Dynamic covalent chemistry in polymer networks: a mechanistic perspective

Winne, Johan M.; Leibler, Ludwik; Prez, Filip Du

doi:10.1039/c9py01260e

Cited by 509 publications

(616 citation statements)

References 89 publications

Supporting

Mentioning

610

Contrasting

Unclassified

Order By: Relevance

“…Similarly,the difference in T g couldalso explainthe discrepancy in ther ankingo fCAN-7,8,9,w here theh igh T g of CAN-9 indicates ar estrictedm obility,r esulting in as lower relaxation time compared to CAN-7,8.T heseo bservations highlighted again thef act that exchange on am aterial level is not only controlledb yt he kinetics of dynamic bond exchange, butw ill also be substantiallyi nfluenced by matrix effects,t hata re not capturedb ys mall molecule models. [3] It is importantt onote that in thea bsence of an associative bond exchangem echanism, thep repared CANsc annot be classified as vitrimers,despite theobserved linear relationshipof relaxation timesa nd temperature in theA rrheniusp lots (Figure 4c). To illustratethe dissociative bond exchange mechanism operating in dynamict hiol-yne networks,f requencys weep measurementsw ere performed at different temperatures.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…Covalent adaptable networks (CANs) are polymer materials that combine the strength of covalently cross-linked materials,s uch as high chemical resistance and dimensional stability,w ith the reprocessability of thermoplastic polymers. [1][2][3][4] These responsive polymer networks have the ability to reversibly rearrange their network topology through the action of dynamic exchanges.Upon application of an external stimulus (such as heat, light), the dynamic chemistry is activated to allow bond exchanges on amolecular level, which enables network plasticity and allows reshaping,reprocessing, stress relaxation, self-healing, and imprinting.…”

Section: Introductionmentioning

confidence: 99%

“…An important characteristic of CANs is the underlying bond exchange mechanism as it ultimately determines the mechanical properties of aC AN during the applied stimulus. [3] Reversible polymer networks or so-called dissociative CANs imply that abond-breaking event happens prior to the formation of an ew bond (that is,a ne limination-addition mechanism), whereas bond exchange in permanent dynamic networks,a lso called vitrimers or associative CANs,i s achieved through ab ond-forming/bond-breaking sequence (an addition-elimination reaction). [1,5] As ar esult, dissociative CANs can show at emporary decrease in network connectivity during the stimulus application, which may result in as udden decrease of viscosity,w hile associative CANs or vitrimers,p reserve their network integrity in all conditions and do not undergo ag el-to-sol transition.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Covalent Adaptable Networks with Tunable Exchange Rates Based on Reversible Thiol–yne Cross‐Linking

et al. 2020

Self Cite

View full text Add to dashboard Cite

The design of covalent adaptable networks (CANs) relies on the ability to trigger the rearrangement of bonds within a polymer network. Simple activated alkynes are now used as versatile reversible cross‐linkers for thiols. The click‐like thiol–yne cross‐linking reaction readily enables network synthesis from polythiols through a double Michael addition with a reversible and tunable second addition step. The resulting thioacetal cross‐linking moieties are robust but dynamic linkages. A series of different activated alkynes have been synthesized and systematically probed for their ability to produce dynamic thioacetal linkages, both in kinetic studies of small molecule models, as well as in stress relaxation and creep measurements on thiol–yne‐based CANs. The results are further rationalized by DFT calculations, showing that the bond exchange rates can be significantly influenced by the choice of the activated alkyne cross‐linker.

show abstract

Section: Angewandte Chemiementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Covalent Adaptable Networks with Tunable Exchange Rates Based on Reversible Thiol–yne Cross‐Linking

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Stimuli-responsive, self-assembled or selfhealing polymers are examples of "smart" materials, [53][54][55] going beyond the possibilities of traditional ones in approaching those of living matter. These "smart" materials could be enabled by dynamic covalent networks to provide adaptive/ sensing materials, [56][57][58][59][60] or vitrimers, [61,62] an interesting new class of plastically deformable covalent organic networks, which were inspired by work performed by Stadler on thermoplastic elastomers. [63] Vitrimers have properties of a thermoset but flow like viscous liquids at higher temperatures.…”

