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De Alwis Watuthanthrige N, Whitfield R, Harrisson S, Truong NP, Anastasaki A. Thermal Solution Depolymerization of RAFT Telechelic Polymers. ACS Macro Lett 2024:806-811. [PMID: 38857492 DOI: 10.1021/acsmacrolett.4c00286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Thermal solution depolymerization is a promising low-temperature chemical recycling strategy enabling high monomer recovery from polymers made by controlled radical polymerization. However, current methodologies predominantly focus on the depolymerization of monofunctional polymers, limiting the material scope and depolymerization pathways. Herein, we report the depolymerization of telechelic polymers synthesized by RAFT polymerization. Notably, we observed a significant decrease in the molecular weight (Mn) of the polymers during monomer recovery, which contrasts the minimal Mn shift observed during the depolymerization of monofunctional polymers. Introducing Z groups at the center or both ends of the polymer resulted in distinct kinetic profiles, indicating partial depolymerization of the bifunctional polymers, as supported by mathematical modeling. Remarkably, telechelic polymers featuring R-terminal groups showed up to 68% improvement in overall depolymerization conversion compared to their monofunctional analogues, highlighting the potential of these materials in chemical recycling and the circular economy.
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Affiliation(s)
| | - Richard Whitfield
- Laboratory of Polymeric Materials, Department of Materials, ETH Zurich, Zurich, 8093, Switzerland
| | - Simon Harrisson
- Laboratoire de Chimie des Polymères Organiques, University of Bordeaux/Bordeaux-INP/CNRS UMR5629, Pessac 33607, France
| | - Nghia P Truong
- Laboratory of Polymeric Materials, Department of Materials, ETH Zurich, Zurich, 8093, Switzerland
| | - Athina Anastasaki
- Laboratory of Polymeric Materials, Department of Materials, ETH Zurich, Zurich, 8093, Switzerland
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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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3
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Mountaki SA, Whitfield R, Parkatzidis K, Antonopoulou MN, Truong NP, Anastasaki A. Chemical recycling of bromine-terminated polymers synthesized by ATRP. RSC APPLIED POLYMERS 2024; 2:275-283. [PMID: 38525379 PMCID: PMC10955525 DOI: 10.1039/d3lp00279a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 01/25/2024] [Indexed: 03/26/2024]
Abstract
Chemical recycling of polymers is one of the biggest challenges in materials science. Recently, remarkable achievements have been made by utilizing polymers prepared by controlled radical polymerization to trigger low-temperature depolymerization. However, in the case of atom transfer radical polymerization (ATRP), depolymerization has nearly exclusively focused on chlorine-terminated polymers, even though the overwhelming majority of polymeric materials synthesized with this method possess a bromine end-group. Herein, we report an efficient depolymerization strategy for bromine-terminated polymethacrylates which employs an inexpensive and environmentally friendly iron catalyst (FeBr2/L). The effect of various solvents and the concentration of metal salt and ligand on the depolymerization are judiciously explored and optimized, allowing for a depolymerization efficiency of up to 86% to be achieved in just 3 minutes. Notably, the versatility of this depolymerization is exemplified by its compatibility with chlorinated and non-chlorinated solvents, and both Fe(ii) and Fe(iii) salts. This work significantly expands the scope of ATRP materials compatible with depolymerization and creates many future opportunities in applications where the depolymerization of bromine-terminated polymers is desired.
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Affiliation(s)
- Stella Afroditi Mountaki
- Laboratory of Polymeric Materials, Department of Materials, ETH Zurich Vladimir-Prelog-Weg-5 8093 Zurich Switzerland
| | - Richard Whitfield
- Laboratory of Polymeric Materials, Department of Materials, ETH Zurich Vladimir-Prelog-Weg-5 8093 Zurich Switzerland
| | - Kostas Parkatzidis
- Laboratory of Polymeric Materials, Department of Materials, ETH Zurich Vladimir-Prelog-Weg-5 8093 Zurich Switzerland
| | - Maria-Nefeli Antonopoulou
- Laboratory of Polymeric Materials, Department of Materials, ETH Zurich Vladimir-Prelog-Weg-5 8093 Zurich Switzerland
| | - Nghia P Truong
- Laboratory of Polymeric Materials, Department of Materials, ETH Zurich Vladimir-Prelog-Weg-5 8093 Zurich Switzerland
| | - Athina Anastasaki
- Laboratory of Polymeric Materials, Department of Materials, ETH Zurich Vladimir-Prelog-Weg-5 8093 Zurich 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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Lohmann V, Jones GR, Truong NP, Anastasaki A. The thermodynamics and kinetics of depolymerization: what makes vinyl monomer regeneration feasible? Chem Sci 2024; 15:832-853. [PMID: 38239674 PMCID: PMC10793647 DOI: 10.1039/d3sc05143a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/28/2023] [Indexed: 01/22/2024] Open
Abstract
Depolymerization is potentially a highly advantageous method of recycling plastic waste which could move the world closer towards a truly circular polymer economy. However, depolymerization remains challenging for many polymers with all-carbon backbones. Fundamental understanding and consideration of both the kinetics and thermodynamics are essential in order to develop effective new depolymerization systems that could overcome this problem, as the feasibility of monomer generation can be drastically altered by tuning the reaction conditions. This perspective explores the underlying thermodynamics and kinetics governing radical depolymerization of addition polymers by revisiting pioneering work started in the mid-20th century and demonstrates its connection to exciting recent advances which report depolymerization reaching near-quantitative monomer regeneration at much lower temperatures than seen previously. Recent catalytic approaches to monomer regeneration are also explored, highlighting that this nascent chemistry could potentially revolutionize depolymerization-based polymer recycling in the future.
