Transamidation vitrimers enabled by neighbouring fluorine atom activation

Berne, Dimitri; Tanguy, Gwendal; Caillol, Sylvain; Poli, Rinaldo; Ladmiral, Vincent; Leclerc, Eric

doi:10.1039/d3py00577a

Cited by 3 publications

(4 citation statements)

References 97 publications

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“…To date, multifarious exchangeable reactions have been utilized to prepare vitrimers, including transesterification, [29][30][31][32] disulfide exchange, [33][34][35] dynamic hindered urea exchange, [36][37][38] transurethanization, [39][40][41] boronic ester exchange, 42,43 siloxane exchange, 44 and transamidation. 45,46 Among them, the reversible transesterification and transurethanization are widely applied in the recycling and reprocessing of PUs. [39][40][41]47,48 To explore reprocessable polyurethanes with excellent flame retardancy and mechanical properties, we developed in this work vitrimeric poly(isocyanurate urethane) s (VPICUs) based on THEIC and dicarbamates (DCs).…”

Section: Introductionmentioning

confidence: 99%

Flame retarded polyurethane vitrimers containing isocyanurate rings: Synthesis and properties

Meng,

Yang,

Shen

et al. 2024

J of Applied Polymer Sci

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In this study, flame retarded polyurethane vitrimers, namely vitrimeric poly(isocyanurate urethane)s (VPICUs), were synthesized successfully by melting polycondensation simply from tris(2‐hydroxyethyl)isocyanurate and dicarbamates. By increasing the methylene number in dicarbamates from 4 to 10, the VPICUs exhibit superior mechanical performance with elongation at break increases from 20% to 350% while the tensile strength decreases from 80 to 32 MPa, and the toughness can be significantly enhanced from 9 to 90 J/cm3. With a mass fraction of isocyanurate ring at 26.6%, for VPICU10‐2.5/2, the flame retardancy is found to be the most excellent, with a UL‐94 rating at V‐0 and a LOI value at 25.9%. VPICU10 samples exhibit substantial relaxation behavior at higher temperature, and the network rearrangement activated by transesterification and transurethanization reactions offers the reprocessability without losing the properties. This work provides new insights into the construction of sustainable and high‐performance flame retarded polymer materials.

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Section: Introductionmentioning

confidence: 99%

Flame retarded polyurethane vitrimers containing isocyanurate rings: Synthesis and properties

Meng,

Yang,

Shen

et al. 2024

J of Applied Polymer Sci

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“…In-depth studies combining kinetics and density functional theory (DFT) calculations highlighted the specific activation by fluorine on transesterification 63,64 and transamidation 65 and quantified its impact on the activation energy of the respective exchange reaction. 65,71 Finally, fluorine activation of the recently introduced aza-Michael exchange enabled to drastically decrease the reprocessing temperature of these CANs. 66 However, if the fluorine activating effect on this series of exchange reaction has been clearly demonstrated, our previously reported thia-Michael thermosets exhibited no dynamic properties in the absence of any internal or external base, despite the presence of a CF 3 group.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In the past few years, our group has evidenced the significant activating effect of fluorine for the synthesis of a range of polymer networks. In particular, thanks to its high electronegativity, epoxy/acid, , amidation, and Michael additions (including the aza and thia versions) − have been shown to be strongly accelerated by proximal fluorine atom substitution. Moreover, fluorine activation not only enables the fast synthesis of these networks but also promotes a series of exchange reactions.…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, the use of α-difluorinated ,, or α-CF 3 esters enables the reprocessability of catalyst-free transesterification vitrimers. In-depth studies combining kinetics and density functional theory (DFT) calculations highlighted the specific activation by fluorine on transesterification , and transamidation and quantified its impact on the activation energy of the respective exchange reaction. , Finally, fluorine activation of the recently introduced aza-Michael exchange enabled to drastically decrease the reprocessing temperature of these CANs …”

Section: Introductionmentioning

confidence: 99%

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Combination of Fluorine and Tertiary Amine Activation in Catalyst-Free Thia-Michael Covalent Adaptable Networks

Berne,

Poli,

Caillol

et al. 2023

Macromolecules

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A series of catalyst-free covalent adaptable networks (CANs) have been developed using a reversible thia-Michael reaction activated by fluorine atom substitution and by an intramolecular tertiary amine. The thia-Michael exchange rate was first evaluated by a preliminary molecular study coupled to density functional theory (DFT) calculations. This study enabled us to highlight the necessity of combining fluorine and tertiary amine activation to observe the thia-Michael exchange. Then, by modulating the structure, nature, and functionality of the thiol monomers, a wide range of mechanical properties and thermal properties were achieved. Relationships between the monomer structure and the dynamic properties were also highlighted through the dynamic study of these materials. Finally, the ability of the fluorinated thia-Michael CANs to be reprocessed was assessed by thermal and mechanical analyses of up to three reshaping cycles.

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Trifluoromethylated N,S-Acetal as a Chemical Platform for Covalent Adaptable Networks: Fast Thiol Exchange and Strong Hydrostability for a Highly Transparent Material

Laviéville,

Totée,

Guiffrey

et al. 2024

Macromolecules

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This work presents the synthesis and characterization of a highly transparent and colorless covalent adaptable network (CAN) exhibiting short relaxation times (30 s at 150 °C) and limited creep at 100 °C. Based on N,S-acetal functions, strongly stabilized by a trifluoromethyl group, this network, however, retains the ability to undergo fast thiol exchanges. The present article describes a detailed monitoring of the cross-linking via ATR-FTIR and 19 F HRMAS NMR (high-resolution magic angle spinning NMR), the complete structural characterization of the material via 13 C HRMAS NMR, and the comprehensive study of the rheological properties of this novel N,S-acetal network. This CAN shows hydrolytic stability and higher activation energies (>90 kJ mol −1 ) than its nonfluorinated counterparts. Its reprocessing occurs under relatively mild conditions without the need for a catalyst, and depolymerization can be achieved either with an amine (benzylamine), under acidic conditions (1 M HCl) at room temperature, or with a thiol (1-dodecanethiol) at 100 °C.

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Transamidation vitrimers enabled by neighbouring fluorine atom activation

Abstract: The activation of associative transamidation via neighboring fluorine atom activation has been unveiled, quantified and applied for the construction of catalyst-free polyamide vitrimers. While the poorly reactive amide functionality is...

Cited by 3 publications

References 97 publications

Flame retarded polyurethane vitrimers containing isocyanurate rings: Synthesis and properties

Flame retarded polyurethane vitrimers containing isocyanurate rings: Synthesis and properties

Combination of Fluorine and Tertiary Amine Activation in Catalyst-Free Thia-Michael Covalent Adaptable Networks

Trifluoromethylated N,S-Acetal as a Chemical Platform for Covalent Adaptable Networks: Fast Thiol Exchange and Strong Hydrostability for a Highly Transparent Material

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