Section: Where May the Discipline Go In The Next 20-30 Years? What Armentioning

confidence: 99%

Quo Vadis, Macromolecular Science? Reflections by the IUPAC Polymer Division on the Occasion of the Staudinger Centenary

Abetz¹,

Chan

Luscombe

et al. 2020

Israel Journal of Chemistry

View full text Add to dashboard Cite

We survey the past, present and future of polymers and macromolecular science, both in general and giving specific examples from our diverse array of research backgrounds within polymer science and technology. As befitting our common bond, we pay some attention to the role of IUPAC. In line with this being part of a Rosarium philosophorum, one might say we conclude that it is Citius, Altius, Fortius for polymers in the century ahead, by which we mean “faster engagement, higher value, stronger properties”, and one should also add “longer usage”. In this way our broad community will continue to build on the century that has passed since Hermann Staudinger launched macromolecular science.

show abstract

“…47,48,49,50,51 Recent reviews have summarized this progress in developing vitrimer chemistry, materials, and applications. 52,53,54,55 The dynamic characteristics of vitrimers are often enabled by incorporating functional groups into homopolymer networks. The polarizability of the functional groups can be much different from the network monomers.…”

Section: Introductionmentioning

confidence: 99%

Linear Viscoelasticity and Flow of Self-Assembled Vitrimers: The Case of a Polyethylene/dioxaborolane System

Ricarte

Tournilhac²,

Cloître³

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

For vitrimer systems obtained by dynamic cross-linking of polymer chains, incompatibility effects between the cross-links and polymer backbone can lead to microphase separation, resulting in a network made of cross-linked aggregates. Additionally, when there is a wide distribution of the number of cross-links per chain, macrophase separation can occur. Here, we investigate the linear viscoelasticity and flow of a polyethylene (PE) vitrimer that has cross-linkable dioxaborolane maleimide grafts, which aggregate into a hierarchical nanostructure. To elucidate the role of selfassembly, noncross-linked graft functionalized PE was first studied. It had a terminal relaxation time that was orders of magnitude larger than both neat PE and partially peroxide cross-linked PE.When dioxaborolane cross-linker was added to form the vitrimer, the resulting material could not achieve terminal relaxation within 8 hr. The graft-poor soluble and graft-rich insoluble portions of the PE vitrimer were then isolated and characterized. The soluble portion expressed similar flow behavior as neat PE, while the insoluble portion -which is a network of cross-linked aggregatesrelaxed very little over 8 hr. When the insoluble and soluble portions were blended, the rheological behavior of the original vitrimer was basically recovered, showing that the soluble portion acts as a lubricant. When the insoluble portion was blended with neat PE, the material relaxed much more stress, but still did not reach steady-state flow within 8 hr. When high stresses were applied, however, PE vitrimer flowed. Nonlinear rheology experiments revealed melt fracture at high strains and suggested that flow is enabled by rapid healing, which follows fracture events. The presence of macroscopic phase separation facilitated flow.

show abstract

Dynamic covalent chemistry in polymer networks: a mechanistic perspective

Abstract: A selection of dynamic chemistries is highlighted, with a focus on the reaction mechanisms of molecular network rearrangements, and on how mechanistic profiles can be related to the mechanical and physicochemical properties of polymer materials.

Cited by 509 publications

References 89 publications

Covalent Adaptable Networks with Tunable Exchange Rates Based on Reversible Thiol–yne Cross‐Linking

Covalent Adaptable Networks with Tunable Exchange Rates Based on Reversible Thiol–yne Cross‐Linking

Quo Vadis, Macromolecular Science? Reflections by the IUPAC Polymer Division on the Occasion of the Staudinger Centenary

Linear Viscoelasticity and Flow of Self-Assembled Vitrimers: The Case of a Polyethylene/dioxaborolane System

Contact Info

Product

Resources

About