Structure-Property Relationships of Recycled PVC

Polyvinyl chloride called PVC is the third most produced synthetic polymer in the world. This economic success is explained not only by its low production cost, the excellence of its properties but also by its versatility. This omnipresence results in the abundant generation of waste, the burial and incineration of which remain problematic. This observation shows the interest of a PVC recycling strategy as part of the energy transition. Furthermore, given the evolution of the REACH regulations in Europe, phthalates used in the formulation of PVC are harmful and will be prohibited, hence the need to develop alternative recycling routes which will make it possible to extract the additives initially present in the formulation while maintaining the characteristics of the polymer chains. Among the possible PVC recycling technologies, IFPEN is interested in the chemical route based on deformulation followed by reformulation. This thesis aims at ensuring that the different stages of the recycling process do not alter the final properties of the material. Thus, it is necessary to better understand the polymer-solvent interactions occurring during the deformulation step. The isolated chains will be further reformulated with reference additives to ensure the processability of the new formulation and the maintenance of the properties of use. For this, two areas of study will be followed:
- the rheological characterization of macromolecules in solution, and in the molten state
- the impact of mechanical degradation on dehydrochlorination associated with the study of the thermal stability of the polymer.
Model PVCs will be initially studied to develop methodologies which will then be applied to a post-consumer flexible PVC. These analyzes will allow to understand the appearance of possible degradations undergone by the macromolecules. Furthermore, it is important to qualify the usage properties obtained after these recycling steps. This thesis will also make it possible to broaden skills in materials - processes and rheology at different scales, but also and above all to improve the understanding of PVC recycling.

Keywords: PVC recycling, rheology, processing

• Academic supervisor    Pr, LAMNAWAR Khalid Département Génie Mécanique-INSA Lyon 0000 0003 49070977 ORCID
• Doctoral School    Ecole Doctorale Matériaux de Lyon, https://ed34.universite-lyon.fr/
• IFPEN supervisor    Dr, HENAUT Isabelle, Physico-chimie des interfaces et fluides complexes,  isabelle.henaut@ifpen.fr, 0000-0003-1923-0706 ORCID
• PhD location    IFP Energies nouvelles, Rueil-Malmaison, France   
• Duration and start date    3 years, starting in fourth quarter 2023
• Employer    IFP Energies nouvelles, Rueil-Malmaison, France   
• Academic requirements    University Master degree in physical chemistry, soft matter
• Language requirements    Fluency in French or English, willingness to learn French