Description du sujet de thèse

With an annual production estimated at more than 600,000 tonnes and a rapidly growing market, galvanized by increasingly worrying societal and environmental issues, polymer foams are omnipresent in our daily lives because they respond to a need for lighter structures associated with a low thermal or electrical conductivity. Considering this industrial and economic potential, the design of more efficient and degradable polymer foams, as well as the development of new methods of manufacturing these more efficient and virtuous foams are at the heart of the GreenFoam project (PEPR DIADEM) in which is part this thesis.
Compared to conventional materials, foams bring a new dimension: they are structured according to more or less complex, periodic or random three-dimensional arrangements. The design field of these materials encompasses a considerable number of combinations which makes it difficult to understand the search for an optimal design, whether via experimental measurements or numerical simulations. In particular, the complex and sometimes stochastic structure of foams makes it difficult to develop constitutive models for these architectural materials. Thus, the objective is to implement a scientific approach combining rationalized, high-throughput experimentation, digital simulation and artificial intelligence to accelerate the discovery of more eco-responsible high-performance foams.
The GreenFOAM project, for the accelerated discovery and optimization of high-performance, eco-responsible foams with hierarchical architectures via photo-induced processes, was selected as part of the PEPR DIADEM dedicated to the accelerated development of emerging materials assisted by AI.
As part of this project, you will join the MIM team at ICS, UPR 22 CNRS.
Your work will consist of:
1. Develop a digital tool to reproduce the foaming process of a polymer mixture based on physical parameters derived from the process. In particular, the interaction between crosslinking or solidification reactions and the kinetics of cell swelling plays an essential role in foam formation. For this task, the candidate will rely on an “ad-hoc” model previously developed at the ICS and capable of producing representative volumes of foam from a thermodynamic description of the growth of a set of gas bubbles. in a polymer in the molten state.To correlate the models with the experiment, the characterization and monitoring of the foaming process will be carried out by X-ray microtomography, available at the ICS. One of the objectives of this multi-physics modeling concerns the optimization of parameters in order to structure a cellular organization according to a specific morphology.
2. Interpret the link between cell morphology and mechanical properties. In this context, a micromechanical approach will be adopted to establish behavior models based on finite element (FE) analysis. This aspect will be combined with analytical models that are more easily modulated from a set of microstructural parameters. The results will be used to construct a more complete model of “ad hoc” mechanical behavior, including variations inherent to cell organization.
the candidate (M/F) will also work in close collaboration with the experimental team (IS2M, UMR 7361/LCPO, UMR 5629) dedicated to the development of green foam chemistry and with the CSIP team from the ICube laboratory (UMR7357) for the related modeling part. with AI to promote creativity and overcome design barriers of architectural materials, such as foams.
SKILLS :
Candidates must hold an engineering degree/Master 2 or equivalent in mechanics/materials science, with a strong interest in digital modeling and data analysis. Knowledge of programming languages ​​(Matlab, Python, Fortran) will be appreciated. This thesis work will rely on the skills of several teams including chemists, physicists and mechanics. The candidate must therefore show a certain ability to aggregate a set of information from different fields.

Contexte de travail

The thesis is attached to the doctoral school of physics and physical chemistry (ED182) in Strasbourg.. The Charles Sadron Institute (ICS) is a CNRS research unit located on the Cronenbourg campus. This multidisciplinary institute dedicated to polymer materials and self-assembled systems employs around 190 people, half of whom are non-permanent. The ICS is organized into 7 research teams, 4 technological platforms and administrative and technical services. The recruited person will be assigned to the MIM (Mechanics of Interfaces and Multiphase Systems) team.

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

No constraint or risk