Description du sujet de thèse

In the field of materials science and engineering, polymers play a crucial role due to their wide range of applications. However, in light of growing environmental concerns, there is an urgent need to develop more sustainable polymer materials. While thermoplastics offer recyclability and reshaping capabilities, they often lack the mechanical performance required for demanding applications. On the other hand, thermosets provide superior mechanical properties but are neither recyclable nor reusable, raising increasing concerns about waste generation.
To address this dilemma, a new class of polymer materials known as Covalent Adaptable Networks (CANs) has recently been developed. These materials bridge the gap between thermosets and thermoplastics by offering both crosslinked structures and recyclability. CANs rely on reversible covalent bonds, primarily involving bond exchange reactions such as ester-alcohol (transesterification) or amine-imine (transamination) mechanisms.
Recently, a new bond exchange reaction was discovered in our research group, opening up exciting opportunities to develop and study an entirely new family of CANs. In this project, we propose to explore this novel class of materials through the synthesis of CAN-building monomers and their subsequent use in polymer formation. We will also investigate the underlying exchange mechanisms and the mechanical properties of the resulting CANs.
In the first part of the project, the monomers used to form the CANs will be synthesized and employed both in polymer network formation and in model reactions. These model systems will allow us to study, in detail and at the molecular level, the dynamics of the exchange mechanisms. This foundational understanding will then guide the design of a second generation of monomers, bearing diverse chemical functionalities, to fine-tune the steric and electronic environments near the reactive sites. The goal is to modulate and control the exchange reactions in order to influence the material properties.
The second part of the project will focus on studying the mechanical and thermo-mechanical properties of the CANs and correlating the results with the model exchange studies. This will enable us to better understand — and ultimately predict — the behavior of these materials as a function of the monomers used.
Finally, we will assess the recyclability and reprocessability of these newly developed CANs to gain a complete understanding of their potential — from monomer synthesis to end-of-life recycling.
The PhD candidate will work at Softmat Laboratory (UMR CNRS 5623), located on the University of Toulouse III – Paul Sabatier campus. The laboratory's research activities cover the study of self-organized molecular and macromolecular systems, spanning from the synthesis of building blocks to their physico-chemical characterization and potential applications. The PhD student will be part of the P3R team, which has strong expertise in polymer chemistry, degradable polymers, and dynamic covalent materials such as Covalent Adaptable Networks (CANs) and vitrimers.

Contexte de travail

The PhD will take place within the SOFTMAT Laboratory (Chemistry of colloids, polymers, and complex assemblies), a joint research unit (UMR CNRS 5623) affiliated with the University of Toulouse. The laboratory is organized into four research teams, covering interdisciplinary topics in polymer chemistry, colloid physico-chemistry, self-assembly, and bio-inspired chemistry.
The PhD project will be conducted within the P3R team (Precision Polymers by Radical Processes), which has strong expertise in the development of innovative polymer materials through controlled radical polymerization. One of the key research areas of the team focuses on dynamic polymer materials, particularly vitrimers, which combine mechanical robustness with the ability to be reshaped or recycled thanks to dynamic covalent bond exchange reactions.
The thesis will be co-supervised by Olivier Coutelier (Associate Professor) and Marc Guerre (CNRS Research Scientist). This PhD project is part of the ANR-funded project THIODYNMAT, which aims to develop and characterize new classes of covalent adaptable materials based on thiolactone chemistry.