Year: 2025
Type: article
Abstract: Synthetic plastics sourced from petroleum have gained widespread use since the 1950s. Polystyrene (PS) is one of the most extensively used plastics, as it is colorless, has high mechanical strength, and exhibits excellent chemical and thermal stability; however, it is also one of the least recycled plastics because of the high cost and low profit in recycling. Herein, we demonstrate a mechanochemical recycling approach that allows PS to be efficiently degraded into benzene when it is ground in a ball mill with AlCl3. For example, when 165 kDa PS pellets are milled with AlCl3, the extent of degradation reaches 90% at 15 min. Isotope labeling experiments indicate that both ambient water and the polymer backbone can be proton sources for the formation of benzene. The benzene generated in the mechanochemical degradation can be used to synthesize styrene, which can be repolymerized to produce polystyrene, allowing for the closed‐loop recycling of PS. In addition, a mechanochemical Friedel–Crafts acylation between the generated benzene and the subsequently added benzoic anhydride produces benzophenone in 40%–50% yield. The mechanochemical degradation process demonstrated here is solvent‐free, cost‐effective, and energy‐efficient, providing a promising route for the chemical recycling and upcycling of PS.
Authors: Ming‐Chi Wang, Junyang Li, Ashley Zelina, Benjamin Pepper, Junpeng Wang
Institution: University of Akron
Language: English
Subfield: Polymers and Plastics
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,510
Awards: CAS-Climate: Mechanically Active Degradable Polymers, G5269062458, G5546407176, REU Site: Polymer Science and Engineering at The University of Akron, G6807129519, MRI: Acquisition of a MALDI‐ToF Mass Spectrometer to Advance Research and Education in Polymer Science and Engineering, G7693907948, G8507380447
OpenAlex ID: W4413605166