2025-10-10 ジョージア工科大学 (Georgia Tech)
The high impact between the metal balls in a ball mill reactor and the polymer surface is sufficient to momentarily liquefy the polymer and facilitate chemical reactions.
＜関連情報＞
- https://research.gatech.edu/new-method-uses-collisions-break-down-plastic-sustainable-recycling
- https://www.sciencedirect.com/science/article/abs/pii/S2451929425003456
ポリマーのメカノケミカルアップサイクリングにおける空間分解反応環境 Spatially resolved reaction environments in mechanochemical upcycling of polymers
Kinga Gołąbek, Yuchen Chang, Lauren R. Mellinger, Mariana V. Rodrigues, Cauê de Souza Coutinho Nogueira, Fabio B. Passos, Yutao Xing, Aline Ribeiro Passos, Mohammed H. Saffarini, Austin B. Isner, David S. Sholl, Carsten Sievers
Chem Available online: 6 October 2025
DOI:https://doi.org/10.1016/j.chempr.2025.102754
Highlights
- PET depolymerizes by reacting with NaOH under sufficiently strong mechanical impact
- Crater morphology reveals zones of elastic and plastic deformation
- Amorphization enhances accessibility of ester bonds for alkali depolymerization
- Multiscale analysis enables kinetic modeling of mechanochemical processes
The bigger picture
Mechanochemical processes offer a promising approach to integrating solid feedstocks, such as waste plastics and biomass, into chemical plants. The complexity of reaction environments in ball mills has hindered predictive reactor design. Although recent studies highlight the potential of mechanochemistry, they focus on lab-scale reactions without addressing scalability. This work bridges this gap by exploring polymer upcycling through a combined approach: simulations with a material point method model and spatially resolved spectro-microscopic characterization of a single collision. This provides a fundamental understanding of mechanochemical reaction kinetics and enables bottom-up modeling of these processes across different scales.
Summary
Mechanochemical processing is an attractive and scalable approach for the upcycling of polymers. The complex and dynamic environment in ball milling, however, makes gaining insight into the physicochemical nature of the collisions driving mechanochemistry challenging, which, in turn, hampers the optimization of these processes. We used controlled single impacts followed by multiple spatially resolved analytical methods (focused ion beam microscopy, Raman spectro-microscopy, and small-angle X-ray scattering) and material point method simulations to gain unprecedented information about mechanochemical depolymerization of poly(ethylene terephthalate). These measurements highlight the contributions of plastic deformation, amorphization, and depolymerization during the transfer of kinetic energy in collisions relevant to ball mills and will enable reactor models based on fundamental kinetics.
