References of "Jérôme, Christine"
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See detailAdvances in the use of CO2 as a renewable feedstock for the synthesis of polymers
Grignard, Bruno ULiege; Gennen, Sandro; Jérôme, Christine ULiege et al

in Chemical Society Reviews (in press)

Carbon dioxide offers an accessible, cheap and renewable carbon feedstock for synthesis. Current interest in the area of carbon dioxide valorisation aims at new, emerging technologies that are able to ... [more ▼]

Carbon dioxide offers an accessible, cheap and renewable carbon feedstock for synthesis. Current interest in the area of carbon dioxide valorisation aims at new, emerging technologies that are able to provide new opportunities to turn a waste into value. Polymers are among the most widely produced chemicals in the world greatly affecting the quality of life. However, there are growing concerns about the lack of reuse of the majority of the consumer plastics and their after-life disposal resulting in an increasing demand for sustainable alternatives. New monomers and polymers that can address these issues are therefore warranted, and merging polymer synthesis with the recycling of carbon dioxide offers a tangible route to transition towards a circular economy. Here, an overview of the most relevant and recent approaches to CO2-based monomers and polymers are highlighted with particular emphasis on the transformation routes used and their involved manifolds. [less ▲]

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See detailFast and facile one-pot one-step preparation of non-isocyanate polyurethane hydrogels in water at room temperature
Bourguignon, Maxime ULiege; Thomassin, Jean-Michel ULiege; Grignard, Bruno ULiege et al

in ACS Sustainable Chemistry and Engineering (in press)

Since the discovery of polyurethanes (PU) by Otto Bayer in 1937, PU hydrogels are still commonly produced by the polyaddition of nasty and toxic polyisocyanates with polyols in organic solvents or in the ... [more ▼]

Since the discovery of polyurethanes (PU) by Otto Bayer in 1937, PU hydrogels are still commonly produced by the polyaddition of nasty and toxic polyisocyanates with polyols in organic solvents or in the bulk, followed by their swelling in water. Their direct one-pot one-step synthesis in water is not possible due to the fast hydrolysis of isocyanates. The attractive greener variant for PU that consists in the polyaddition of poly(5-membered cyclic carbonate)s with polyamines is also suffering for a similar drawback (the hydrolysis of the cyclic carbonates), but also for the low reactivity of the reagents at room temperature. Herein, we report the first synthesis of PU hydrogels by a non-isocyanate route in water at room temperature from easily accessible CO2-sourced 5-membered cyclic carbonates (5CCs) and a commercially available polyamine. We demonstrate that PU hydrogels are now formed with impressive short gel times (15-20 min) provided that the pH is adjusted in the 10.5-11.5 range in order to limit 5CCs hydrolysis. Hydrogels of good mechanical properties and high swelling ability are prepared in a facile one-pot process. The robustness of the process is also illustrated by dispersing clays (natural or synthetic) or a natural hydrosoluble polymer (gelatin) in the formulation. These additives do not perturb the polymerization and enable to modulate the mechanical properties of the hydrogel. This works opens enormous perspectives in the design of elusive PU-based materials in water from largely accessible 5- membered cyclic carbonates. [less ▲]

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See detailA switchable domino process for the construction of novel CO2- sourced sulfur-containing building blocks and polymers
Ouhib, Farid; Grignard, Bruno ULiege; Van den Broeck, Elias et al

in Angewandte Chemie International Edition (in press)

alpha-alkylidene cyclic carbonates (aCCs) recently emerged as attractive CO2-sourced synthons for the construction of complex organic molecules. Herein, we report the transformation of aCCs into novel ... [more ▼]

alpha-alkylidene cyclic carbonates (aCCs) recently emerged as attractive CO2-sourced synthons for the construction of complex organic molecules. Herein, we report the transformation of aCCs into novel families of sulfur-containing compounds by organocatalyzed chemoselective addition of thiols, following a domino process that is switched on/off depending on the desired product. The process is extremely fast, versatile in substrate scope, provides selectively linear thiocarbonates or elusive tetrasubstituted ethylene carbonates with high yields following a 100% atom economy reaction, and valorizes CO2 as a renewable feedstock. It is also exploited to produce a large diversity of unprecedented functional polymers. It constitutes a robust platform for the design of new sulfur-containing organic synthons and important families of polymers. [less ▲]

