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Ko K, Lundberg DJ, Johnson AM, Johnson JA. Mechanism-Guided Discovery of Cleavable Comonomers for Backbone Deconstructable Poly(methyl methacrylate). J Am Chem Soc 2024; 146:9142-9154. [PMID: 38526229 DOI: 10.1021/jacs.3c14554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
The development of cleavable comonomers (CCs) with suitable copolymerization reactivity paves the way for the introduction of backbone deconstructability into polymers. Recent advancements in thionolactone-based CCs, exemplified by dibenzo[c,e]-oxepine-5(7H)-thione (DOT), have opened promising avenues for the selective deconstruction of multiple classes of vinyl polymers, including polyacrylates, polyacrylamides, and polystyrenics. To date, however, no thionolactone CC has been shown to copolymerize with methacrylates to an appreciable extent to enable polymer deconstruction. Here, we overcome this challenge through the design of a new class of benzyl-functionalized thionolactones (bDOTs). Guided by detailed mechanistic analyses, we find that the introduction of radical-stabilizing substituents to bDOTs enables markedly increased and tunable copolymerization reactivity with methyl methacrylate (MMA). Through iterative optimizations of the molecular structure, a specific bDOT, F-p-CF3PhDOT, is discovered to copolymerize efficiently with MMA. High molar mass deconstructable PMMA-based copolymers (dPMMA, Mn > 120 kDa) with low percentages of F-p-CF3PhDOT (1.8 and 3.8 mol%) are prepared using industrially relevant bulk free radical copolymerization conditions. The thermomechanical properties of dPMMA are similar to PMMA; however, the former is shown to degrade into low molar mass fragments (<6.5 kDa) under mild aminolysis conditions. This work presents the first example of a radical ring-opening CC capable of nearly random copolymerization with MMA without the possibility of cross-linking and provides a workflow for the mechanism-guided design of deconstructable copolymers in the future.
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Affiliation(s)
- Kwangwook Ko
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - David J Lundberg
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Alayna M Johnson
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jeremiah A Johnson
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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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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Karlsson MB, Benedini L, Jensen CD, Kamp A, Henriksen UB, Thomsen TP. Climate footprint assessment of plastic waste pyrolysis and impacts on the Danish waste management system. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 351:119780. [PMID: 38091733 DOI: 10.1016/j.jenvman.2023.119780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 11/17/2023] [Accepted: 12/03/2023] [Indexed: 01/14/2024]
Abstract
Increased plastic recycling is necessary to reduce environmental impacts related to manufacturing and end-of-life of plastic products, however, mechanical recycling (MR) - currently the most widespread recycling option for plastic waste - is limited by quality requirements for inputs and reduced quality of outputs. In this study, pyrolysis of plastic waste is assessed against MR, municipal solid waste incineration (MSWI) and fuel substitution through climate footprint assessment (CFA) based on primary data from pyrolysis of plastic waste sourced from Danish waste producers. Results of the CFA are scaled to the Danish plastic waste resource in an impact assessment of current Danish plastic waste management, and scenarios are constructed to assess reductions through utilization of pyrolysis. Results of the CFA show highest benefits utilizing pyrolysis for monomer recovery (-1400 and -4800 kg CO2e per ton polystyrene (PS) and polymethyl methacrylate (PMMA), respectively) and MR for single polymer polyolefins (-1000 kg CO2e per ton PE). The two management options perform similarly with mixed plastic waste (200 kg CO2e per ton plastic waste). MSWI has the highest impact (1600-2200 kg CO2e per ton plastic waste) and should be avoided when alternatives are available. Scaling the results of the CFA to the full Danish plastic waste resource reveals an impact of 0.79 Mt CO2e in year 2020 of current plastic waste management. Utilizing pyrolysis to manage MR residues reduces the system impact by 15%. Greater reductions are possible through increased separation of plastic from residual waste. The best performance is achieved through a combination of MR and pyrolysis.
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Affiliation(s)
- M B Karlsson
- Roskilde University, Institute of People and Technology, Universitetsvej 1, 4000, Roskilde, Denmark.
| | - L Benedini
- Technical University of Denmark, Department of Chemical and Biochemical Engineering, CHEC Research Centre, Miljøvej, 2800, Kgs. Lyngby, Denmark
| | - C D Jensen
- Technical University of Denmark, Department of Chemical and Biochemical Engineering, CHEC Research Centre, Miljøvej, 2800, Kgs. Lyngby, Denmark
| | - A Kamp
- Roskilde University, Institute of People and Technology, Universitetsvej 1, 4000, Roskilde, Denmark
| | - U B Henriksen
- Technical University of Denmark, Department of Chemical and Biochemical Engineering, CHEC Research Centre, Miljøvej, 2800, Kgs. Lyngby, Denmark
| | - T P Thomsen
- Roskilde University, Institute of People and Technology, Universitetsvej 1, 4000, Roskilde, Denmark
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