MACROMOLECULAR ENGINEERING AND ENERGY

Research Group Leader : Pr Olivier Coulembier

Phone :+32(0)65.37.34.81

Secretariat : +32(0)65.37.34.83

The interest of our research is mainly focused on the preparation of (biocompatible/biodegradable) polymers presenting complex architectures. Specific initiators, living/controlled polymerization procedures, quantitative organic transformations and new monomers are prepared in our group and used for the construction of complex materials including cyclic, star-shaped, dendrimer-like star or hyperbranched architectures. For the sake of greening the chemistry, our approach relies on a biomimetic inspiration from Nature. By corollary, the activation of carbon dioxide to enable its use as a synthon or a participating polymerization molecule is arousing our interest.”

Projects :

  • SOLIDYE (EU, Région wallonne)
  • BIORGEL (EU, Région wallonne)
  • SUSPOL : EU
  • BIODEST : EU
  • BATWAL : Région wallonne
  • HYB2HYB : Région wallonne

Top selected papers

Organocatalysis Applied to the Ring-Opening Polymerization of b-Lactones: A Brief Overview.

Abstract Metal-free initiating systems present indisputable advantages in the ring-opening polymerizations of various b-lactones for the preparation of poly(hydroxyalkanoate)s. These have been presented in the following highlight focusing on the types of mechanisms involved as well as the advantages and drawbacks of the different technics. More information
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Metal-free Synthesis of Poly(trimethylene carbonate) by Efficient Valorization of Carbon Dioxide.

Abstract The desire for sustainability drives interest in the production of chemicals from carbon dioxide. The synthesis of poly(trimethylene carbonate), PTMC, by copolymerization of carbon dioxide and oxetane using organocatalysis affords a green route to this important polymer but has proven to be a very challenging process. Herein we report that the application of iodine, in combination with organic superbases provides a highly active system for the direct synthesis of PTMC from CO2 with very high levels of carbonate linkage (95 % in selectivity). Mechanistic studies reveal the in-situ formation of trimethylene carbonate which eventually polymerizes through an active chain-end process from an I2-oxetane adduct. More information
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Isoselective Ring-Opening Polymerization of rac-Lactide From Chiral Takemoto’s Organocatalysts: Elucidation of Stereocontrol.

Abstract We report that both commercially available (R,R)- and (S,S) enantiomers of chiral thiourea-amine Takemoto’s organocatalysts promote efficient control and high isoselectivity at room temperature of the ring-opening polymerization (ROP) of racemic lactide by kinetic resolution, yielding highly isotactic, semi-crystalline and metal-free polylactide (PLA). More information
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Benzoic Acid-Organocatalyzed Ring-Opening (co)Polymerization (ORO(c)P) of L-Lactide and Ɛ-Caprolactone Under Solvent-Free Conditions: from Simplicity to Recyclability.

Abstract The development of sustainable synthetic approaches to biodegradable and biocompatible polymeric materials represents a key challenge in polymer chemistry. A novel solvent-free and organocatalyzed ring-opening (co)polymerization (ORO(c)P) method utilizing benzoic acid (BA) as simple thermostable carboxylic acid-type catalyst is proposed to not only produce structurally well-defined aliphatic homopolyesters derived from L-lactide (L-LA) and Ɛ-caprolactone (CL), but also and, unexpectedly, statistical copolyesters based on the two monomer units. More information
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Influence of chain topology (cyclic versus linear) on the nucleation and isothermal crystallization of poly(L-lactide) and poly(D-lactide).

Abstract In this paper, ring closure click chemistry methods have been used to produce cyclic c-PLLA and c-PDLA of a number average molecular weight close to 10 kg/mol. Linear precursors (before ring closure) with similar molecular weights were employed for comparison purposes. The effects of stereochemistry of the polymer chains and their topology on their structure, nucleation and crystallization were studied in detail employing Wide Angle X-ray Scattering (WAXS), Small Angle X-ray Scattering (SAXS), Polarized Light Optical Microscopy (PLOM) and standard and advanced Differential Scanning Calorimetry (DSC).   More information
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Cyclic Polymers by the Ring-Closure Strategy: an Updated Review

Abstract The preparation of cyclic macromolecules has always represented a challenging task in polymer science mainly due to difficulties in connecting chain extremities together. Initiated with the pioneering works of Jacobson and Stockmayer, preparative pathways to cyclic polymers have been considerably improved within the last two decades thanks to the advent of both controlled polymerization mechanisms and efficient coupling reactions in organic chemistry. This review aims at providing a critical up-to-date overview and illustration of the considerable efforts that have been furnished in the past few years to improve the availability of macrocycles for industrial and academia investigations by means of
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Synthesis and characterization of double crystalline cyclic diblock copolymers of poly(e-caprolactone) and poly(L(D)-lactide) (c(PCL-b- PL(D)LA)).

Abstract The synthesis of symmetric cyclo poly(ε-caprolactone)–block–poly(L(D)-lactide) (c(PCL–b–PL(D)LA)) by combining ROP of ε-caprolactone and lactides and subsequent click chemistry reaction of the linear precursors containing antagonist functionalities is presented. The two blocks can sequentially crystallize and self-assemble into double crystalline spherulitic superstructures. The cyclic chain topology significantly affects both the nucleation and the crystallization of each constituent, as gathered from a comparison of the behavior of linear precursors and cyclic block copolymers. The stereochemistry of the PLA block does not have a significant effect on the non-isothermal crystallization of both linear and cyclo PCL-b-PDLA and PCL-b-PLLA copolymers.  More information
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