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See detailOptimizing support properties of heterogeneous catalysts for the coupling of carbon dioxide with epoxides
Léonard, Géraldine L.-M.; Pirard, Sophie ULiege; Belet, Artium ULiege et al

in Chemical Engineering Journal (2019), 371

The study deals with the catalytic cyclocarbonation of epoxides to produce monomers used in the synthesis of polyurethane. A benchmark study of the textural properties of silica-based, doped or not ... [more ▼]

The study deals with the catalytic cyclocarbonation of epoxides to produce monomers used in the synthesis of polyurethane. A benchmark study of the textural properties of silica-based, doped or not, supports enabling the identification and optimization of the key parameters affecting the catalytic activity is reported. The results reveal that ammonium catalysts immobilized onto mesostructured supports with high surface area and low aggregation show better catalytic performances than analogue catalysts grafted onto microstuctured ones. While a high external surface area favours the grafting of ammonium salt, pore size must be large enough to enhance the accessibility of both carbon dioxide and epoxides to the catalytic sites. The activity of heterogeneous cat- alysts was evaluated for a model coupling reaction between carbon dioxide and propylene glycol diglycidylether. Using appropriated supports, cyclocarbonation yields are found to be higher in the presence of the hetero- geneous catalyst in comparison with the homogeneous one. These results allow to confirm the beneficial effect of the presence of residual OH silanol groups at the surface of the support, which activate epoxide through forming of hydrogen bonds. [less ▲]

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See detailHeterogenization of a cyclocarbonation catalyst: optimization and kinetic study
Léonard, Géraldine L.-M.; Belet, Artium ULiege; Grignard, Bruno ULiege et al

in Catalysis Today (2019), 334

Different types of heterogeneous catalysts designed for a cyclocarbonation reaction between an epoxidized source and CO2 under supercritical conditions have been synthesized. The process implied a ... [more ▼]

Different types of heterogeneous catalysts designed for a cyclocarbonation reaction between an epoxidized source and CO2 under supercritical conditions have been synthesized. The process implied a quaternization step where a (haloalkyl)trimethoxysilane reacted with tributylamine leading to a tributyl(trimethoxysilylalkyl)ammonium halide, with iodine and bromine as halogens. Then, a grafting step onto commercial fumed silica through condensation reaction between the silane part and Si-OH surficial groups provided the immobilized catalyst. The efficiency of grafting has been validated by liquid 1H NMR, solid 29Si NMR and TG-DSC-MS analyzes. The benchmark cyclocarbonation reaction of polyethylene glycol diglycidylether at 80 °C and 100 bar during 4 h showed that the best immobilized catalyst was tributylpropylammonium iodide (IC3Q-EH5). It has also been shown that immobilization provided -surprisingly !- better conversions than the corresponding homogeneous catalyst’s: this phenomenon has been explained through an epoxide-ring-opening activating effect thanks to Si-OH surficial groups. Furthermore, kinetic studies performed by in situ Raman spectroscopy on IC3Q-EH5 showed that temperature had a strong influence on the yield of the reaction while CO2 pressure had only a small effect. Recycling of the catalyst has also been considered, but no precise conclusions could be conducted because of the high catalyst dispersion. Finally, the addition of a fluorinated alcohol co-catalyst allowed obtaining a similar yield but at 80 °C and 55 bar during only 2,5 h with the best candidate. [less ▲]

Detailed reference viewed: 49 (21 ULiège)
See detailUpgrading CO₂ into novel families of regioregular and functional polymers
Grignard, Bruno ULiege; Gennen, Sandro; Ngassam Tounzoua, Charlène ULiege et al

Conference (2019, June 26)

Polycarbonates (PCs) and polyurethanes (PUs) belong to some of the world-leading polymers found in many of our daily life applications. PCs are mainly produced by polycondensation of alkylcarbonates ... [more ▼]

