Suivi nanospectroscopique de la transformation de plastiques par recyclage chimique

Plastics are used in various domains and their production is constantly increasing, which consequently leads to an increase in plastic wastes. The origin of aged plastics is wide, used additives even wider, with high dilution level, which drastically complicate recycling process.
In the specific case of PET, high heterogeneities in terms of non / intentionally added substances (NIAS/IAS) exist in PET waste. When in forms of large micrometric particles like pigments, NIAS/IAS could be evidenced from macroscopic spectroscopic techniques like near and/or mid infrared microscopies (NIR, µIR) and removed by sorting or filtration after depolymerization. But part of NIAS/IAS are present in forms of organic molecules like dyes and are strongly diluted in the PET matrix which could alter the depolymerization process (by forming by-products) and may remain after depolymerization. In that case, rPET quality is reduced and cannot be used for medical and food packaging applications due to potential further NIAS/IAS migration. 
In the present work, we propose to develop methods based on emerging infrared nanospectroscopic techniques to detect small and diluted NIAS/IAS at different stages of PET recycling (virgin – aged – waste PET before/after glycolysis, BHET before/after purification).

Mots clés Recyclage plastique, spectroscopie vibrationnelle, AFM-IR, nanospectroscopie