ESPCI web site
ESPCI Paris
Lieu de travail
Paris - Ile-de-France - France
Intitulé du sujet
Design, synthesis, characterization and processing of innovative vitrimers
Champs scientifiques
Chimie
Description
Due to their remarkable mechanic properties and robustness, thermosets are ubiquitous materials used in a myriad of applications. However, their permanent tridimensional molecular structure makes them difficult to process, reshape or recycle. Given the massive use of these materials worldwide, these limitations pose important economical and environmental issues. On the contrary, thermoplastics are easy to process but suffer from their moderate mechanical properties, weak chemical resistance and poor dimensional stability at high temperature. Thus, a polymer combining the superior properties of thermosets with the processability and recyclability of thermoplastics is very attractive. Such materials have been developed upon the introduction of exchangeable covalent bonds within the polymer network. In 2011, the concept of vitrimers was introduced by Ludwik Leibler and his team : vitrimers behave as thermosets at service temperature but can be reshaped or recycled once heated. The exchangeable links present in vitrimers play a crucial role, they provide strength akin to thermosets at operating temperature but allow for remolding at elevated temperature. They must be chemically and thermally robust, so they do not induce side reactions or undergo degradation during material processing at high temperature. In addition, it is essential that exchange reactions are slow or can be completely blocked at service temperature, for vitrimer to truly behave like thermosets, while being extremely rapid at elevated temperatures, to allow easy processing. Finding an exchange reaction that combines all these characteristics would allow vitrimers to completely fulfill their tremendous potential, but has yet to be done. In that context, the objective of this PhD is the identification and development of such a dynamic reaction, and its implementation into vitrimers. A special effort will be made to develop approaches and molecules that are non-expensive, which syntheses can be easily scaled up, and as much as possible biobased. In addition, a special focus will be dedicated to the develop vitrimers from the most important industrial polymers, such as polystyrene, polyethylene, polyethylene terephthalate, poly(methyl methacrylate). To meet these goals, the project will rely on the expertise of Dr. Amandine Guérinot in the development of innovative methods for the synthesis of functionalized small molecules, as well as on the expertise of Dr. Renaud Nicolaÿ on macromolecular engineering and vitrimers. The PhD project will encompass several steps from the study of dynamic reactions using small molecules (kinetics, activation energy, mechanism) to the design, synthesis and characterization (mechanical/rheological properties) of original vitrimers. The processing by extrusion molding will be studied as well as the recyclability of the polymer.
3i Aspects
Intersectoriality will be at the heart of this project whose final objective is to design, prepare and characterize industrially relevant materials. Vitrimers have already raised a tremendous interest from industry, from sectors as different as cable insulation, water piping, 3-D printing, packaging, textiles, tires, transportation and energy. The project will benefit from the strong industrial network established by the MMC team around vitrimer conception. The project is fundamentally based on an interdisciplinary approach combining molecular chemistry, macromolecular chemistry and material engineering. Studies will include controlling and adjusting the dynamic of exchange of chemical bonds, both on model molecules and within polymer matrices, the design of monomers and reactive additives that will be used to prepare new vitrimers, and the characterization of the macroscopic behavior of vitrimers , e.g. their processability, physico-chemical and mechanical properties, and recyclability. This project will therefore provide to the student a multidisciplinar formation in chemistry, ranging from fundamental studies to material characterization and processing, which will be undoubtedly a unique asset for his/her future career. The field of vitrimer is a young but already internationally recognized axis of research, both in academia and industry. As a world leader in vitrimer conception and characterization, ESPCI Paris possesses unique opportunities for international collaborations. The project could benefit from these interactions with laboratories based in USA and Europe.
PhD supervisor(s) Amandine Guérinot and Renaud Nicolay (co-supervisor)
Présentation établissement et labo d’accueil
ESPCI Paris
The Hosting Lab
A. Guérinot currently belongs to the “Laboratory of Organic Chemistry” (Chemistry, Biology, Innovation unit, UMR 8231), while R. Nicolaÿ works in the “Soft Matter and Chemistry” unit (UMR 7167). In 2019, these two teams will merge to form a new research unit called “Molecular, Macromolecular and Materials Chemistry”. The unit will be divided in 3 teams : “Molecular Chemistry and Catalysis”, “Macromolecular Design and Chemistry” and “Formulation Chemistry and Physical-chemistry”. The ambition of this unit is to develop an integrated approach from the molecular level to materials processing by taking advantage of the complementary expertise of the different members. These synergic interactions will be exploited through 3 main interdisciplinary research axes, which are nanocatalysis, complex macromolecular systems and vitrimer materials. Thus, the present PhD project perfectly fits in this scientific program. It will be a mean to build momentum between the teams of the new research unit since the very beginning of its existence. It will be a starting point for further fruitful collaborations within the research unit and thus encourage the emergence of novel research areas.
Site web :
https://www.upto.paris/
Profil du candidat
The PhD candidate should possess a strong formation in organic chemistry and polymer chemistry. The present project covers several areas of chemistry and material science, including fundamental studies, synthesis, characterization (chemical, physico-chemical and mechanical) and processing. Thus the candidate should be adaptable, curious and opened to this kind of multidisciplinary project. Strong skills and interest in experimental work will be required. A multidisciplinary formation in chemistry and physics would be a real advantage.
Date limite de candidature
28/02/2018
Date de début de thèse
01/09/2018
Eléments à fournir pour la candidature
Applications must be submitted on the UPtoPARIS
More information is available in the "How to apply" section of the website.