkably decreased the imbalanced reactivity of –OH groups of isosorbide, and exhibited the highest catalytic activity. With the presence of [Emim]Br, the poly(isosorbide carbonate) (PIC) weight-average molecular weight and glass transition temperature attained were 52 100 g mol−1 and 156 °C, respectively. Additionally, according to experimental results, DFT calculations, and in situ1H NMR analysis, a possible polymerization mechanism indicates that bromine-derived ILs participate in nucleophilic–electrophilic dual-activation in catalyzing PIC synthesis. Our work offers a direction to design catalysts for synthesizing PICs with higher molecular weights through an eco-compatible route.

Isosorbide is a versatile chemical intermediate for the production of a variety of drugs, chemicals, and polymers, and its efficient production from natural cellulose is of great significance. In this study, bifunctional catalysts based on niobium phosphates were prepared by a facile hydrothermal method and used for the direct conversion of cellulose to isosorbide under aqueous conditions. NH3-TPD analysis showed that a high acid content existed on the catalyst surface, and pyridine infrared spectroscopic analysis confirmed the presence of both Lewis acid and Bronsted acid sites, both of which played an important role in the process of carbohydrate conversion. XRD and H2-TPR characterization determined the composition and the hydrogenation centers of the catalyst. An isosorbide yield of 47% could be obtained at 200 °C for 24 h under 3 MPa H2 pressure. The Ni/NbOPO4 bifunctional catalyst retains most of its activity after five consecutive runs with slightly decreased isosorbide yield of 44%. In addition, a possible reaction mechanism was proposed that the synergistic effect of surface acid sites and hydrogenation sites was favorable to enhancing the cascade dehydration and hydrogenation reactions during the conversion of cellulose to isosorbide. This study provides as an efficient strategy for the development of novel multifunctional heterogeneous catalysts for the one-pot valorisation of cellulose.

Synthesis of bioderived high-molecular-weight polycarbonates under metal-free condition is particularly challenging. Here, a green synthetic strategy of bio-based poly(isosorbide carbonate) (PIC) from renewable monomer isosorbide (ISB) and dimethyl carbonate (DMC) was developed by using organo-catalysts, which avoided the use of toxic and metal-containing chemicals. Due to high catalytic activity of the organo-catalysts, the reactivity of ISB and selectivity of carboxymethylated products were improved significantly, resulting in high-molecular-weight PIC. By using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst, an oligomer with [–OC(O)OCH3]/[–OH] ratio of 1.56 and PIC with weight-average molecular weight of 53 200 were obtained, which indicated that both ISB and DMC were effectively activated by TBD according to our proposed bifunctional activation mechanism. Furthermore, one-pot synthesis of copolymeric poly(diol-co-isosorbide carbonate)s from ISB, DMC and various diols was achieved, where the secondary hydroxyl group of ISB and the primary hydroxyl group of diols were dually activated by TBD, which has not been reported to the best of our knowledge.

The four possible diheteropentalenes or bicyclic 5-5 ring-fused systems containing one non-bridgehead heteroatom in each ring are reviewed. Heteroatoms include oxygen, nitrogen, sulfur, selenium, tellurium, phosphorous, arsenic, antimony, and iodine. Fifteen new heterocyclic systems have been disclosed since 2008, although the reactions and synthesis of the pyrrolo[2,3-b]pyrrole system common in many natural products, including physostigmine, minfiensine, chimonanthine and psychotriasine, has attracted much attention. Reactions of conjugated and non-conjugated systems are described with many commencing from tryptamine and isosorbide. Highly conjugated adducts are considered in terms of aromaticity with several having semi-conductor properties.

Isosorbide bis(methyl carbonate) (IBMC) is a barely explored isosorbide derivative potentially useful as a monomer for synthesizing biobased polymers. In this paper, its synthesis by transesterification of isosorbide (IS) with dimethyl carbonate (DMC) at reflux temperature using potassium and cesium carbonates as catalysts is reported. Using a semicontinuous operation mode, a 97% yield was obtained with cesium carbonate as catalyst at a concentration of 0.2 mol% vs. IS, and a DMC/IS molar ratio of 30. Oligomerization by reaction between IS, the intermediate isosorbide mono(methyl carbonate) and IBMC is a severe competitive reaction. Oligomers formation is strongly suppressed at high molar ratios and low catalyst concentrations. Cesium carbonate leads to a lower oligomer formation than potassium carbonate which is explained by the “cesium effect”. Evidence of the usefulness of IBMC as a biobased monomer for polymer synthesis through its polycondensation with 1,4-butanediol (1,4-BDO) is provided. A poly(isosorbide-1,4-BDO carbonate) with a weight average molar mass of 1800 g/mol and a polydispersity of 1.43 is obtained in 63.4% yield using 3 mol% DBU vs. IBMC as a catalyst with an IBMC/1,4-BDO molar ratio of 1 at 130 °C. Keywords: Isosorbide, Isosorbide bis(methyl carbonate), Biobased monomers, Transesterification, Biobased polymers, Cesium carbonate effect

International audience; Isosorbide and its functionalized derivatives have numerous applications as bio-sourced building blocks. In this context, the synthesis of diols from isosorbide diallyl ether by hydrohydroxymethylation reaction is of extreme interest. This hydrohydroxymethylation, which consists of carbon-carbon double bonds converting into primary alcohol functions, can be obtained by a hydroformylation reaction followed by a hydrogenation reaction. In this study, reductive hydroformylation was achieved using isosorbide diallyl ether as a substrate in a rhodium/amine catalytic system. The highest yield in bis-primary alcohols obtained was equal to 79%.

