References of "Detrembleur, Christophe"
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See detailControlled synthesis of poly(vinylamine)-based copolymers by organometallic-mediated radical polymerization
Dréan, Mathilde ULg; Guégan, Philippe; Detrembleur, Christophe ULg et al

in Macromolecules (in press)

iving/controlled polymerization methods have enabled the synthesis of numerous (co)polymers with defined compositions and architectures. However, the precision design of poly(vinylamine)-based copolymers ... [more ▼]

iving/controlled polymerization methods have enabled the synthesis of numerous (co)polymers with defined compositions and architectures. However, the precision design of poly(vinylamine)-based copolymers remains challenging despite their extensive use in various fields of applications and the clear benefits to finely tune their properties. Here, we report on a two-step strategy for the synthesis of tailor-made poly(vinylamine) derivatives through the organometallic- mediated radical (co)polymerization (OMRP) of N-vinyl- acetamide and/or N-methylvinylacetamide followed by acid hydrolysis of the acetamide groups. A series of well-defined homopolymers as well as statistical and block copolymers with pendant primary and/or secondary amines having controlled molar masses, compositions, and low dispersities were produced accordingly. The reactivity ratios of the comonomers as well as the composition drift along the chain were determined in order to have a precise idea of the polymer structures. These advances represent a significant step toward an efficient platform for synthesis of this important class of amino group-containing (co)polymers. [less ▲]

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See detailOne-pot synthesis of double poly(ionic liquid) block copolymers by cobalt-mediated radical polymerization-induced self assembly (CMR-PISA) in water
Cordella, Daniela ULg; Debuigne, Antoine ULg; Jérôme, Christine ULg et al

in Macromolecular Rapid Communications (in press)

Amphiphilic double poly(ionic liquid) (PIL) block copolymers are directly prepared by cobalt- mediated radical polymerization induced self-assembly (CMR-PISA) in water of N-vinyl imida- zolium monomers ... [more ▼]

Amphiphilic double poly(ionic liquid) (PIL) block copolymers are directly prepared by cobalt- mediated radical polymerization induced self-assembly (CMR-PISA) in water of N-vinyl imida- zolium monomers carrying distinct alkyl chains. The cobalt-mediated radical polymerization of N-vinyl-3-ethyl imidazolium bromide (VEtImBr) is first carried out until high conversion in water at 30 °C, using an alkyl bis(acetylacetonate)cobalt(III) adduct as initiator and con- trolling agent. The as-obtained hydrophilic poly(N-vinyl-3- ethyl imidazolium bromide) (PVEtImBr) is then used as a macroinitiator for the CMR-PISA of N-vinyl-3-octyl imidazo- lium bromide (VOcImBr). Self-assembly of the amphiphilic PVEtImBr-b-PVOcImBr block copolymer, i.e., of PIL-b-PIL-type, rapidly takes place in water, forming polymer nanoparticles consisting of a hydrophilic PVEtImBr corona and a hydro- phobic PVOcImBr core. Preliminary investigation into the effect of the size of the hydrophobic block on the dimension of the nanoparticles is also described. [less ▲]

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See detailMerging carbon dioxide utilisation, bioresources and CO2-based process for sustainable low carbon footprints polyurethanes
Alves, Margot ULg; Grignard, Bruno ULg; Gennen, Sandro ULg et al

Poster (2016, June 29)

Making plastics more sustainable by valorizing waste CO2 as a cheap, inexhaustible and renewable feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic ... [more ▼]