Polycarbonates (PCs) and polyurethanes (PUs) belong to some of the world-leading polymers found in many of our daily life applications. PCs are mainly produced by polycondensation of alkylcarbonates/phosgene derivatives with diols at high temperature, or by ring-opening polymerization of 5- or 6-membered cyclic carbonates while PUs are industrially made by polyaddition of diisocyanates with diols. Recent developments in the PUs field deal with the polyaddition of 5-membered dicyclic carbonates with diamines, but this polymerization is much slower compared to the isocyanate route and gave regio-irregular polymers of low molar mass due to the asence of selective ring-opening and the occurrence of side reactions. The polyaddition of dicyclic carbonates with diols would also be attractive to prepare PCs but is challenging due to the poor reactivity of the 5-membered cycles towards alcoholises. Until very recently, using a single 5-membered dicyclic carbonate platform to access various polymer families remained an elusive endeavour. In this talk, we will describe an innovative approach for the preparation of new families of PCs and PUs, by the facile room temperature polyaddition of novel activated CO2-sourced 5-membered biscyclic carbonates with diols (for PCs) or diamines (for PUs). These novel cyclic carbonates are prepared by organocatalyzed carboxylative coupling of CO2 with dialkynols. Although PCs require some organocatalyst to be produced, PUs synthesis do not require any activation. Moreover, this process allows for the synthesis of regioregular functional polymers free of defects and displaying high molar masses (Mn up to 100 kg/mol in some cases). The origin of this unprecedented reactivity will be explained as well as its impact on the polymer structure. We will also show that these novel CO2-sourced monomers can also be exploited to expand their scope of valorization to a fourth family of novel functional polymers, by tuning the nature of the comonomer. We believe that this platform of novel monomers is opening new perspectives in the facile production of novel and/or existing world-class relevant polymers by valorizing CO2 as a renewable feedstock. [less ▲]

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See detailInternational Conference on Carbon Dioxide Utilization (ICCDU)
Brege, Antoine ULiege; Méreau, Raphaël; Grignard, Bruno ULiege et al

Conference (2019, June 25)

The present research aims at investigating in details the reaction between carbon dioxide and a diol to afford cyclic and acyclic carbonates in moderate to good yields. Thanks to its chemical structure ... [more ▼]

The present research aims at investigating in details the reaction between carbon dioxide and a diol to afford cyclic and acyclic carbonates in moderate to good yields. Thanks to its chemical structure, CO2 has been identified as a promising reagent for the synthesis of organic carbonates as it is non-toxic, cheap and an abundant C1 renewable feedstock, and could potentially replace phosgene based carbonates produced industrially. Prior research has been focused on the epoxide/CO2 coupling to afford cyclic carbonates in good yields. Yet, this coupling suffers from limitations such as restricted substrates and exclusive synthesis of 5-membered cyclic carbonates. In order to extend the products availability through Carbon Dioxide Utilization, more recent research has been carried out with new substrates such as the use of diols. Although many different catalysts and reaction routes have already been investigated, efforts are still needed to identify cheaper and more efficient protocols for the selective synthesis of cyclic and acyclic carbonates from the coupling of CO2 with diols. In this context, the use of organic bases/alkylating agent dual system as promoters and low pressure and temperature conditions (P<1MPa, r.t) seem to be a good alternative to afford organic carbonates. The present work aims at providing, thanks to an in-situ ATR-IR spectroscopy monitoring, a detailed understanding of the synthesis of propylene carbonate from propylene glycol and CO2 promoted by DBU and the addition of alkyl halides. This analytical tool enabled to identify several reaction intermediates and to determine how the kinetic profiles, the reaction yields, and the selectivity of the reaction evolves with various parameters (pressure, temperature and nature of the base and alkyl halide). Thus, several experimental conditions have been tested as well as various alkyl halides in order to understand in details the effect on the selectivity and the efficiency of the reaction. Different substrates were also tested such as 1,x diols (2 ≤ x ≤ 4) and Isosorbide. The selectivity toward cyclic or biscarbonated compounds is discussed. Density Functional Theory (DFT) was also performed in this work to understand and validate the reaction pathways proposed via ATR-IR monitoring. Structures of transition states were optimized and comparisons between several reagents and/or paths were calculated, giving capital information about further enhancement of the CO2-diol conversion into carbonates. [less ▲]

