Applied research rooted in industrial realities
It was during her training as a plastics engineer at INSA Strasbourg that Christelle Combeaud discovered her taste for applied research. Very early on, she became interested in scientific issues directly related to industrial needs, with a clear goal in mind: to understand plastics in order to use them more effectively.
As her research progressed, another dimension emerged: that of meaning. Giving meaning to her work by contributing to concrete solutions for society. This approach was consistent with her scientific commitment, which focused on a major challenge: plastic recycling.
Removing a major obstacle to plastic recycling
While recycling appears to be an essential solution to plastic pollution, it faces a major challenge: the variability of recycled polymers. Unlike standardized and homogeneous petroleum-based polymers, recycled plastics have highly variable mechanical and thermal properties, which complicates their industrial processing.
This variability has a direct impact on manufacturing processes such as extrusion, stretching, bottle blowing, and thermoforming, all of which require precise control of the physical and mechanical behavior of the material. Understanding, anticipating, and optimizing these mechanisms is at the heart of Christelle Combeaud’s research.
Observe matter undergoing transformation
Polymers, which are found in many plastics and elastomers, have a complex internal structure organized at the microscopic level. When heated or stretched, this local organization changes, altering their final properties, whether mechanical, thermal, optical, or barrier properties.
Christelle Combeaud’s research falls precisely within this pivotal area between:
- the physics of matter: how polymer macromolecular chains organize and structure themselves
- mechanics: how the material deforms depending on temperature and stretching speed
- and industrial processes: hollow body blowing, thermoforming, biaxial stretching, etc.
Its objective: to link microscopic phenomena to macroscopic behaviors observed at the scale of industrial objects.
Balanced bi-stretching of an amorphous PET, stretched at a temperature of 95°C and a strain rate of 1.4 s-1.
Stretching and developing microstructures: a material in motion
In her work, Christelle Combeaud studies in particular the stretchability of polymers above their glass transition temperature. At this critical temperature, an amorphous polymer changes from a brittle/glass-like state to a ductile/rubbery state, which allows it to be shaped.
By subjecting these polymers to controlled stretching, she shows that:
- their internal structure reorganizes itself
- specific microstructures appear and become textured
- and these transformations directly influence their mechanical, thermal, and barrier properties
By studying the links between temperature, deformation path, and internal organization of matter, it sheds light on fundamental mechanisms while addressing very concrete issues of production and durability of deformed polymer materials.
Longitudinal deformation fields of a recycled PET preform, blown at 107°C.
From the laboratory to the factory: science serving society
To meet these challenges, the researcher is conducting numerous projects in partnership with the plastics industry. Her current goal is to help them better understand the influence of incorporating recycled plastic into virgin reference materials and to adapt their production processes to these new materials.
She is currently leading the CYCLADES industrial chair project at CEMEF, in collaboration with IPC (Industrial Technical Center for Plastics and Composites). The objectives of this chair are to understand the influence of incorporating recycled raw materials (RRM) on the behavior of polymer or composite materials in various fields of application (automotive, aeronautics, packaging, construction, etc.). The scientific strategy adopted is to link the shaping process, microstructure developments, and final properties in order to optimize shaping processes. This initiative paves the way for new collaborations between academic and industrial research, which are essential for accelerating the transition to a circular economy.
A diverse and committed scientific career