Making plastics more sustainable by valorizing waste CO2 as a cheap, inexhaustible and renewable feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic driver for developing future low carbon footprints materials and technologies. With a global production estimated to 18 million tons for 2016, polyurethane (PU) is one of the most important polymers in our everyday life with applications in automotive, in building and construction, in coating, in the medical field, as flexible and rigid foams for thermal and/or acoustic insulation. Industrially, PU is produced by step-growth polymerization between di- or polyisocyanates and di- or polyols. However, isocyanates are extremely toxic compounds and made from even more toxic and explosive phosgene. Prolonged exposure to isocyanates vapour results in serious health damages such as skin irritation, asthma or DNA mutation whereas phosgene causes death. Because of the toxicity issues of these compounds associated to drastic changes in the REACH regulations limiting/banning the use of isocyanates, there is a need today to develop new greener and safer alternatives to produce PU. Valorising CO2 as C1 feedstock for producing precursors entering in the synthesis of polyurethanes by a non-isocyanate route (NIPU) is a promising route to solve this challenge the polyurethane sector is facing. Through its global objective focussing on the synthesis of isocyanate-free low carbon footprint foamed materials for thermal insulation this research highlights benefits of merging bio-resources with carbon dioxide transformation and “physical” utilization. The success of the project relies on 3 key steps involving: i) The synthesis of bio- and CO2-sourced cyclic carbonates using new highly efficient organocatalysts: Due to the low reactivity of CO2 versus epoxides, addition of catalysts in the reaction medium is necessary. If lot of catalysts have been developed, their use generally suffers from some drawbacks. Indeed, most of the metal-based catalysts are highly sensitive to hydrolysis and oxidation or/and poorly selective and additionally, some of them are toxic whereas less/non-toxic and eco-friendly organocatalysts such as ionic liquids and halide salts are generally only efficient at very high temperature and pressure, so favouring the decomposition of catalyst. To overcome these limitations, we developed a new highly-efficient bicomponent homogeneous organocatalyst that showed unexpected catalytic activity for the fast (within a few minutes) and selective addition of CO2 onto model epoxides and epoxidized vegetable oils under solvent-free and mild experimental conditions. The use of this powerful dual organocatalyst was further extended to the first organocatalytic coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonate entering the synthesis of CO2-sourced conventional PUs. ii) The synthesis of sustainable non-isocyanate polyurethanes: Sustainable NIPUs were produced by step-growth polymerization between the so-produced bio- and CO2-sourced cyclic carbonates and biosourced amino-telechelic comonomers derived from linseed fatty acids according to a process compatible with existing industrial infrastructures (extrusion). iii) The foaming of NIPUs: Sustainable foams with thermal insulation were produced by the supercritical CO2 assisted foaming technology. Due to its solubility in polymers, CO2 can replace conventional flammable VOCs and ozone depletion chemical or physical blowing agents such as diazo compounds, hydrocarbons (pentane, isopentane…) or inert gases (nitrogen…) to produce (ultra)lightweight microcellular foams. By finely choosing the CO2 impregnation and the foaming conditions, foams with a thermal conductivity as low as 0.052 Wm-1K-1 were produced. Our study shows that CO2 is not only sequestered in the material for long-term application, but is also valorized as a blowing agent in the production of sustainable thermally insulating NIPU foams. Such low carbon footprints materials will contribute to energy conservation and savings by reducing CO2 emissions [less ▲]

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See detailTransparent superhydrophobic coatings from amphiphilic-fluorinated block copolymers synthesized by aqueous polymerization-induced self-assembly
Ouhib, Farid ULg; Dirani, Ali; Aqil, Abdelhafid ULg et al

in Polymer Chemistry (2016), 7(24), 3998-4003

Preparation of transparent and superhydrophobic coatings by co-deposition of an aqueous solution of an amphiphilic fluorinated block copolymer (FBC) with silica particles was developped. Spin- coating of ... [more ▼]

Preparation of transparent and superhydrophobic coatings by co-deposition of an aqueous solution of an amphiphilic fluorinated block copolymer (FBC) with silica particles was developped. Spin- coating of this aqueous solution onto glass followed by an appropriate thermal treatment promotes the self-assembly of the hybrid material with the formation of superhydrophobic, robust and transparent coatings. [less ▲]

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See detailCatalytic transformation of CO2: from monomers to polymers
Alves, Margot ULg; Grignard, Bruno ULg; Boyaval, Amélie ULg et al

Conference (2016, May 24)

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable ... [more ▼]

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable molecule that can be converted into five membered cyclic carbonates by coupling with epoxides using organometallic complexes or organocatalysts. To date, the identification and development of highly efficient (organo)catalysts under mild experimental conditions still remains challenging. In particular, the synthesis of six membered cyclic carbonates by the CO2/oxetane coupling using such organocatalysts has never been reported to our knowledge. In this context, we developed a new highly efficient bicomponent homogeneous organocatalyst composed of an ammonium salt as the catalyst and fluorinated single or double hydrogen bond donor activators (HBD). First, the efficiency of this new organocatalyst for the fast and selective CO2/epoxide coupling was investigated through detailed kinetic studies by IR spectroscopy under pressure and results were compared with the most efficient organocatalysts reported in the literature. This study was completed by molecular modeling in order to elucidate the reaction mechanism. DFT calculations showed that the hexafluoroisopropanol functionalities of HBDs strengthened the proton donor capability and allowed a better stabilization by hydrogen bonding of the intermediates and transition states. Finally, the use of this dual organocatalyst was extended to the coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonates. [less ▲]

