Spectral methods for online monitoring of polyolefin recycling processes by dissolution-precipitation

Plastics, which appeared more than a century ago, have gradually established themselves in a multitude of applications thanks to their interesting properties and their low cost. Nevertheless, their fate at the end of their life has become a major environmental and societal concern, and despite continuous developments in mechanical recycling, succeeding in recycling all plastic material remains a global challenge and is the subject of intense research efforts.
One promising technology is chemical recycling of polyolefins by dissolution-precipitation. This solution is applicable to a wide spectrum of plastic materials because it makes it possible to eliminate the various additives present in the polymer matrix and thus to obtain a virgin resin. However, as developing these processes requires a substantial experimental program, innovative in situ characterizations have to be implemented in order to be efficient.
To achieve this, online analysis tools such as Raman, mid-infrared, near-infrared, and UV-visible spectroscopy appear to be suitable candidates because they are fast, non-destructive, sensitive to chemical and physical properties, and easy to implement online. The PhD student’s challenge will  be to construct an appropriate database and to develop chemometric models to determine the desired properties (nature, size, concentration of the macromolecules, as well as concentration of some targeted additives) from the online measurements. He/she will then apply this method to the case of the kinetic study of the dissolution and precipitation steps of a polyolefins purification process.
This thesis will mainly take place at CP2M in Lyon, and occasionally at IFP Energies Nouvelles on its Solaize site.

Keywords: polyolefin dissolution, vibrational spectroscopy, in-line analysis, plastic recycling

• Academic supervisor    PhD, MONTEIL Vincent, CNRS Research Director / Team Polymerization Catalysis Materials – CP2M Laboratory, https://orcid.org/0000-0003-3530-1789
• Doctoral School    ED 206, Ecole doctorale de chimie de Lyon, https://www.edchimie-lyon.fr/
• IFPEN supervisor    PhD, REY-BAYLE Maud, online analysis research engineer, pilot engineering, maud.rey-bayle@ifpen.fr https://orcid.org/0000-0002-4686-1178
• PhD location    Laboratoire polymérisation catalyse et matériaux, Villeurbanne, France  
• Duration and start date    3 years, starting in November 2022
• Employer    IFP Energies Nouvelles, Solaize, France
• Academic requirements    University Master degree polymer or analytic sciences
• Language requirements    Fluency in French and English
• Other requirements    Knowledge of statistics and chemometrics appreciated, sensitivity to chemical engineering