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See detailPrecision design of vinyl amine and vinyl alcohol-based copolymers via cobalt-mediated radical polymerization
Stiernet, Pierre ULiege; Jérôme, Christine ULiege; Debuigne, Antoine ULiege

in Polymer Chemistry (2019), 10(23), 3055-3065

Poly(vinyl alcohol) (PVA) and poly(vinyl amine) (PVAm) are major industrial polymers involved in countless applications taking advantage of their ability to establish hydrogen bonds and, for the latter ... [more ▼]

Poly(vinyl alcohol) (PVA) and poly(vinyl amine) (PVAm) are major industrial polymers involved in countless applications taking advantage of their ability to establish hydrogen bonds and, for the latter, to create charges along the polymer’s backbone upon protonation. Although combining vinyl alcohol and vinyl amine units in specific proportions within copolymers should allow precise tuning of their properties and enlarge the scope of their use, the controlled synthesis of poly(VAm-co-VA)s has been completely dis- regarded so far. In this context, we report a straightforward strategy for preparing the aforementioned copolymers via cobalt-mediated radical copolymerization of vinyl acetate (VAc) and vinyl acetamide (NVA) followed by hydrolysis. Copolymerization conditions were optimized to produce poly(NVA-co-VAc) with predictable molar mass, low dispersity and precise composition. Reactivity ratios were also determined to gain insight into the distribution of the amine and alcohol moieties along the backbone. Depending on the hydrolysis treatment applied to poly(NVA-co-VAc), unprecedented well-defined poly(VAm-co-VA)s and poly(NVA-co-VA)s were achieved via full deprotection of the precursor and selective hydrolysis of its esters, respectively. [less ▲]

Detailed reference viewed: 29 (11 ULiège)
See detailCooperative catalysts for the selective synthesis of alkylidene cyclic carbonates from CO2 and propargylic alcohols
Ngassam Tounzoua, Charlène ULiege; Grignard, Bruno ULiege; Jérôme, Christine ULiege et al

Poster (2019, June)

Carbon dioxide (CO2) is a greenhouse gas responsible for global warming. In the last decades, efforts have been put towards the valorization of this abundant, nontoxic inexhaustible C1 source for the ... [more ▼]

Carbon dioxide (CO2) is a greenhouse gas responsible for global warming. In the last decades, efforts have been put towards the valorization of this abundant, nontoxic inexhaustible C1 source for the synthesis of useful commodity chemicals such as methanol, methane, carboxylic acids, urea, synthetic fuel and cyclic carbonates. Amongst those, the synthesis of cyclic carbonates is attracting much interest due to its 100% atom efficiency reaction and its large potential scope for the design of complex organic molecules or novel functional polymers (polycarbonates, polyurethanes, etc.). 5-membered cyclic carbonates can be obtained by the coupling of CO2 with diols, epoxides and lastly, alkynols. The latter have the advantage of affording cyclic carbonates that are activated by the presence of an exocyclic vinylic bond, making them reactive towards alcohols and amines. In addition, their ring-opening is regio-selective affording β-oxo-carbonate by reaction with alcohols, ß-oxo-urethanes with secondary amines or ß-hydroxy-oxazolidones with primary amines. Due to the inertness and high thermodynamic stability of CO2, a catalyst is required to transform alkynols into alkylidene cyclic carbonates. Bases, ionic liquids), carbenes, metal salts, have been shown to promote the cyclisation of CO2 with alkynols. Although full conversions are obtained in certain cases, the selectivity remains an issue. Also, harsh conditions and/or excessive amounts of base are often used. In this work, we designed novel, cheap, highly efficient organocatalysts for the synthesis of α-alkylidene cyclic carbonates from CO2 and alkynols. Several organocatalysts, based on ammonium cations and basic anions were screened, and kinetic studies were performed by Raman spectroscopy to identify the best anion/cation couple. We further optimized our catalytic system by developing cooperative catalysts providing conditions for the selective formation of α-alkylidene cyclic carbonates under mild experimental conditions and short reaction times at very low catalyst loading. [less ▲]