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See detailSynthesis of novel poly(vinylamine)-based copolymers with controlled compositions
Dréan; Guégan, Philippe; Detrembleur, Christophe ULg et al

Poster (2016, May 23)

Metal binding, pH sensitivity and polyelectrolytes complexation are key characteristics of amine-containing polymers. Among them, poly(vinylamine)s presenting high amine densities are particularly useful ... [more ▼]

Metal binding, pH sensitivity and polyelectrolytes complexation are key characteristics of amine-containing polymers. Among them, poly(vinylamine)s presenting high amine densities are particularly useful in many fields such as coatings , water purification and gas membrane separation. The properties of such polymers strongly depend on the nature of the amines and can thus be adjusted by incorporating different types of amines along the backbone. In this perspective, we developed a strategy for synthesizing poly(vinylamine)-based (co)polymers containing primary and secondary amines as well as imidazole moieties in predictable proportions. First, radical (co)polymerizations of N-vinylacetamide, N-methylvinylacetamide and vinylimidazole were performed followed by deprotection of the amine functions via acidic hydrolysis of the pendant amides. We determined the reactivity ratios of each comonomer pairs and developed the corresponding Skeist’s model, allowing the prediction of the copolymer compositions and distributions. Following this straightforward approach, novel amine-containing copolymers with predictable and precise compositions were made available and should contribute in the future to the development of the above-mentioned applications. [less ▲]

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See detailPolymers bearing pendant catechols for organic electrode-active materials in lithium-ion batteries
Patil, Nagaraj ULg; Cordella, Daniela ULg; Aqil, Abdelhafid ULg et al

Conference (2016, May 23)

Herein, we describe the synthesis and organometallic-mediated radical polymerization of 1-vinyl-3-alkylimidazolium-type monomers bearing pendant catechols in its protected version, using a presynthesized ... [more ▼]

Herein, we describe the synthesis and organometallic-mediated radical polymerization of 1-vinyl-3-alkylimidazolium-type monomers bearing pendant catechols in its protected version, using a presynthesized alkyl‒cobalt(III) complex as monocomponent initiator/mediating agent in a controlled fashion. A neat post-polymerization deprotection, followed by facile anion exchange reactions afforded a novel multi-functional poly(ionic liquids)-bearing free catechol functionalities. Prototype Lithium-ion battery, consisting a binder- and current collector-free electroactive polymer-supported buckypaper as the composite cathode, delivered an impressive specific capacity in the range of 199–230 mA h g‒1, relatively at high discharge potential = 3.2–3.4 V (vs Li/Li+), as calculated from CV and galvanostatic charge-discharge experiments. The superior electrochemical performance of the composite cathode consisting of PIL-catechols active-material, in comparison with poly(dopaminde acrylamide) is ascribed to the intrinsic Li-ion conductivity and enhanced surface activity of the imidazolium backbone with TFSI counteranion, compared to the acrylamide backbone. [less ▲]

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See detailFe2O3 nanoparticle-functionalized N-doped carbon with interconnected, hierarchical porous structures as high-performance electrode for lithium ion batteries
Alkarmo, Walid ULg; Ouhib, Farid ULg; Aqil, Abdelhafid ULg et al

Poster (2016, May 23)

Thanks to their fascinating physical properties such as high surface area, multidimensional electron transport pathways and good mechanical strength, three dimensionally (3D) interconnected carbon porous ... [more ▼]

