Transcarbamoylation in Polyurethanes: Underestimated Exchange Reactions?

Macromolecules, Journal Year: 2022, Volume and Issue: 55(18), P. 7974 - 7991

Published: Sept. 5, 2022

While transesterification has been largely explored by chemists, only a few studies comparatively dealt with its "sluggish cousin", transcarbamoylation. Originally suggested 70 years ago to explain the stress decay observed at high temperature in polyurethane chemical networks, transcarbamoylation─also called transurethanization or urethane exchange─is still underexploited both organic and polymer chemistry. This is mainly related use of toxic reactants such as isocyanates tin-based catalysts involved during preparation molecular carbamates polyurethanes (PUs) well harsh conditions required observe exchanges transformations. Many have focused their interest alternatives isocyanates, underestimating potential transcarbamoylation produce, recycle, reprocess PUs (wastes). Perspective presents latest developments plausible future directions prepare sustainable PU-based materials using focus on covalent dynamic networks.

Language: Английский

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Recycling and the end of life assessment of fluoropolymers: recent developments, challenges and future trends

Chemical Society Reviews, Journal Year: 2023, Volume and Issue: 52(13), P. 4208 - 4247

Published: Jan. 1, 2023

Herein, we present the state of art technology on recycling, reuse, thermal decomposition, and life cycle assessment fluoropolymers (FPs, ranging from PTFE PVDF to various fluorinated copolymers based VDF TFE).

Language: Английский

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On the Welding of Vitrimers: Chemistry, Mechanics and Applications

Advanced Functional Materials, Journal Year: 2023, Volume and Issue: 33(36)

Published: May 18, 2023

Abstract Linear chains in thermoplastics make them relatively weak performance but inherently weldable and recyclable. By contrast, thermosets with permanently crosslinked networks possess outstanding mechanical performance, thermal, chemical stability, are unweldable unrecyclable. In the last decade, a kind of thermoplastics‐like termed as vitrimer has been developed extensive applications, which welding vitrimers plays central fundamental role. Herein, we present current state art discuss from broad picture chemistry, physics, mechanics: i) chemistry mechanics vitrimers; ii) applicability assessment methods for iii) design principles implement strategies to iv) effects conditions on strength toughness; v) applications adhesion chemically inert materials. Finally, advantages, challenges, open questions highlighted, future opportunities mechanics, tough welding, artificial intelligence aided programming technology, standard, so discussed. The development would fuse disciplines transformative impact polymer industry.

Language: Английский

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High-Strength and Multi-Recyclable Epoxy Vitrimer Containing Dual-Dynamic Covalent Bonds Based on the Disulfide and Imine Bond Metathesis

ACS Sustainable Chemistry & Engineering, Journal Year: 2023, Volume and Issue: 11(39), P. 14591 - 14600

Published: Sept. 12, 2023

Epoxy (EP) vitrimers are currently regarded as ideal substitutes for traditional thermosetting resins, this class of materials combines the advantages thermoplastic and thermoset polymers. However, maintaining high performance EP with excellent healing properties remains a challenge. In work, novel hardener combining disulfide imine bonds through reaction Schiff base (4-AFD-VAN) was designed then used to prepare vitrimer dual-dynamic covalent bonds. Compared single-disulfide-containing (EVP-4-AFD), prepared (EPV-4-AFD-VAN) exhibited lower activation energy faster stress relaxation. Moreover, EPV-4-AFD-VAN showed tensile strength up 71.5 MPa maintained recovery ratio approximately 90.0% during three cycles. Similar EP, retained its good solvent resistance, breakdown strength, dielectric properties, which can be chemically degraded in suitable solvents, demonstrating environmental sustainability.