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See detailPolymers bearing catechol pendants as universal hosts for aqueous rechargeable H+, Li-ion, and post-Li-ion (mono‑, di‑, and trivalent) batteries
Patil, Nagaraj; Mavrandonakis, Andreas; Jérôme, Christine ULiege et al

in ACS Applied Energy Materials (2019), 2(5), 3035-3041

Organic electrode materials capable of reversible coordination/uncoordination of both mono- and multivalent ions in aqueous electrolytes are desired to develop safe, sustainable, and cost-effective water ... [more ▼]

Organic electrode materials capable of reversible coordination/uncoordination of both mono- and multivalent ions in aqueous electrolytes are desired to develop safe, sustainable, and cost-effective water-based batteries. Here, we demonstrate the universality of bioinspired redox-active polymers bearing catechol pendants to reversibly coordinate/uncoordinate numerous cations including H+ and Li+ to Zn2+ and Al3+ with fast kinetics and ultralong cyclability. This unprecedented versatility is based on a catecholato–metal cation complex (Cat2–(mMn+)) charge storage mechanism that dictates the overall electrochemistry: formation of stronger complexes in M+ < M2+ < M3+ order resulted in a huge redox potential increment that might be used to tune the operating voltage of the battery. [less ▲]

Detailed reference viewed: 25 (6 ULiège)
See detailSynthesis of new PLGA based grafted polymers for formation of bioactive nanoparticles
Toullec, Clément; Boury, Frank; Grignard, Bruno ULiege et al

Poster (2019, May 27)

The loss of bone tissues because of age, obesity, trauma or diseases can provoke a significant morbidity and an important socio-economical cost. During the last few decades, tissue engineering and ... [more ▼]

The loss of bone tissues because of age, obesity, trauma or diseases can provoke a significant morbidity and an important socio-economical cost. During the last few decades, tissue engineering and regenerative medicine have become promising strategies for rebuilding bones. The tissue engineering of bones has for objective the functional regeneration of bones through a synergetic combination of biomaterial scaffolds, cells and active biomolecules such as proteins, peptides or growth factors. The objective of our work was to synthesize a copolymer, curdlan-graft-PLGA, in supercritical CO2 without any organic solvent. This copolymer was then used for the formulation of nanoparticles that are intended to be loaded with bioactive molecules for bone regeneration. Starting with cyclic monomers, glycolide and lactide, poly-lactic-co-glycolic acid (PLGA) was obtained through ring-opening polymerization (ROP) in supercritical carbon dioxide (scCO2). Curdlan (1,3-β-glucan), a polysaccharide, was used as an initiator. Organic catalysers, including 1,8-diazabicyclo[5.4.0]undec-7-ene and thio-urea, were also used. The purity, composition and molecular mass of the curdlan-graft-PLGA copolymer were determined with liquid NMR. Nanoparticles were prepared through a phase separation method. The copolymer was dissolved in dimethyl isosorbide (DMI), then an anti-solvent, an aqueous solution of glycine and NaOH, was progressively added in large excess. The average nanoparticle size was determined by dynamic light scattering. The morphology of nanoparticles was studied with scanning and transmission electronic microscopy. Finally, the zeta potential was also measured. In this work, we used curdlan both as an initiator for the ROP and as a backbone for the copolymerization with PLGA. Thus, the resulting curdlan-graft-PLGA copolymer is composed of PLGA chains grafted on the curdlan backbone. scCO2 is considered as a “green” solvent because its critical pressure and temperature are relatively low, it is abundant, inert, nontoxic and non-flammable. Therefore, the ROP in scCO2 allows to obtain the curdlan-graft-PLGA copolymer in one step without any toxic solvent. Moreover, the synthesis parameters were optimised to diminish the amount of organocatalysts used. The rate of conversion of this process was determined to be of 98% and the molar mass of the PLGA grafts synthesised of 10 000g.mol-1. Nanoparticles were formed using this copolymer via a method of nanoprecipitation by phase separation. This method uses the difference in hydrophilicity between PLGA and curdlan. Curdlan is more hydrophilic than PLGA, therefore it will be preferentially oriented toward the aqueous phase on the surface of the nanoparticles while the PLGA will find itself in the core. This configuration was confirmed by modifying the quantity of curdlan in the copolymer which leads to a difference in the zeta potential of nanoparticles. The particles were observed to be spherical with a diameter of 300 nm in average and a polydispersity index of 0.2. [less ▲]

