Neighboring Group Participation and Internal Catalysis Effects on Exchangeable Covalent Bonds: Application to the Thriving Field of Vitrimer Chemistry

Cuminet, Florian; Caillol, Sylvain; Dantras, Éric; Leclerc, E.; Ladmiral, Vincent

doi:10.1021/acs.macromol.0c02706

Cited by 111 publications

(132 citation statements)

References 261 publications

(743 reference statements)

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“…To overcome this issue, internal catalysis or neighboring group participation were envisaged. [ 80 ] Williams and coworkers reported one example of fully biobased vitrimer that did not require the use of additional catalyst. [ 81 ] The authors cross‐linked epoxidized soybean oil ( E1 , Figure 4) with an aqueous solution of citric acid ( A1 , Figure 5).…”

Section: Transesterification Reactionsmentioning

confidence: 99%

Fully Biobased Vitrimers: Future Direction toward Sustainable Cross‐Linked Polymers

Vidil

Llevot

2022

Macro Chemistry & Physics

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Improving the sustainability of polymer networks is a crucial challenge in polymer science due to their important role in industry. Their traditional syntheses conflict with several principles of green chemistry as the employed monomers are petroleum-based, their production involves the use of toxic reagents, and their permanently cross-linked structures impede their chemical recycling and reshaping. The development of vitrimers represents a unique solution to address the issue of polymer network end-of-life by enabling reprocessability while maintaining good thermomechanical properties and solvent resistance. Although over the last decades biomass has proved to be an excellent feedstock for the production of permanently cross-linked polymers, the field of biobased vitrimers is still in its infancy. In this review, a comprehensive overview of vitrimers synthesized from biobased monomers is presented. The emphasis is set on the compatibility of the biomass structure with the nature of the dynamic covalent chemistry, as well as the sustainability of the synthetic approaches. Implementing renewable feedstocks and recyclability in the production of polymer networks paves the way for the development of the next generation of sustainable materials.

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Section: Transesterification Reactionsmentioning

confidence: 99%

Fully Biobased Vitrimers: Future Direction toward Sustainable Cross‐Linked Polymers

Vidil

Llevot

2022

Macro Chemistry & Physics

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“…24,25 Recently, neighboring group participation has been introduced as a strategy to accelerate exchange reactions in DCNs. 26,27 Involvement of a functional group close to the exchanging moiety increases the reaction rate by providing a low free energy pathway to exchange via formation of a cyclic intermediate, a dissociative process. In their seminal work, Du Prez and co-workers showed a neighboring carboxylic acid group-participated transesterification of a phthalic acid derivative via a reactive anhydride intermediate.…”

Section: ■ Introductionmentioning

confidence: 99%

Dynamic Polyamide Networks via Amide–Imide Exchange

et al. 2021

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The diamide–imide equilibrium was successfully exploited for the synthesis of dynamic covalent polymer networks in which a dissociative bond exchange mechanism leads to high processibility at temperatures above ≈110 °C. Dynamic covalent networks bridge the gap between thermosets and thermoplastic polymers. At the operating temperature, when the network is fixed, dynamic covalent networks are elastic solids, while at high temperatures, chemical exchange reactions turn the network into a processible viscoelastic material. Upon heating a dissociative network, the viscosity may also decrease due to a shift of the chemical equilibrium; in such materials, the balance between processibility and excessive flow is important. In this study, a network is prepared that upon heating to above ≈110 °C dissociates to a significant extent due to a shift in the amide–imide equilibrium of a bisimide, pyromellitic diimide, in combination with poly(tetrahydrofuran) diamines. At room temperature, the resulting materials are elastic rubbers with a tensile modulus of 2–10 MPa, and they become predominantly viscous above a temperature of approximately 110 °C, which is dependent on the stoichiometry of the components. The diamide–imide equilibrium was studied in model reactions with NMR, and variable temperature infrared (IR) spectroscopy was used to investigate the temperature dependence of the equilibrium in the network. The temperature-dependent mechanical properties of the networks were found to be fully reversible, and the material could be reprocessed several times without loss of properties such as modulus or strain at break. The high processibility of these networks at elevated temperatures creates opportunities in additive manufacturing applications such as selective laser sintering.

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“…A recent development in DCN research is the use of neighboring group-assisted exchange reactions. − These reactions lead to relatively fast topological rearrangement via a dissociative mechanism without the aid of external catalysts. The rearrangement occurs through a high energy cyclic intermediate such that the equilibrium lies almost completely toward the associated state and thus the material shows vitrimer-like properties.…”

Section: Introductionmentioning

confidence: 99%

Efficient Exchange in a Bioinspired Dynamic Covalent Polymer Network via a Cyclic Phosphate Triester Intermediate

et al. 2021

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Bond exchange via neighboring group-assisted reactions in dynamic covalent networks results in efficient mechanical relaxation. In Nature, the high reactivity of RNA toward nucleophilic substitution is largely attributed to the formation of a cyclic phosphate ester intermediate via neighboring group participation. We took inspiration from RNA to develop a dynamic covalent network based on β-hydroxyl-mediated transesterifications of hydroxyethyl phosphate triesters. A simple one-step synthetic strategy provided a network containing phosphate triesters with a pendant hydroxyethyl group. 31 P solid-state NMR demonstrated that a cyclic phosphate triester is an intermediate in transesterification, leading to dissociative network rearrangement. Significant viscous flow at 60–100 °C makes the material suitable for fast processing via extrusion and compression molding.

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Neighboring Group Participation and Internal Catalysis Effects on Exchangeable Covalent Bonds: Application to the Thriving Field of Vitrimer Chemistry

Cited by 111 publications

References 261 publications

Fully Biobased Vitrimers: Future Direction toward Sustainable Cross‐Linked Polymers

Fully Biobased Vitrimers: Future Direction toward Sustainable Cross‐Linked Polymers

Dynamic Polyamide Networks via Amide–Imide Exchange

Efficient Exchange in a Bioinspired Dynamic Covalent Polymer Network via a Cyclic Phosphate Triester Intermediate

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