Thanks to their fascinating physical properties such as high surface area, multidimensional electron transport pathways and good mechanical strength, three dimensionally (3D) interconnected carbon porous frameworks have emerged as attractive materials for various electrochemical energy storage/conversion devices, including Li-ion batteries (LIBs), Li−O2 batteries, Li−S batteries, supercapacitors, and fuel cells. A hierarchically structured macro- and mesoporous N-doped carbon with dispersed Fe2O3 nanoparticles (NDC@Fe2O3) is prepared by thermal treatment of a novel composite composed by PMMA particles decorated by graphene oxide (GO), PPy and iron salts. The NDC@Fe2O3 composite exhibited high surface area with a hierarchical pores structure. Integrated as a lithium ion battery anode, NDC@Fe2O3 exhibited high reversible capacity of 930 mA h/g over 200 cycles. The combination of Fe2O3 nanoparticles with porous carbon to form hybrid anode has been an efficient way to maintain the electronic integrity of the whole electrode since the carbon acts as a buffer layer to accommodate the volume variation and to provide multidimensional electron transport pathways during the charge/discharge process. [less ▲]

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See detailSynthesis of CO2-sourced hydrogels by using the non-isocyanate polyurethane (NIPU) chemistry
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

Poster (2016, May 23)

Polyurethane (PUs) is one of the most important polymers and finds applications as elastomers, coatings, adhesives and sealants for automotive or construction. PU is also a material of choice in the ... [more ▼]

Polyurethane (PUs) is one of the most important polymers and finds applications as elastomers, coatings, adhesives and sealants for automotive or construction. PU is also a material of choice in the biomedical domain due to its good biocompatibility, biodegradation and mechanical properties. Especially, PUs hydrogels have been developed in the last years for biomedical applications such as soft contact lenses, wound dressing, drug delivery systems and scaffolds for tissue engineering. Traditionally, PUs are synthesized by a step-growth polymerization between diols and diisocyanates. Because of toxicity issues and a possible interdiction of isocyanates, we focused on developing new PU hydrogels using a non-isocyanate route (Figure 1). The polyurethanes formed by this route are called NIPU (for Non-Isocyanate PolyUrethane). Firstly, chemically cross-linked NIPU gels were synthesized by solvent-free polycondensation between a hydrophilic CO2-sourced polyethyleneglycol bi-cyclic carbonate and a diamine in the presence of a crosslinker. Then, NIPU gels were swelled in water till water equilibrium before characterization of their mechanical properties by compression tests. The influence of the cross-linking ratios (diamine/crosslinker ratio) and diamine structure on the swelling and the compression properties were studied. To reinforce the compression properties of NIPU hydrogel (increase in stress at break, strain at break and compression modulus), a nanofiller was dispersed in the cyclic carbonate/diamine/crosslinker formulation prior to polymerization. For the first time, nanocomposite NIPU hydrogels with high water contents (up to 80%) and good compression properties have been prepared by using low clay content. [less ▲]

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See detailCyclic and oligo-carbonates by organocatalytic coupling of CO2 with epoxides or oxetanes
Alves, Margot ULg; Grignard, Bruno ULg; Boyaval, Amélie ULg et al

Conference (2016, April 20)

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable ... [more ▼]

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable molecule that can be converted into five and six membered cyclic carbonates by coupling with epoxides or oxetanes, respectively, using appropriate catalysts. Although transition metal catalysts are efficient under atmospheric pressure and ambient temperature, most of them are poorly selective, sensitive to hydrolysis and/or oxidation and/or toxic whereas less/non-toxic and eco-friendly organocatalysts such as ionic liquids and halide salts are generally only efficient at very high temperature and pressure favouring their thermal degradation. To overcome these limitations, we developed a new highly efficient bicomponent homogeneous organocatalyst composed of an ammonium salt as the catalyst and fluorinated single or double hydrogen bond donor activators. Through online FTIR kinetic studies, we demonstrated that this new organocatalyst showed unexpected catalytic activity for the fast and selective addition of CO2 onto epoxides under solvent-free and mild experimental conditions. The use of this dual catalyst was then extended to the coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonates. In the first part of this talk, based on kinetics of reactions followed by online FTIR under pressure, we will describe the reaction conditions required for the organocatalytic coupling of CO2 with epoxides and oxetanes. In the second part, the mechanism of the reaction will be approached and discussed based on DFT calculations. Finally, we will compare and discuss the efficiency of various organocatalytic systems for this type of reaction. [less ▲]