Detailed reference viewed: 22 (1 ULiège)
See detailMechanistic and kinetic insight into the carbonatation reaction of diols to afford (a)cyclic carbonates: toward CO2-based monomers
Brege, Antoine ULiege; Méreau, Raphaël; Grignard, Bruno ULiege et al

Poster (2019, May 27)

The present research aims at investigating in details the reaction between carbon dioxide and a diol to afford cyclic and acyclic carbonates in moderate to good yields. Thanks to its chemical structure ... [more ▼]

The present research aims at investigating in details the reaction between carbon dioxide and a diol to afford cyclic and acyclic carbonates in moderate to good yields. Thanks to its chemical structure, CO2 has been identified as a promising reagent for the synthesis of organic carbonates as it is non-toxic, cheap and an abundant C1 renewable feedstock, and could potentially replace phosgene based carbonates produced industrially. These organic carbonates are key intermediates for the production of aliphatic polycarbonates, which have regained more and more attention over the past decades. Thus, developing tools for the synthesis of CO2-based carbonates as monomers is of high interest. Prior research has been focused on the epoxide/CO2 coupling to afford cyclic carbonates in good yields. Yet, this coupling suffers from limitations such as restricted substrates and exclusive synthesis of 5-membered cyclic carbonates. In order to extend the products availability through Carbon Dioxide Utilization, more recent research has been carried out with new substrates such as the use of diols. Although many different catalysts and reaction routes have already been investigated, efforts are still needed to identify cheaper and more efficient protocols for the selective synthesis of cyclic and acyclic carbonates from the coupling of CO2 with diols. In this context, the use of organic bases/alkylating agent dual system as promoters and low pressure and temperature conditions (P<1MPa, r.t) seem to be a good alternative to afford organic carbonates. The present work aims at providing, thanks to an in-situ ATR-IR spectroscopy monitoring, a detailed understanding of the synthesis of propylene carbonate from propylene glycol and CO2 promoted by DBU and the addition of alkyl halides. This analytical tool enabled to identify several reaction intermediates and to determine how the kinetic profiles, the reaction yields, and the selectivity of the reaction evolves with various parameters (pressure, temperature and nature of the base and alkyl halide). Thus, several experimental conditions have been tested as well as various alkyl halides in order to understand in details the effect on the selectivity and the efficiency of the reaction. Different substrates were also tested such as 1,x diols (2 ≤ x ≤ 4) and Isosorbide. The selectivity toward cyclic or biscarbonated compounds is discussed. Density Functional Theory (DFT) was also performed in this work to understand and validate the reaction pathways proposed via ATR-IR monitoring. Structures of transition states were optimized and comparisons between several reagents and/or paths were calculated, giving capital information about further enhancement of the CO2-diol conversion into carbonates. [less ▲]

Detailed reference viewed: 20 (2 ULiège)
See detailSupercritical CO2 foaming of PCL covalent networks : taking benefit from the thermo-reversible Diels-Alder cycloaddition
Houbben, Maxime ULiege; Malherbe, Cédric ULiege; Thomassin, Jean-Michel ULiege et al

Poster (2019, May 27)

Foams are versatile materials encountered in our daily life for a wide variety of uses such as cushioning, thermal and acoustic insulation or medical applications. The combination of the mixed properties ... [more ▼]