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Affiliation(s)
- Victoria Lohmann
- Laboratory of Polymeric Materials, Department of Materials, ETH Zürich Vladimir-Prelog-Weg 5 8093 Zürich Switzerland
| | - Glen R Jones
- Laboratory of Polymeric Materials, Department of Materials, ETH Zürich Vladimir-Prelog-Weg 5 8093 Zürich Switzerland
| | - Nghia P Truong
- Laboratory of Polymeric Materials, Department of Materials, ETH Zürich Vladimir-Prelog-Weg 5 8093 Zürich Switzerland
- Monash Institute of Pharmaceutical Sciences, Monash University 399 Royal Parade Parkville VIC 3152 Australia
| | - Athina Anastasaki
- Laboratory of Polymeric Materials, Department of Materials, ETH Zürich Vladimir-Prelog-Weg 5 8093 Zürich Switzerland
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Mineo AM, Katsumata R. A Versatile Comonomer Additive for Radically Recyclable Vinyl-derived Polymers. Angew Chem Int Ed Engl 2024; 63:e202316248. [PMID: 38029360 DOI: 10.1002/anie.202316248] [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: 10/26/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/01/2023]
Abstract
Radically-formed, vinyl-derived polymers account for over 30 % of polymer production. Connected through stable carbon-carbon bonds, these materials are notoriously challenging to chemically recycle. Herein, we report universal copolymerization of a cyclic allyl sulfide (CAS) additive with multiple monomers under free-radical conditions, to introduce main-chain dynamic motifs. Backbone allyl sulfides undergo post-polymerization radical rearrangement via addition-fragmentation-transfer (AFT) that fosters both chain scission and extension. Scission is selectively induced through allyl sulfide exchange with small molecule thiyl radicals, resulting in oligomers as low as 14 % of the initial molar mass. Crucially, oligomers retain allyl sulfide end groups, enabling their extension with monomer under radical conditions. Extended, i.e., recycled, product molar mass is tunable through the ratio of monomer to oligomer, and can surpass that of the initial copolymer. Two scission-extension cycles are demonstrated in copolymers with methyl methacrylate and styrene without escalation in dispersity. In illustration of forming higher-value products, i.e., upcycling, we synthesized block copolymers through the extension of oligomers with a different vinyl monomer. Collectively, our approach to chemical recycling is unparalleled in its ability to 1) function in a variety of vinyl-derived polymers, 2) complete radical closed-loop cycling, and 3) upcycle waste material.
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Affiliation(s)
- Autumn M Mineo
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Reika Katsumata
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA
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Zhao R, Wang C, Huang K, Li L, Fan W, Zhu Q, Ma H, Wang X, Wang Z, Huang W. Macromolecular Engineered Multifunctional Room-Temperature Phosphorescent Polymers through Reversible Deactivation Radical Polymerization. J Am Chem Soc 2023. [PMID: 38035385 DOI: 10.1021/jacs.3c10673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Despite the intensive research in room-temperature phosphorescent (RTP) polymers, the synthesis of RTP polymers with well-defined macromolecular structures and multiple functions remains a challenge. Herein, reversible deactivation radical polymerization was demonstrated to offer a gradient copolymer (GCP) architecture with controlled heterogeneities, which combines hard segment and flexible segment. The GCPs would self-assemble into a multiphase nanostructure, featuring tunable stretchability, excellent RTP performance, and intrinsic healability without compromising light emission under stretching. The mechanical performance is tunable on demand with elongation at break ranging from 5.0% to 221.7% and Young's modulus ranging from 0.5 to 225.0 MPa.
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Affiliation(s)
- Ruoqing Zhao
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
| | - Chen Wang
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
| | - Keer Huang
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
| | - Lei Li
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
| | - Wenru Fan
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
| | - Qixuan Zhu
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
| | - Huihui Ma
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
| | - Xuewen Wang
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
| | - Zhenhua Wang
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
| | - Wei Huang
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi'an 710072, China
- State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China
- Key Laboratory of Flexible Electronics (KLoFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
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