A Highly Dynamic Covalent Polymer Network without Creep: Mission Impossible?

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(48)

Published: Sept. 26, 2022

Dynamic covalent polymer networks provide an interesting solution to the challenging recyclability of thermosets and elastomers. One remaining design constraints, however, is balancing thermal reprocessability in form material flow with dimensional stability during use. As a result, many chemistries are being investigated order improve bond reactivity control robustness. This Minireview highlights number promising concepts, particular emphasis on disconnecting chemical low high temperature regimes obtain creep resistant, yet highly dynamic networks. In addition, we will highlight impact sharp changes when applying extrapolation-based approaches rheological analysis. confident that abandoning myth "permanent" aid development sustainable polymeric materials can truly combine benefits thermoplastic thermoset behaviour.

Language: Английский

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Structure–Property Relationships of Elastomeric Vinylogous Urethane Thermosets and Their Application as Closed-Loop Recyclable Strain Sensors

Macromolecules, Journal Year: 2025, Volume and Issue: 58(4), P. 1923 - 1934

Published: Feb. 5, 2025

Developing closed-loop recyclable thermosets and understanding their structure–property relationships are essential steps in advancing a circular materials economy. Here, we present vinylogous urethane (VU) thermoset with recyclability, synthesized through the reaction of polytetrahydrofuran bisacetoacetate (aPTHF) tris(2-aminoethyl)amine (TREN). These VU polymers exhibit high elasticity, only 3–9% residual strain observed after cyclic tensile testing at maximum 100%, depending on molecular weight aPTHF network cross-link density. The two structural parameters also allow modulation mechanical stress-relaxation properties elastomers. To investigate hydrolysis linkages within hydrophobic matrix, employed heterogeneous system using biphasic mixture HCl CDCl3. Our findings show that VUs remain stable pure water but can be dissociated under acidic conditions, dissociation rate accelerated higher temperatures and/or presence concentrations. detailed investigations indicate potential elastomers as sustainable substrates for wearable sensors. We therefore conduct case study synthesizing sensor incorporation multiwalled carbon nanotubes (MCNs) into elastomer matrix. robustly detect various movements. Moreover, treatment both neat polymer composite diethyl ether solvent allows excellent recovery (>90%) TREN (86%), without discernible damage to MCNs reclaimed from latter.

Language: Английский

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Closed‐Loop Recycling of Vinylogous Urethane Vitrimers

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(36)

Published: July 13, 2023

Devising energy-efficient strategies for the depolymerization of plastics and recovery their structural components in high yield purity is key to a circular economy. Here, we report case study which demonstrate that vinylogous urethane (VU) vitrimers synthesized from bis-polyethylene glycol acetoacetates (aPEG) tris(2-aminoethyl)amine can be degraded by water at moderate temperature with almost quantitative (≈98 %) aPEG. The rate controlled temperature, amount water, molecular weight aPEG, composition starting material. These last two parameters also allow one tailor mechanical properties final materials, this was used access soft, tough, brittle vitrimers, respectively. straightforward preparation aPEG-based VU are interesting elements design polymer materials enhanced closed-loop recycling characteristics.

Language: Английский

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“Acrostic” Encryption: Stress‐Manipulation on Information Display

Advanced Functional Materials, Journal Year: 2023, Volume and Issue: 33(31)

Published: April 9, 2023

Abstract Polymers are ideal materials for information printing and storage encryption through multiple channels. In this study, the visible color, fluorescent, stress‐color combined to print information. Stress‐color is achieved using an acid‐tunable dynamic reaction between a β‐diketone amine group via light‐induced transformation of spiropyran (SP), which also directly prints color The fluorescent patterns stable SP released from enaminone structure. By achieving coding, data further encrypted in “acrostic” form by programmatically coding at several stages. pattern or closely related decoding strain, whereas display all written various strains. As result, secret hidden among public data, resulting acrostic encryption.

