Catégories
macromolecular

Cyclic polymers: Advances in their synthesis, properties, and biomedical applications.

Cyclic polymers: Advances in their synthesis, properties, and biomedical applications.

Romain Liénard, Julien De Winter, Olivier Coulembier

Abstract :  This review aims to give an overview on the recent progresses in the field of ring polymers to this day. The current state of the art of the preparation of cyclic polymers, the challenges related to it such as the purification of the samples and the scalability of the synthetic processes, the properties arising from the cyclic topology and the potential use of cyclobased polymers for biomedical applications are as many topics covered in this review.

Catégories
macromolecular

Selective Organocatalytic Preparation of Trimethylene Carbonate from Oxetane and Carbon Dioxide.

Selective Organocatalytic Preparation of Trimethylene Carbonate from Oxetane and Carbon Dioxide.

Jin Huang, Coralie Jehanno, Joshua C. Worch, Fernando Ruipérez, Haritz Sardon, Andrew P. Dove*, and Olivier Coulembier*

Abstract :  The organocatalytic coupling of oxetanes and carbon dioxide (CO2) offers a sustainable route to poly(trimethylene carbonate)s and/or functional 6-membered cyclic carbonate monomers. This transformation is more challenging than when using more strained epoxide comonomers and even more so when it is performed using sustainable metal-free routes. Herein, we report a mild, organocatalytic oxetane/CO2 coupling procedure that enables the selection of cyclic carbonate or polymer from a common intermediate. Using a novel I2-based binary catalyst system, cyclic carbonate with high selectivity (up to 94%) was obtained at 55 °C whereas simply changing the temperature to 105 °C yielded the polycarbonate with Mn up to 6.4 kDa thus showing that either trimethylene carbonate or its concomitant polycarbonate product can be selected solely by manipulation of the reaction conditions.

Catégories
macromolecular

Update and Challenges in Carbon Dioxide-Based Polycarbonate Synthesis.

Update and Challenges in Carbon Dioxide-Based Polycarbonate Synthesis.

Dr. Jin Huang, Dr. Joshua C. Worch, Prof. Dr. Andrew P. Dove, Prof. Dr. Olivier Coulembier

Abstract : The utilization of carbon dioxide as a comonomer to produce polycarbonates has attracted a great deal of attention from both industrial and academic communities because it promises to replace petroleum-derived plastics and supports a sustainable environment. Significant progress in the copolymerization of cyclic ethers (e.g., epoxide, oxetane) and carbon dioxide has been made in recent decades, owing to the rapid development of catalysts. In this Review, the focus is to summarize and discuss recent advances in the development of homogeneous catalysts, including metal- and organo-based complexes, as well as the preparation of carbon dioxide-based block copolymer and functional polycarbonates.

Catégories
macromolecular

Simultaneous “O−Alkyl” and “O−Acyl” Lactone Cleavages from Hydroxy-Carboxylic Acid Initiators: Direct Access to Multiblock Architecture

Simultaneous “O−Alkyl” and “O−Acyl” Lactone Cleavages from Hydroxy-Carboxylic Acid Initiators: Direct Access to Multiblock Architecture

Bryan Raeskinet, Sébastien Moins, Luke Harvey, Julien De Winter, Céline Henoumont, Sophie Laurent, and Olivier Coulembier

Abstract : Herein, we demonstrate the possibility to prepare multiblock polyester-based copolymers in a “one-pot, one-step” approach from independent and simultaneous ROPs of 4- and 6-membered lactones. The independent behavior of those polymerizations appears to be possible due to the ability of 4- and 6-membered lactones to polymerize selectively by “O−alkyl” and “O−acyl” cleavages, respectively. Those two types of lactone bond ruptures have been initiated from various heterofunctional moieties bearing hydroxyl and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-based carboxylic salt functions.

Catégories
macromolecular

Metal-free Synthesis of Poly(trimethylene carbonate) by Efficient Valorization of Carbon Dioxide.

Metal-free Synthesis of Poly(trimethylene carbonate) by Efficient Valorization of Carbon Dioxide.

Jin Huang, Julien De Winter, Andrew P. Dove and Olivier Coulembier

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.