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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Hadjichristidis, Nikos
European Commission
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (15/15 displayed)
- 2024Interpenetrated and Bridged Nanocylinders from Self-Assembled Star Block Copolymerscitations
- 2024Controlled Ring‐Opening Polymerization of Methyl Glycolide with Bifunctional Organocatalystcitations
- 2023Poly(lactic acid) stereocomplexes based molecular architectures : synthesis and crystallization
- 2020Poly(vinylidene fluoride)-based Complex Macromolecular Architectures: From Synthesis to Properties and Applicationscitations
- 2019Generating Triple Crystalline Superstructures in Melt Miscible PEO-b-PCL-b-PLLA Triblock Terpolymers by Controlling Thermal History and Sequential Crystallizationcitations
- 2018CO 2 as versatile carbonation agent of glycosides: Synthesis of 5- and 6-membered cyclic glycocarbonates and investigation of their ring-openingcitations
- 2018Block Copolymers of Macrolactones/Small Lactones by a “Catalyst-Switch” Organocatalytic Strategy. Thermal Properties and Phase Behaviorcitations
- 2017A New Role for CO2: Controlling Agent of the Anionic Ring-Opening Polymerization of Cyclic Esterscitations
- 2017Self-assembly of Polystyrene- b -poly(2-vinylpyridine)- b -poly(ethylene oxide) Triblock Terpolymerscitations
- 2017Anionic Polymerization of Styrene and 1,3-Butadiene in the Presence of Phosphazene Superbasescitations
- 2016Metal-Free Alternating Copolymerization of CO2with Epoxides: Fulfilling “Green” Synthesis and Activitycitations
- 2016Well-defined 4-arm stars with hydroxy-terminated polyethylene, polyethylene-b-polycaprolactone and polyethylene-b-(polymethyl methacrylate) 2 armscitations
- 2016Ring-opening polymerization of ω-pentadecalactone catalyzed by phosphazene superbasescitations
- 2015Triblock and pentablock terpolymers by sequential base-assisted living cationic copolymerization of functionalized vinyl etherscitations
- 2009Solid state nanofibers based on self-assemblies:from cleaving from self-assemblies to multilevel hierarchical constructscitations
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article
A New Role for CO2: Controlling Agent of the Anionic Ring-Opening Polymerization of Cyclic Esters
Abstract
Conventional anionic ring-opening of polymerization (AROP) of cyclic esters suffers from the nonselective and concomitant attack of the monomer and of the polymer chains by the growing active species, which results in polyester samples with uncontrolled molar masses and broad polydispersity due to the competition between propagation and transesterification reactions. In this report, we describe a new AROP system mediated by a controlled amount of CO2 which prevents transesterification reactions from occurring. Using lithium monomethyl diethylene glycoxide (MEEOLi) as initiator and 1.5 equiv of CO2, ε-caprolactone could be polymerized under truly “living” conditions in dichloromethane (DCM) at 70 °C, as evidenced by the control of molar masses, the narrow polydispersity indexes (Mn up to ∼40 kg/mol, Đ < 1.16), and also successful chain extension experiments. Lithium carbonate used as initiator in the presence of 0.5 equiv of CO2 afforded similar polymerization results. Experiments carried out with other alkoxide salts and solvents demonstrate that CO2 is indispensable as well as lithium and noncoordinating solvents for the suppression of transesterifications. A similar strategy was applied for the AROP of l-lactide (LLA). At −20 °C, LLA could be polymerized under living conditions with undetectable level of transesterification as demonstrated by MALDI-ToF analysis. To account for the polymerization mechanism occurring in the presence of a slight excess of CO2, we resorted to computational studies. It appears that a fast equilibrium takes place between two tetrameric aggregates, one dormant comprising four carbonates (RCO3Li)4, and an active one involving three carbonates and one alkoxide (RCO3Li)3(ROLi). The latter is shown to selectively ring-open cyclic ester without indulging in transesterifications like (ROLi)4 precursors.