Language: Английский

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Fully biobased sustainable elastomers derived from chitin, lignin, and plant oil via grafting strategy and Schiff-base chemistry

Carbohydrate Polymers, Journal Year: 2023, Volume and Issue: 305, P. 120577 - 120577

Published: Jan. 11, 2023

Language: Английский

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Vinylogous Urea—Urethane Vitrimers: Accelerating and Inhibiting Network Dynamics through Hydrogen Bonding

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(9)

Published: Jan. 10, 2024

Vinylogous urethane (VU

Language: Английский

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Polybenzoxazine-based covalent adaptable networks: A mini-review

Polymer, Journal Year: 2023, Volume and Issue: 287, P. 126426 - 126426

Published: Oct. 25, 2023

Benzoxazines represent a class of thermoset resins known for their exceptional thermal, fire, and mechanical properties. These find wide applications in various industries, including composites electronic components. However, like conventional thermosets, benzoxazines have limitations terms end-of-life options, typically being landfilled or incinerated. To address this concern, researchers been exploring the incorporation dynamic bonds into structure polybenzoxazines to add functionalities such as reprocessability, self-healing, recycling capabilities, develop polybenzoxazine-based covalent adaptable networks (CANs). This mini-review offers an overview recent endeavors focused on introduction within polybenzoxazine structures. It emphasizes synergies between molecular exchanges, transesterification disulfide metathesis, provides comparative summary properties achieved by materials developed context. By leveraging strengths benzoxazine structures, aims foster exploration development innovative approaches that combine unique CANs, enabling more sustainable environmentally friendly materials.

Language: Английский

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Aza-Michael Chemistry for PDMS-Based Covalent Adaptable Elastomers: Design and Dual Role of the Silica Filler

Macromolecules, Journal Year: 2024, Volume and Issue: 57(10), P. 4817 - 4825

Published: May 7, 2024

In this study, polydimethylsiloxane (PDMS)-based covalent adaptable networks have been prepared in a one-pot, catalyst-free way which dynamic β-amino esters (BAEs) are introduced via aza-Michael addition between available acrylate/amine-terminated PDMS-compounds. The straightforward introduction of those BAE-groups such high-value elastomers provides the ability to relax applied stress at elevated temperatures and hence capability reshaping by compression molding least 5 times without significant changes properties. Moreover, mechanical properties tunable varying cross-linker and/or filler content. Interestingly, utilization silica fillers not only enhances network formation but also accelerates exchange reactions, resulting twice faster relaxation while maintaining creep resistance service temperatures.

Language: Английский

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Tuning the Dynamics of Enamine-One-Based Vitrimers through Substituent Modulation of Secondary Amine Substrates

Macromolecules, Journal Year: 2022, Volume and Issue: 55(22), P. 10124 - 10133

Published: Nov. 3, 2022

Polymer networks embedded with dynamic covalent bonds have been demonstrated to be capable of network reconfiguration. This reprocessability is often related the dynamics or flowability, precise control which highly depends on underlying chemistry. Particularly, vitrimer materials flow at a constant crosslinking density because associative chemistry involved. Here, we report fabrication enamine-one vitrimers through an amino-yne click reaction using secondary amine substrates. Compared primary amines, amine-based mild and yields less gel content (70 vs 97%) in our curing system. By modulating substituents amine, show that activation energy exchange increases (52–90 kJ/mol) increasing steric hindrance (piperidyl ∼ methyl < ethyl isopropyl tert-butyl), similar trend was observed networks. Interestingly, piperidine exhibits reactivities (including yielded dynamics) comparable amines constrained cyclic structure. study not only enriches scope substrates for but also offers convenient means tune substrate choices combination strategies (i.e., mixing various amines).

Language: Английский

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Harnessing β-Hydroxyl Groups in Poly(β-Amino Esters) toward Robust and Fast Reprocessing Covalent Adaptable Networks

Macromolecules, Journal Year: 2022, Volume and Issue: 55(23), P. 10366 - 10376

Published: Nov. 28, 2022

Poly(β-amino esters) (PBAEs), which include tertiary amines at the β-position of ester linkages, are promising in biomaterials due to their biodegradability and pH responsiveness. Such characteristics molecular structure also appealing for designing catalyst-free covalent adaptable networks (CANs), but this has rarely been explored literature. Herein, we synthesize a series PBAE-based CANs by aza-Michael addition, using diacrylate monomers with without β-hydroxyl groups, triamine crosslinker. By leveraging hydrogen bonding, thermal mechanical properties these effectively tuned through monomer composition. Owing numerous serving as internal catalysts, undergo network exchange dynamic reaction. Interestingly, increasing amount groups accelerates overall stress relaxation from synergistic effects transesterification (associative type) lower temperatures reaction (dissociative higher temperatures. Based on features, successfully demonstrate reprocessing healing elevated under mild pressure, well shape memory reconfiguration. Thus, controlling group concentration is useful strategy enhancing both strength rate.

Language: Английский

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