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See detailDirect one-pot synthesis of poly(ionic liquid) nanogels by cobalt-mediated radical cross-linking copolymerization in organic or aqueous media
Weiss-Maurin, Mathilde ULg; Cordella, Daniela ULg; Jérôme, Christine ULg et al

in Polymer Chemistry (2016), 7(14), 2521-2530

Nanogels of controlled kinetic chain length were synthesized by cobalt-mediated radical cross-linking copolymerization (CMRccP) involving a vinyl monomer and a divinyl cross-linker. This strategy was ... [more ▼]

Nanogels of controlled kinetic chain length were synthesized by cobalt-mediated radical cross-linking copolymerization (CMRccP) involving a vinyl monomer and a divinyl cross-linker. This strategy was first validated to achieve neutral poly(vinyl acetate) nanogels by CMRccP of vinyl acetate and divinyl adipate as cross-linker, at 40 °C, in presence of an alkyl- cobalt(III) serving both as initiator and controlling agent, using ethyl acetate as solvent. Poly(ionic liquid) nanogels were then directly obtained by CMRccP of N-vinyl-3-ethyl imidazolium bromide, in presence of 1,13-divinyl-3-decyl diimidazolium bromide as cross-linker. CMRccP experiments could be conducted either in organic solvent using dimethyl formamide or, more interestingly, in aqueous solution, demonstrating the robustness and the versatility of this one-step process. Chain extensions of PILs nanogels were also carried out in water, forming core-shell structures, thus opening new avenues in the design of functional nanogels. [less ▲]

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See detailPlasma deposition method for catechol/quinone functionalised layers
Detrembleur, Christophe ULg; Van de Weerdt, Cécile ULg; Vreuls, Christelle et al

Patent (2016)

The invention provides a solvent-free plasma method for depositing an adherent catechol and/or quinone functionalised layer to an inorganic or organic substrate from a precursor which comprises at least a ... [more ▼]

The invention provides a solvent-free plasma method for depositing an adherent catechol and/or quinone functionalised layer to an inorganic or organic substrate from a precursor which comprises at least a quinone group; a protected or unprotected catechol group; a molecule substituted by a quinone group and/or a protected or unprotected catechol group; and/or a natural or synthetic derivative of a catechol group and/or a quinone group; wherein the quinone group is a 1,2- benzoquinone group and the catechol group is a 1,2-dihydroxybenzene group. [less ▲]

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See detailCO2-blown microcellular non-isocyanate polyurethane (NIPU) foams: from bio- and CO2-sourced monomers to potentially thermal insulating materials
Grignard, Bruno ULg; Thomassin, Jean-Michel ULg; Gennen, Sandro ULg et al

in Green Chemistry (2016), 18(7), 2206-2215

Bio- and CO2-sourced non-isocyanate polyurethane (NIPU) microcellular foams were prepared using supercritical carbon dioxide (scCO2) foaming technology. These low-density foams offer low thermal ... [more ▼]

Bio- and CO2-sourced non-isocyanate polyurethane (NIPU) microcellular foams were prepared using supercritical carbon dioxide (scCO2) foaming technology. These low-density foams offer low thermal conductivity and have an impressive potential for use in insulating materials. They constitute attractive alternatives to conventional polyurethane foams. We investigated CO2’s ability to synthesize the cyclic carbonates that are used in the preparation of NIPU by melt step-growth polymerization with a bio-sourced amino-telechelic oligoamide and for NIPU foaming. Our study shows that CO2 is not only sequestered in the material for long-term application, but is also valorized as a blowing agent in the production of NIPU foams. Such foams will contribute to energy conservation and savings by reducing CO2 emissions. [less ▲]

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See detailNon-isocyanate polyurethanes from carbonated soybean oil Using monomeric or oligomeric diamines To achieve thermosets or thermoplastics
Poussard, Loïc; Mariage, J.; Grignard, Bruno ULg et al

in Macromolecules (2016), 49(6), 2162-2171

Fully bio- and CO2-sourced non-isocyanate polyurethanes (NIPUs) were synthesized by reaction of carbonated soybean oil (CSBO) either with biobased short diamines or amino-telechelic oligoamides derived ... [more ▼]

