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Portail > Offres > Offre UMR5521-LAUORG-006 - Offre de Postdoc - Micromécanique et imagerie 3D de nouveaux papiers et cartons à hautes propriétés mécaniques (H/F)

Postdoc position - 3D imaging and micromechanics of novel strengthened papers and paperboards (H/F)

This offer is available in the following languages:
Français - Anglais

Date Limite Candidature : mardi 12 juillet 2022

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General information

Reference : UMR5521-LAUORG-006
Workplace : GRENOBLE
Date of publication : Tuesday, June 21, 2022
Type of Contract : FTC Scientist
Contract Period : 12 months
Expected date of employment : 1 September 2022
Proportion of work : Full time
Remuneration : from 2663.79 € per month, depending on the professional experience
Desired level of education : PhD
Experience required : 1 to 4 years

Missions

Designing renewable and biodegradable materials for, e.g., food or health packaging is of major importance. Many research efforts are being developed purposely, in particular by looking for novel processing routes with ligno-cellulosic fibers extracted from the vegetal biomass to produce novel papers and paperboards with enhanced thermo-hygro-mechanical properties. In particular, this challenging objective require the improvement of fiber-fiber links to reinforce the mechanical properties of fibrous networks, by optimizing the density and/or the quality of nanoscale chemo-physical bonds (hydrogen, electrostatic…) between fibers. Several strategies are known for that purpose. For example, fiber refining to produce “forests” of cellulose microfibrils around fibers that increase the connections between fibers during paper making operations is a well-known and efficient solution. However, it is energy consuming since it requires substantial effort to extract water from the fibrous network during paper pressing. Here, we wish to explore another strategy, less energy consuming, by improving the morphology, and thus the mechanical properties of usual fiber bonds.

This is the main objective of the “FibreFlex” project. Papers and paperboards will be manufactured using fibers the morphology of which will be optimized with chemo-mechanical pre-treatments. The role of the postdoc will consist in characterizing (i) the 3D fibrous structures of the processed papers with a special focus on the density and the geometry of fiber-fiber bonds, (ii) the micromechanics of individual fiber-fiber bonds, (iii) the macroscopic hygro-mechanical properties of papers, and (iv) in proposing a micromechanical approach to model their macroscopic mechanical behavior.

Activities

For that purpose, various experimental/numerical analyses will be carried out:
- Mechanical tests with various mechanical loadings (uniaxial, plane strain tensile tests), controlled environment (temperature, relative humidity) and kinematical field measurements (SDIC),
- Micromechanical tests on fiber-fiber bonds
- 3D imaging using X-ray nano-tomography and dedicated image analysis to extract relevant descriptors of fiber and fiber-bonds.
- A discrete element code will be improved and used to mimic the macroscopic mechanical properties from the knowledge of the fibrous microstructure and micromechanics

Skills

- PhD in mechanics of materials or materials science
- Keywords : Bio-based materials, experimental mechanics, 2D/3D imaging for heterogeneous/fibrous materials, discrete simulation

Work Context

- The proposed offer is part of the Carnot Insitute Polynat (http://www.celluwiz.eu/) project FibreFlex which includes two research units of the Centre National de la Recherche Scientifique (CNRS), the biggest french research institute, and one industrial partner, Centre Technique du Papier (CTP).
- Location: the postdoc project will be located in the ComHet research group (Mechanics and Multiphysics Coupling in Heterogeneous Materials) of the 3SR Lab, a Solids Mechanics research unit of the CNRS and the Univ. Grenoble Alpes (Grenoble, France, https://3sr.univ-grenoble-alpes.fr/), with strong interactions with the projects partners, LGP2 and CTP.

Constraints and risks

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Additional Information

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