Missions

-------- MISSION --------
Duration of 12 months renweable once. Research work focused on the development of ex-cellulose carbon fibers will be conducted in two main areas. The first will involve developing carbon fibers by pyrolysis of cellulose precursor threads produced by the CANOE platform, in ionic liquid media and using several versions of a raw material supplied by an industrial manufacturer. The second will consist in characterizing these same fibers at different stages of their transformation, both to better interpret the final results obtained on the carbon fibers and to ensure a thorough understanding of the reaction mechanisms involved, which necessarily determine the final properties.
The first area will involve optimizing the continuous pyrolysis process, consisting in a line of furnaces fed by an automated conveyor system. Its target will be a set of properties expected and specified by manufacturers. It will be based on a physico-chemical and thermal characterization of the proposed precursors, the interpretation of which will aim at ipre adjusting the process parameters.
The second area, which consists in determining the performance of the carbon fibers obtained, will draw on a wide range of chemical, physico-chemical, and thermomechanical methods and expertise. Establishing the classic links in materials science between the manufacturing process, microstructure, and properties will obviously be at the heart of the approach, as this remains a major scientific challenge given the complexity of the chemical transformations involved.

The postdoctoral researcher will therefore be tasked with working closely with CEA engineers and LCTS researchers to propose:
• methodologies for conducting experiments,
• characterization strategies, and, of course, interpretations of the results.
Regular reports will be produced, which should enable one or more publications to be written.

Activités

-------- MAIN ACTIVITY--------
The researcher (M/F) will operate, maintain, and, if necessary, improve an existing pyrolysis system consisting in thermal treatment furnaces and an automated scrolling system.
In addition, the researcher (M/F) will perform characterizations to determine the properties of the fibers obtained. Static pyrolysis furnaces, automated continuous pyrolysis line, ATG coupled with FTIR, DSC, ATM, BET, thermo-mechanical characterization bench on monofilament (tension), Raman spectroscopy, SEM, TEM comprise the range of equipment and technologies that will be used.

Compétences

-------- SKILLS --------
A PhD holder, initial professional experience would be an advantage.
The candidate (M/F) must have in-depth knowledge in chemistry and in physics. Independent, enjoying experimentation and teamwork, the candidate must be able to carry out development and characterization work, as well as analyze and synthesize results.

Contexte de travail

-------- CONTEXT --------
Carbon fibers are the reinforcement of choice for most applications that require a combination of lightness and mechanical performance. Depending on the application, the properties sought may vary (rigidity, mechanical strength, thermal conductivity, etc.). The characteristics of carbon fibers result from the close combination of perfect control over the manufacture of a polymer precursor filament (product chemistry and spinning) and precise control over its transformation into carbon.
Cellulose, which led to the discovery of carbon fibers, continues to be the benchmark precursor for obtaining fibers with low thermal conductivity. These fibers are preferred for reinforcing carbon/resin composites, which are used to provide thermal protection for vehicles re-entering the atmosphere.
New concepts for developing these precursors are currently being studied to replace conventional processes, which are relatively polluting and costly. Spinning in ionic liquid media is a promising alternative method whose TRL readiness level is worth being adressed. In addition, cellulose, which has been largely abandoned in favor of the precursor polyacrylonitrile in the synthesis of mechanically high-performance fibers, is now enjoying renewed interest as the most abundant bio-based polymer on the planet. Numerous research projects are emerging.
In this context, the Nouvelle Aquitaine region benefits from a particularly relevant ecosystem: a well-established paper industry, the presence of cutting-edge research and development entities in the field of composites, particularly fiber reinforcements (LCTS, CANOE platform), and finally, space industry leaders (CEA, Ariane Group) at the European level in their sector of activity.
The studies planned at LCTS in this field are therefore part of this context.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

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Informations complémentaires

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