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Parkatzidis K, Wang HS, Anastasaki A. Photocatalytic Upcycling and Depolymerization of Vinyl Polymers. Angew Chem Int Ed Engl 2024; 63:e202402436. [PMID: 38466624 DOI: 10.1002/anie.202402436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/10/2024] [Accepted: 03/11/2024] [Indexed: 03/13/2024]
Abstract
Photocatalytic upcycling and depolymerization of vinyl polymers have emerged as promising strategies to combat plastic pollution and promote a circular economy. This mini review critically summarizes current developments in the upcycling and degradation of vinyl polymers including polystyrene and poly(meth)acrylates. Of these material classes, polymethacrylates possess the unique possibility to undergo a photocatalytic depolymerization back to monomer under thermodynamically favourable conditions, thus presenting significant advantages over traditional thermal strategies. Our perspective on current formidable challenges and potential future directions are also discussed.
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Affiliation(s)
- Kostas Parkatzidis
- Department of Materials Science, ETH Zurich, Vladimir-Prelog-Weg 5, 8093, Zürich, Switzerland
| | - Hyun Suk Wang
- Department of Materials Science, ETH Zurich, Vladimir-Prelog-Weg 5, 8093, Zürich, Switzerland
| | - Athina Anastasaki
- Department of Materials Science, ETH Zurich, Vladimir-Prelog-Weg 5, 8093, Zürich, Switzerland
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Wimberger L, Ng G, Boyer C. Light-driven polymer recycling to monomers and small molecules. Nat Commun 2024; 15:2510. [PMID: 38509090 PMCID: PMC10954676 DOI: 10.1038/s41467-024-46656-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/05/2024] [Indexed: 03/22/2024] Open
Abstract
Only a small proportion of global plastic waste is recycled, of which most is mechanically recycled into lower quality materials. The alternative, chemical recycling, enables renewed production of pristine materials, but generally comes at a high energy cost, particularly for processes like pyrolysis. This review focuses on light-driven approaches for chemically recycling and upcycling plastic waste, with emphasis on reduced energy consumption and selective transformations not achievable with heat-driven methods. We focus on challenging to recycle backbone structures composed of mainly C‒C bonds, which lack functional groups i.e., esters or amides, that facilitate chemical recycling e.g., by solvolysis. We discuss the use of light, either in conjunction with heat to drive depolymerization to monomers or via photocatalysis to transform polymers into valuable small molecules. The structural prerequisites for these approaches are outlined, highlighting their advantages as well as limitations. We conclude with an outlook, addressing key challenges, opportunities, and provide guidelines for future photocatalyst (PC) development.
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Affiliation(s)
- Laura Wimberger
- Cluster for Advanced Macromolecular Design and School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
| | - Gervase Ng
- Cluster for Advanced Macromolecular Design and School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
| | - Cyrille Boyer
- Cluster for Advanced Macromolecular Design and School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia.
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Hughes RW, Lott ME, Zastrow IS, Young JB, Maity T, Sumerlin BS. Bulk Depolymerization of Methacrylate Polymers via Pendent Group Activation. J Am Chem Soc 2024; 146:6217-6224. [PMID: 38382047 DOI: 10.1021/jacs.3c14179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
In this study, we present an efficient approach for the depolymerization of poly(methyl methacrylate) (PMMA) copolymers synthesized via conventional radical polymerization. By incorporating low mol % phthalimide ester-containing monomers during the polymerization process, colorless and transparent polymers closely resembling unfunctionalized PMMA are obtained, which can achieve >95% reversion to methyl methacrylate (MMA). Notably, our catalyst-free bulk depolymerization method exhibits exceptional efficiency, even for high-molecular-weight polymers, including ultrahigh-molecular-weight (106-107 g/mol) PMMA, where near-quantitative depolymerization is achieved. Moreover, this approach yields polymer byproducts of significantly lower molecular weight, distinguishing it from bulk depolymerization methods initiated from chain ends. Furthermore, we extend our investigation to polymethacrylate networks, demonstrating high extents of depolymerization. This innovative depolymerization strategy offers promising opportunities for the development of sustainable polymethacrylate materials, holding great potential for various applications in polymer science.
