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To fully capitalize on the unique properties of 2D materials, cost-effective techniques for producing high-quality 2D flakes at scale are crucial. In this work, we show that dry ball-milling, a commonly used powder-processing technique, can be effectively and efficiently upgraded into an automated exfoliation technique. It is done by adding polymer as adhesives into a ball mill to mimic the well-known tape exfoliation process, which is known to produce 2D flakes with the highest quality but is limited by its extremely low efficiency on large-scale production. Seventeen types of commonly seen polymers, including both artificial and natural ones, have been examined as additives to dry ball-mill hexagonal boron nitride. A parallel comparison between different additives identifies low-cost natural polymers such as starch as promising dry ball-mill additives to produce ultrathin flakes with the largest aspect ratio. The mechanical, thermal, and surface properties of the polymers are proposed as key features that simultaneously determine the exfoliation efficiency, and their ranking of importance in the mechanical exfoliation process is revealed using a machine learning model. Finally, the potential of the polymer-assisted ball-mill exfoliation method as a universal way to produce ultra-thin 2D nanosheets is also demonstrated.
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Discrete Element Simulation and Economics of Mechanochemical Grinding of Plastic Waste at an Industrial Scale
Efficient and sustainable chemical recycling pathways for plastics are vital for addressing the negative environmental impacts associated with their end-of-life management. Mechanochemical depolymerization in ball mill reactors is a new promising route to achieve solid-state conversion of polymers to monomers, without the need for additional solvents. Physics-based models that accurately describe the reactor system are necessary for process design, scaling up, and reducing energy consumption. Motivated by this, a Discrete Element Method (DEM) model is developed to investigate the ball milling process at laboratory and industrial scales. The lab-scale model is calibrated and validated with data extracted from videos using computer vision tools. Finally, scaled-up ball mill designs capable of depolymerizing varying feeds of PET waste were simulated, and their capital and operating costs are estimated to assess the economic potential of this route.
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- Award ID(s):
- 2028998
- PAR ID:
- 10471326
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Computer aided chemical engineering
- ISSN:
- 2543-1331
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
