Closed-loop chemical recycling of thermosetting polymers and their applications: a review

Liu, Yanlin; Yu, Zhen; Wang, Binbo; Li, Pengyun; Zhu, Jin; Ma, Songqi

doi:10.1039/d2gc00368f

Cited by 71 publications

(72 citation statements)

References 104 publications

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“…Several studies consider the introduction of active covalent bonds in the epoxy system triggered by external stimuli, such as heat, light or irradiation [ 56 , 57 , 58 , 59 , 60 ]; although the ideal recovery rate is 100%, the high energy employed in the process leads to poorer performance of the recovered material compared with that of the original thermosets because of degradation [ 61 ].…”

Section: Thermoset With Built-in Recyclabilitymentioning

confidence: 99%

Recycling of Thermoset Materials and Thermoset-Based Composites: Challenge and Opportunity

Morici

Dintcheva

2022

Polymers

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Thermoset materials and their composites are characterized by a long life cycle with their main applications in aircrafts, wind turbines and constructions as insulating materials. Considering the importance of recovery and valorization of these materials at their end-of-life, avoiding landfilling, the interest concerning their recycling grows continuously. The thermoset materials and their composites, to be successfully recovered and valorized, must degrade their three-dimensional structures and recover the mono-oligomers and/or fillers. The thermoset materials could successfully degrade through thermal treatment at different temperatures (for example, above 1000 °C for incineration, ca. 500 °C for oxidation/combustion of organic constituents, etc.), chemical degradation by catalyst, irradiation with or without the presence of water, alcohol, etc., and mechanical recycling, obtaining fine particles that are useful as filler and/or reinforcement additives. Among these recycling methods, this mini-review focuses on the formulation and recovery method of innovative thermoset with in-build recyclability, i.e., materials having chemical links that could be degraded on-demand or containing dynamic covalent bonds to have re-processable and/or recyclable thermoset. This issue could be considered the future perspective in developing novel thermoset materials. The aim of this review is to get an overview of the state of the art in thermoset recycling and of the most commonly used thermoset composites, recovering valuable reinforcing fibers. Additionally, in this work, we also report not only known recycling routes for thermoset and thermoset-based composites, but also new and novel formulating strategies for producing thermosets with built-in recyclability, i.e., containing chemical-triggered on-demand links. This mini-review is also a valuable guide for educational purposes for students and specialized technicians in polymer production and recycling.

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Section: Thermoset With Built-in Recyclabilitymentioning

confidence: 99%

Recycling of Thermoset Materials and Thermoset-Based Composites: Challenge and Opportunity

Morici

Dintcheva

2022

Polymers

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“…3 To address these issues, various recycling methods have been proposed to achieve sustainable management of waste. 4,5 They can be mainly classified into energy recycling, physical recycling and chemical recycling, and chemical recycling can be subdivided into pyrolysis and solvolysis. These recycling approaches, as well as their advantages and disadvantages, have been briefly discussed here.…”

Section: Introductionmentioning

confidence: 99%

Upcycling of thermosetting polymers into high-value materials

Wang

et al. 2023

Mater. Horiz.

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“…22 However, the emission of toxic decomposition products will pollute the atmosphere, and excess carbon emissions will exacerbate the greenhouse effect. 23 An optimal way is to realize the chemical recycling of polymeric monomers. 24,25 PHU networks can be easily recycled back to monomers to establish chemical recycling because of the relatively high reactivity of the urethane C−O bond.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Incineration and pyrolysis are two “waste-to-energy” strategies for recycling energy from waste thermosets . However, the emission of toxic decomposition products will pollute the atmosphere, and excess carbon emissions will exacerbate the greenhouse effect . An optimal way is to realize the chemical recycling of polymeric monomers. , PHU networks can be easily recycled back to monomers to establish chemical recycling because of the relatively high reactivity of the urethane C–O bond. , A few reports have been carried out on the chemical recycling of PHU.…”

Section: Introductionmentioning

confidence: 99%

Mechanically Robust and Chemically Recyclable Polyhydroxyurethanes from CO₂-Derived Six-Membered Cyclic Carbonates

Miao

Jiao

Liu

et al. 2022

ACS Appl. Mater. Interfaces

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In the current context of sustainable chemistry development and new regulations, aminolysis of cyclic carbonate is one of the most promising routes to nonisocyanate polyurethanes, also called polyhydroxyurethanes (PHU). In this study, a new kind of shape memory PHU vitrimers with outstanding mechanical properties and chemical recyclability is prepared. The monomer employed for aminolysis to form the PHUs is bis(six-membered cyclic carbonate) of 4,4′-biphenol (BCC-BP), which is synthesized by bi(1,3-diol) precursors and CO 2 . The synthetic strategy, isocyanate-free and employing CO 2 as a building block, is environmentally friendly and suits the concept of carbon neutrality. The thermal properties, mechanical properties, and dynamic behaviors of the PHUs are explored. The maximum breaking strength and elongation at break of the resultant PHUs reach 65 MPa and 452%, respectively, exceeding other reported PHU-based materials in combined performance. Such a PHU material can also lift up a load 4700 times heavier than its own weight by a shape recovery process. Finally, the bi(1,3-diol) can be regenerated through the alcoholysis of PHUs to realize chemical recycling. This work provides a feasibility study for a green synthetic approach and for designing a novel PHU material with outstanding properties.

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Closed-loop chemical recycling of thermosetting polymers and their applications: a review

Abstract: Conventional thermosets are infusible and insoluble covalently cross-linked polymers which are difficult to be recycled and reused when discarded. Recent years witnessed development of closed-loop recycling of novel thermosets as...

Cited by 71 publications

References 104 publications

Recycling of Thermoset Materials and Thermoset-Based Composites: Challenge and Opportunity

Recycling of Thermoset Materials and Thermoset-Based Composites: Challenge and Opportunity

Upcycling of thermosetting polymers into high-value materials

Mechanically Robust and Chemically Recyclable Polyhydroxyurethanes from CO₂-Derived Six-Membered Cyclic Carbonates

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Closed-loop chemical recycling of thermosetting polymers and their applications: a review

Abstract: Conventional thermosets are infusible and insoluble covalently cross-linked polymers which are difficult to be recycled and reused when discarded. Recent years witnessed development of closed-loop recycling of novel thermosets as...

Cited by 71 publications

References 104 publications

Recycling of Thermoset Materials and Thermoset-Based Composites: Challenge and Opportunity

Recycling of Thermoset Materials and Thermoset-Based Composites: Challenge and Opportunity

Upcycling of thermosetting polymers into high-value materials

Mechanically Robust and Chemically Recyclable Polyhydroxyurethanes from CO2-Derived Six-Membered Cyclic Carbonates

Contact Info

Product

Resources

About

Mechanically Robust and Chemically Recyclable Polyhydroxyurethanes from CO₂-Derived Six-Membered Cyclic Carbonates