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Affiliation(s)
- Rhys W Hughes
- George & Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science & Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Megan E Lott
- George & Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science & Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Isabella S Zastrow
- George & Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science & Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - James B Young
- George & Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science & Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Tanmoy Maity
- George & Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science & Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Brent S Sumerlin
- George & Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science & Engineering, University of Florida, Gainesville, Florida 32611, United States
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Ivanchenko O, Destarac M. 1,1'- Thiocarbonyldiimidazole Radical Copolymerization for the Preparation of Degradable Vinyl Polymers. ACS Macro Lett 2024; 13:47-51. [PMID: 38118079 DOI: 10.1021/acsmacrolett.3c00676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
1,1'-Thiocarbonyldiimidazole (TCDI) readily undergoes radical copolymerization with tert-butyl acrylate (tBA), N,N-dimethylacrylamide, and styrene. 1H NMR monitoring of the comonomer reactivity revealed a notable compatibility between TCDI and comonomers, resulting in similar consumption rates when TCDI was introduced at a 10% feed ratio. Furthermore, trithiocarbonate-mediated RAFT copolymerization of TCDI with tBA gave polymers that exhibited a linear increase of molar mass (Mnth = 2-10 kg mol-1) with conversion with relatively low dispersities (1.2-1.4). Importantly, this process enabled a successful chain extension of the produced P(TCDI-co-tBA) copolymer with styrene to form a diblock copolymer. The copolymers generated through this method contain TCDI-derived diimidazolyl thioether moieties, as established through 1H NMR spectroscopy. Additionally, degradation experiments using isopropylamine, benzoyl peroxide, sodium methoxide, and bleach have provided further confirmation of the presence of degradable TCDI moieties in the vinyl copolymer backbone.
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Affiliation(s)
- Oleksandr Ivanchenko
- Laboratoire SOFTMAT, Université de Toulouse, CNRS UMR 5623, Université Toulouse III-Paul Sabatier, Toulouse 31062, France
| | - Mathias Destarac
- Laboratoire SOFTMAT, Université de Toulouse, CNRS UMR 5623, Université Toulouse III-Paul Sabatier, Toulouse 31062, France
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Hsu JH, Ball TE, Oh S, Stache EE, Fors BP. Selective Electrocatalytic Degradation of Ether-Containing Polymers. Angew Chem Int Ed Engl 2024; 63:e202316578. [PMID: 38032347 DOI: 10.1002/anie.202316578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 12/01/2023]
Abstract
Leveraging electrochemistry to degrade robust polymeric materials has the potential to impact society's growing issue of plastic waste. Herein, we develop an electrocatalytic oxidative degradation of polyethers and poly(vinyl ethers) via electrochemically mediated hydrogen atom transfer (HAT) followed by oxidative polymer degradation promoted by molecular oxygen. We investigated the selectivity and efficiency of this method, finding our conditions to be highly selective for polymers with hydridic, electron-rich C-H bonds. We leveraged this reactivity to degrade polyethers and poly(vinyl ethers) in the presence of polymethacrylates and polyacrylates with complete selectivity. Furthermore, this method made polyacrylates degradable by incorporation of ether units into the polymer backbone. We quantified degradation products, identifying up to 36 mol % of defined oxidation products, including acetic acid, formic acid, and acetaldehyde, and we extended this method to degrade a polyether-based polyurethane in a green solvent. This work demonstrates a facile, electrochemically-driven route to degrade polymers containing ether functionalities.
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Affiliation(s)
- Jesse H Hsu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, USA
| | - Tyler E Ball
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, USA
| | - Sewon Oh
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, USA
| | - Erin E Stache
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, USA
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Brett P Fors
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, USA
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Kuroda K, Ouchi M. Umpolung Isomerization in Radical Copolymerization of Benzyl Vinyl Ether with Pentafluorophenylacrylate Leading to Degradable AAB Periodic Copolymers. Angew Chem Int Ed Engl 2024; 63:e202316875. [PMID: 37971837 DOI: 10.1002/anie.202316875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/16/2023] [Accepted: 11/16/2023] [Indexed: 11/19/2023]
Abstract
This study revealed that benzyl vinyl ether (BnVE) shows a peculiar isomerization propagation in its radical copolymerization with an electron-deficient acrylate carrying a pentafluorophenyl group (PFA). The co-monomer pair inherently exhibits the cross-over propagation feature due to the large difference in the electron density. However, the radical species of PFA was found to undergo a backward isomerization to the penultimate BnVE pendant giving a benzyl radical species prior to propagation with BnVE. The isomerization brings a drastic change in the character of the growing radical species from electrophilic to nucleophilic, and thus the isomerized benzyl radial species propagates with PFA. Consequently, the two monomers were consumed in the order AAB (A: PFA; B: BnVE) and the unique periodic consumption was confirmed by the pseudo-reactivity ratios calculated by the penultimate model: r11 =0.174 and r21 =6600 for PFA (M1 ) with BnVE (M2 ). The pentafluorophenyl ester groups of the resulting copolymers are transformed into ester and amide groups by post-polymerization alcoholysis and aminolysis modifications. The unique isomerization in the AAB sequence allowed the periodic introduction of a benzyl ether structure in the backbone leading to efficient degradation under acid conditions.
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Affiliation(s)
- Keita Kuroda
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Makoto Ouchi
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
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