Foams are versatile materials encountered in our daily life for a wide variety of uses such as cushioning, thermal and acoustic insulation or medical applications. The combination of the mixed properties between a continuous matrix and gas cells and the diversity of pore structures represent a powerful tool for the design of new materials. Among the different polymer foam fabrication processes, the use of supercritical CO2 has been one of the most investigated in the past decade. Nevertheless, the design of crosslinked polymer foams with high foaming ratio still remains a challenge. Various crosslinking processes mainly based on heating, irradiation with the addition of an external agent have been applied after foaming but remain difficult to perform due to mass transfer issues of the crosslinking agent. When crosslinking occurs before foaming, it dramatically limits the material expansion. In order to overcome these drawbacks, the present work aims taking advantage of the thermoreversible Diels-Alder cycloaddition to elaborate foams of poly(ε-caprolactone) (PCL) covalent networks. Based on this reaction, we considered to induce cross-linking after the foam expansion by playing on the thermal equilibrium of the thermoreversible Diels-Alder cycloaddition. Therefore, low molar mass star-shaped PCL end-capped by furan or maleimide were impregnated with CO2 under supercritical conditions and then foamed under appropriate control of the pressure and temperature. Annealing about 2h at 40°C allows Diels-Alder adducts to be formed and a stable PCL network keeping at least 80% of the expanded volume is obtained. The resulting foam possesses a much higher volume expansion than a pre-crosslinked sample foamed in the same conditions, thanks to the low crosslinking ratio during foaming. These foams exhibit also improved thermal stability thanks to its chemical crosslinking as compared to non-crosslinked PCL foams. Interestingly, these foams possess shape memory properties due to the semi-crystallinity of the PCL. Thermal stability and shape memory properties were evaluated by dynamic mechanical analysis in both tensile and compression testing with controlled force mode, stress and temperature ramps. [less ▲]

Detailed reference viewed: 24 (2 ULiège)
See detailEfficient moisture-sensitive shape-memory materials composed of supramolecular network of poly(ε-caprolactone) and poly(ethylene oxide)
Caprasse, Jérémie ULiege; Thomassin, Jean-Michel ULiege; Riva, Raphaël ULiege et al

Poster (2019, May 27)

Shape-memory polymers (SMPs) are remarkable stimuli-responsive materials able to switch from one stable macroscopic shape to another one, which can find application as smart medical devices. For this ... [more ▼]

Shape-memory polymers (SMPs) are remarkable stimuli-responsive materials able to switch from one stable macroscopic shape to another one, which can find application as smart medical devices. For this purpose, covalent crosslinked poly(ε-caprolactone) (PCL) is widely studied because it is biocompatible, degradable, exhibits efficient thermally triggered shape memory properties, i.e. high fixity of the temporary shape, high recovery of the permanent shape and has good mechanical properties. In this work, an hydrophilic component, i.e. poly(ethylene oxide), is introduced into PCL networks in order to impart an additional shape transition triggered by hydration of the material at constant temperature. The network of both materials is formed by reaction of the maleimide end-capped PCL stars with furan end-capped PEO stars. After melt-mixing and a post-curing of 48h, this material shows high crosslinking density as demonstrated by swelling behavior, good mechanical properties and excellent shape memory properties,. Moreover, moisture triggered shape transition is observed in addition to conventional thermal shape memory properties. [less ▲]

Detailed reference viewed: 16 (2 ULiège)
See detailSynthesis of supramolecular networks of poly(e-caprolactone) and poly(ethylene oxide) as moisture sensitive shape-memory materials
Caprasse, Jérémie ULiege; Thomassin, Jean-Michel ULiege; Riva, Raphaël ULiege et al

Poster (2019, May 23)

Shape-memory polymers (SMPs) are remarkable stimuli-responsive materials able to switch from one stable macroscopic shape to another one, which can find application as smart medical devices. For this ... [more ▼]

Shape-memory polymers (SMPs) are remarkable stimuli-responsive materials able to switch from one stable macroscopic shape to another one, which can find application as smart medical devices. For this purpose, the covalent crosslinked poly(ε-caprolactone) (PCL) is widely studied because it is biocompatible, degradable, exhibit efficient thermally triggered shape memory properties, i.e. exhibit high fixity of the temporary shape and high recovery of the permanent shape and has good mechanical properties. In this work, an hydrophilic component, i.e. poly(ethylene oxide), is introduced into PCL networks in order to impart an additional shape transition triggered by hydration of the material at constant temperature. The network of both materials is formed by reaction of the maleimide end-capped PCL stars with and furan end-capped PEO stars. This material exhibits high crosslinking density and excellent shape memory properties, after a post-curing of 48h. Moisture triggered shape transition is observed in addition to conventional thermal shape memory properties. [less ▲]

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See detailCO2-sourced polycarbonates as solid electrolytes for room temperature operation lithium battery
Ouhib, Farid; Meabe, Leire; Mahmoud, Abdelfattah ULiege et al

in Journal of Materials Chemistry A (2019), 7(16), 9844-9853

In the last years, polycarbonates have been identified as alternatives to poly(ethylene oxide) as polymer electrolytes for lithium battery applications. In this work, we show the design of CO2-sourced ... [more ▼]