Language: Английский

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Strong yet Tough Catalyst‐Free Transesterification Vitrimer with Excellent Fire‐Retardancy, Durability, and Closed‐Loop Recyclability

Small, Journal Year: 2024, Volume and Issue: 20(45)

Published: July 31, 2024

Despite great advances in vitrimer, it remains highly challenging to achieve a property portfolio of excellent mechanical properties, desired durability, and high fire safety. Thus, catalyst-free, closed-loop recyclable transesterification vitrimer (TPN

Language: Английский

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Robust Epoxy Resins with Autonomous Visualization of Damaging‐Healing and Green Closed‐Loop Recycling

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: unknown

Published: June 29, 2024

Abstract Epoxy resins‐based engineering plastics are indispensable in the global economy, but they have created a serious waste crisis caused by their chemical cross‐linked networks. To solve this problem, current strategies often require assistance of catalysts or solvents at expense thermal and mechanical performance. In work, high‐performance epoxy resin featuring dynamic ester disulfide bonds (TDS) is reported, which exhibits higher properties than common plastics, i.e., tensile strength modulus 66.6 MPa 2.63 GPa, flexural 103.2 3.52 glass transition temperature ( T g ) 133 °C. Moreover, reversible transformation between aromatic thiyl radicals endows TDS with autonomous visualization damage healing. addition, harmonious interplay bonds‐promoted tertiary amine accelerated topological network rearrangements, enabling to easily reshape weld. Specifically, can be completely degraded pure water 200 °C without any catalyst, products directly re‐polymerized achieve green closed‐loop recycling. This work proposes simple economical strategy for development resin‐based cutting‐edge that both functional sustainable.

Language: Английский

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Multiscale hierarchical composite with extremely specific damping performance via bottom-up synergistic enhancement strategy

Virtual and Physical Prototyping, Journal Year: 2025, Volume and Issue: 20(1)

Published: Jan. 6, 2025

Existing hierarchical damping composites focus on either the intrinsic sources at nanoscale or excitation effect mesoscale, resulting in limited improvement performance. This paper proposes a multiscale synergistic strategy for enhancement and creates with extremely specific In addition to traditional physical source nanoscale, chemical is introduced. Considering carbon nanotubes-induced features as micro-hierarchy skeleton lattices meso-hierarchy, microstructure of hard phase each level composite material structure designed utilise both their rigidity-enhancing by guiding hard-phase-driven deformation mechanism. The achieves loss modulus up 1.54 GPa, surpassing conventional engineering materials. work offers bottom-up design opens transformational path toward high-performance composites.

Language: Английский

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A transparent epoxy vitrimer with outstanding flame retardancy, toughness, and recyclability enabled by a hyperbranched P/N-derived polyester

Construction and Building Materials, Journal Year: 2025, Volume and Issue: 470, P. 140673 - 140673

Published: March 6, 2025

Language: Английский

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The role of tertiary amines as internal catalysts for disulfide exchange in covalent adaptable networks

Polymer Chemistry, Journal Year: 2023, Volume and Issue: 14(6), P. 680 - 686

Published: Jan. 1, 2023

True effects of internal tertiary amines on disulfide exchange in cross-linked networks are explored, which provides the knowledge for creation functional materials with efficient bond properties.

Language: Английский

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Reprocessible Triketoenamine‐Based Vitrimers with Closed‐Loop Recyclability

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(34)

Published: June 14, 2023

Development of thermosets that can be repeatedly recycled via both chemical route (closed-loop) and thermo-mechanical process is attractive remains an imperative task. In this work, we reported a triketoenamine based dynamic covalent network derived from 2,4,6-triformylphloroglucinol secondary amines. The resulting does not have intramolecular hydrogen bonds, thus reducing its π-electron delocalization, lowering the stability tautomer structure, enabling feature. By virtue highly reversible bond exchange, novel enables easy construction crosslinked chemically reprocessable networks commercially available monomers. as-made polymer monoliths exhibit high mechanical properties (tensile strength 79.4 MPa Young's modulus 571.4 MPa) undergo monomer-network-monomer (yields up to 90 %) recycling mediated by aqueous solution, with new-generation capable restoring material original state. addition, owing nature, catalyst-free low-temperature reprogrammable adaptable (vitrimer) was achieved. design concept herein applied development other vitrimers repressibility recyclability, sheds light on future sustainable polymers minimal environmental impact.

Language: Английский

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