Fully bio- and CO2-sourced non-isocyanate polyurethanes (NIPUs) were synthesized by reaction of carbonated soybean oil (CSBO) either with biobased short diamines or amino-telechelic oligoamides derived from fatty acids to achieve respectively thermoset or thermoplastic NIPUs. Biobased carbonated vegetable oils were first obtained by metal-free coupling reactions of CO2 with epoxidized soybean oils under supercritical conditions (120 °C, 100 bar) before complete characterization by FTIR, 1H NMR, and electrospray ionization mass spectroscopy (ESI-MS). In a second step, biobased NIPUs were produced by melt-blending of the so-produced cyclocarbonated oil with the biobased aminated derivatives. The thermal and mechanical properties of resulting polymers were found to be depending on the cyclocarbonated vegetable oil/amine ratio. More precisely, short diamines and CSBO led to the formation of cross-linked NIPUs, and the resulting tensile and thermal properties were poor. In contrast, elastomeric NIPUs derived from oligoamides and CSBO exhibited a better rigidity, an improved elongation at break (εr up to 400%), and a higher thermal stability (T95 wt% > 350 °C) than those of starting oligoamides. These results are impressive and highlight the potentiality of this environmental friendly approach to prepare renewable NIPU materials of high performances. [less ▲]

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See detailPrecision of novel bio-based and ethylene-based copolymers: application to advanced nanocomposites
Scholten, Philip ULg; Detrembleur, Christophe ULg; Meier, Michaël et al

Conference (2016, March 18)

Polyolefins are an inexpensive class of compounds that can be used to prepare a plethora of different materials. Poly(ethylene) is the worldwide most produced polymer and is mostly synthesised by free ... [more ▼]

Polyolefins are an inexpensive class of compounds that can be used to prepare a plethora of different materials. Poly(ethylene) is the worldwide most produced polymer and is mostly synthesised by free radical polymerisation or catalytic coordination insertion using high temperature and pressure. The controlled radical polymerisation of ethylene is very difficult to achieve because of secondary reactions of this unconjugated monomer, e.g. chain transfer and termination reactions. Cobalt-mediated radical polymerisation (CMRP) represents a solution to control its polymerisation in mild conditions: in a reversible deactivation mechanism, a cobalt complex reversibly traps the active growing chains and converts them into dormant species, avoiding side reactions and allowing for a controlled polymerisation. Using CMRP, statistical copolymers of ethylene and vinyl acetate (VAc) have been synthesised, as well as block-like and block copolymers. Furthermore, functionalisation of the α- and ω-chain ends are now possible. Incorporating other monomers, e.g. vinyl esters or vinyl amides, into an ethylene copolymer by CMRP will lead to completely new and highly interesting materials which may act as compatibilisers for the dispersion of natural polymers, such as cellulose, into various polymer matrices. The goal of this work is to design novel well-defined functional polyethylenes that are expected to improve the dispersion of natural polymers into polyolefins. [less ▲]

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See detailCobalt-mediated radical polymerization of vinyl acetate and acrylonitrile in supercritical carbon dioxide
Kermagoret; Chau, Ngoc Do Quyen; Grignard, Bruno ULg et al

in Macromolecular Rapid Communications (2016), 39(6), 539-544

Cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc) is successfully achieved in supercritical carbon dioxide (scCO 2 ). CMRP of VAc is conducted using an alkyl-cobalt(III) adduct that is ... [more ▼]

Cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc) is successfully achieved in supercritical carbon dioxide (scCO 2 ). CMRP of VAc is conducted using an alkyl-cobalt(III) adduct that is soluble in scCO2 . Kinetics studies coupled to visual observations of the polymerization medium highlight that the melt viscosity and PVAc molar mass ( Mn ) are key parameters that affect the CMRP in scCO2. It is noticed that CMRP is controlled for M n up to 10 000 g mol−1 , but loss of control is progressively observed for higher molar masses when PVAc precipitates in the polymerization medium. Low molar mass PVAc macroinitiator, prepared by CMRP in scCO2 , is then successfully used to initiate the acrylonitrile polymerization. PVAc-b-PAN block copolymer is collected as a free flowing powder at the end of the process although the dispersity of the copolymer increases with the reaction time. Although optimization is required to decrease the dispersity of the polymer formed, this CMRP process opens new perspectives for macromolecular engineering in scCO2 without the utilization of fluorinated comonomers or organic solvents. [less ▲]

Detailed reference viewed: 67 (13 ULg)