In the last years, polycarbonates have been identified as alternatives to poly(ethylene oxide) as polymer electrolytes for lithium battery applications. In this work, we show the design of CO2-sourced polycarbonates for its use in a room temperature lithium battery. Novel functional polycarbonates alternating oxo-carbonate moieties and polyethylene oxide segments are synthesized by the facile room temperature (rt) organocatalyzed polyaddition of CO2-sourced bis(?-alkylidene carbonate)s (bis-?CCs) with polyethylene oxide diols. The effect of the polyethylene oxide molar mass on the ionic conductivity and on the thermal properties of the poly(oxo-carbonate)s is investigated. The best candidate shows a low glass temperature of -44°C and a high ionic conductivity of 3.75 * 10-5 S cm-1 at rt when loaded with 30 wt% bis(trifluoromethanesulfonyl)imide salt (LiTFSI) without any solvent. All solid semi-interpenetrated network polymer electrolyte (SIN-SPE) is then fabricated by UV-cross-linking of a mixture containing a specifically designed poly(oxo-carbonate) bearing methacrylate pendants, diethylene glycol diacrylate and the previously described poly(oxo-carbonate) containing LiTFSI. The resulting self-standing membrane exhibits a high oxidation stability up to 5 V (vs Li/Li+), an ionic conductivity of 1.1 * 10-5 S cm-1 at rt (10-4 S cm-1 at 60°C) and promising mechanical properties. Assembled in a half cell configuration with LiFePO4 (LFP) as cathode and lithium as anode, the all-solid cell delivers a discharge capacity of 161 mAh g-1 at 0.1C and 60°C, which is very close to the theoretical capacity of LFP (170 mAh g-1). Also, a stable reversible cycling capacity over 400 cycles with high coulombic efficiency of 99 % is noted at 1C. Similar results are obtained at rt provided that 10 wt% of tetraglyme as plastisizer were added to SIN-SPE. I. [less ▲]

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See detailGas-Phase Dynamics of Collision Induced Unfolding, Collision Induced Dissociation, and Electron Transfer Dissociation-Activated Polymer Ions
Haler, Jean ULiege; Massonnet, Philippe ULiege; Far, Johann ULiege et al

in Journal of the American Society for Mass Spectrometry (2019), 30(4), 563572

Polymer characterizations are often performed using mass spectrometry (MS). Aside from MS and different tandem MS (MS/MS) tech- niques, ion mobility–mass spectrometry (IM-MS) has been recently added to ... [more ▼]

Polymer characterizations are often performed using mass spectrometry (MS). Aside from MS and different tandem MS (MS/MS) tech- niques, ion mobility–mass spectrometry (IM-MS) has been recently added to the inventory of char- acterization technique. However, only few studies have focused on the reproducibility and robust- ness of polymer IM-MS analyses. Here, we per- form collisional and electron-mediated activation of polymer ions before measuring IM drift times, collision cross-sections (CCS), or reduced ion mobilities (K0). The resulting IM behavior of different activated product ions is then compared to non-activated native intact polymer ions. First, we analyzed collision induced unfolding (CIU) of precursor ions to test the robustness of polymer ion shapes. Then, we focused on fragmen- tation product ions to test for shape retentions from the precursor ions: cation ejection species (CES) and product ions with m/z and charge state values identical to native intact polymer ions. The CES species are formed using both collision induced dissociation (CID) and electron transfer dissociation (ETD, formally ETnoD) experiments. Only small drift time, CCS, or K0 deviations between the activated/formed ions are observed compared to the native intact polymer ions. The polymer ion shapes seem to depend solely on their mass and charge state. The experiments were performed on three synthetic homopolymers: poly(ethoxy phosphate) (PEtP), poly(2-n-propyl- 2-oxazoline) (Pn-PrOx), and poly(ethylene oxide) (PEO). These results confirm the robustness of polymer ion CCSs for IM calibration, especially singly charged polymer ions. The results are also discussed in the context of polymer analyses, CCS predictions, and probing ion–drift gas interaction potentials. [less ▲]

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