International audience; The homopolymerization in basic conditions of the recently reported bis(γ-lactone), 2H-HBO-HBO, is herein described for the first time. The solvent-free polymerization of this pentafunctional levoglucosenone (LGO) derivative affords fully renewable poly(vinyl-ether lactone) copolymers with a highly hyperbranched structure. This investigation stems from the polycondensation trials between 2H-HBO-HBO and di(methyl carbonate) isosorbide (DCI) that fails to give the anticipated polycarbonates. Such unexpected behavior is ascribed to the higher reactivity of the 2H-HBO-HBO hydroxy groups toward its α,β-conjugated endocyclic C═C, rather than the DCI methylcarbonate moieties. The different mechanistic scenarios involved in 2H-HBO-HBO homopolymerization are addressed and a possible structure of poly(2H-HBO-HBO) is suggested. Furthermore, the readily accessible (S)-γ-hydroxymethyl-α,β-butenolide (HBO) is also polymerized for the first time at a relatively large scale, without any prior modification, resulting in a new hyperbranched polymer with an environmental factor (E factor) ≈0. These new HBO-based polymers have a great potential for industrial-scale production due to their interesting properties and easy preparation via a low-cost, green, and efficient process.

Upon copolymerization of carbohydrate-based cyclic moieties, they offer a variety of new functionalities and a convenient way to modify the properties of the material. Structurally the electronegative sites present in the cyclic structures have a major influence on hydrogen bonding. In this study the consequences of the incorpo- ration of 2,3:4,5-di-O-methylene-galactarate (GalXH) and 2,3:4,5-di-O-isopropylidene-galactarate (GalXMe) cy- clic moieties in aliphatic polyamides are investigated by FT-IR and solid state NMR and a correlation is made with the thermomechanical properties and crystallinity of the copolyamides. The analysis is complemented by the theoretical calculations, which suggest that the amide proton of such polyamides tends to form hydrogen bonds with the acetal oxygen of neighboring GalX (intramolecular) and therefore prevents the interchain hydrogen bonding, resulting in decreased hydrogen bonding density. Despite the conformational rigidity of the GalX comonomers, the decrease in interchain hydrogen bonding leads to a counter intuitive decrease in glass transition temperature with increasing mole percentage GalX comonomer. As suspected the copolymerization of GalX with aliphatic monomers suppresses the crystallinity which is more pronounced for bulkier monomers. ispartof: Polymer vol:226 status: published

International audience; Polyhydroxyalkanoates (PHAs) are a biodegradable and biobased family of bacterial polyesters with different architectures. Among them, the poly-3-hydroxybutyrate (PHB) is one of the most conventional and easily obtained by biotechnologies from different bioresources. However, this thermoplastic polyester known since more than 50 years presents until now only very limited applications due to a certain number of drawbacks such as poor mechanical properties, high degree of crystallinity, and low thermal stability. One major way to valorize this bacterial polyester could be to develop controlled building blocks for the synthesis of new generation of biobased polymers. In this way, short linear PHB diols oligomers (oligoPHB-diol) with controlled low molar masses have been successfully obtained from a new synthetic pathway using reactive solvents in a green way. Different transesterification reaction parameters were investigated to control the PHB molar mass decrease, such as the catalyst and reactive solvent contents, the temperature and the reactive solvent type. Obtained oligomers were then analyzed in detail and further incorporated into fully biobased thermoplastics. In this work, thermoplastic polyurethanes (TPU) were elaborated as an example of second-generation biobased thermoplastics. To obtain TPUs with high biobased content, a dimer fatty acid-based diisocyanate, the dimeryl diisocyanate, and another biobased diol, the isosorbide, were used. Two series of TPUs were prepared with (i) varying the isosorbide/oligoPHB-diol ratio, and (ii) different oligoPHB-diol molar mass. Materials were fully evaluated for their structural, thermal and mechanical properties, as well as their crystalline behavior. A large range of properties were obtained for these innovative thermoplastics which could open a large range of applications with a green and sustainable approach.

Carbohydrate-derived monomers were synthesized, and thiol–ene photopolymerization was employed to produce thermoset films and fibers from the biobased dienes isosorbide 10-undecenoate (IU) and glucarodilactone 10-undecenoate (GDLU) and multifunctional thiols. The resulting materials, comprising up to 94% biorenewable content, were flexible and cross-linked and had mechanical and thermal properties that varied with IU and GDLU content (e.g., rubbery plateau storage moduli = 6.1 to 10.5 MPa at 40 °C above the glass transition temperature; glass transition temperatures = −9.9 to 27 °C by differential scanning calorimetry; degradation temperatures = 238 to 347 °C by thermogravimetric analysis). By combining electrospinning with in-situ UV irradiation and carefully controlling the monomer mixture viscoelasticity and orifice-to-collector flight time, we produced uniformly cured fibers directly from the monomer feed when the ene monomers contained either 100% GDLU or 50% GDLU/50% IU. The resulting GDLU-containin...

Chitin is an attractive feedstock for the production of organonitrogen compounds. The hydrolysis of chitin produces N-acetylglucosamine, and subsequent hydrogenation gives a sugar alcohol, 2-acetamide-2-deoxysorbitol (ADS). However, the transformation of these compounds to useful chemicals has remained a challenge due to the complicated reactivity of the N-containing molecules. Here, we report the catalytic conversion of ADS to 2-acetamide-2-deoxyisosorbide (ADI), which is a potential platform chemical for the production of organonitrogen compounds such as polymers. This study shows that ADS hardly undergoes the dehydration condensation to ADI under the reaction conditions used for a widely studied dehydration reaction of a similar sugar alcohol, sorbitol. Instead, a large amount of a super strong acid, CF3SO3H, under vacuum conditions is required to produce ADI from ADS. Density functional theory calculations indicate that acetamide groups in the substrate trap acid protons, and therefore, a large amount...