Time-Temperature-Transformation, Temperature-Conversion-Transformation, and Continuous-Heating-Transformation Diagrams of Reversible Covalent Polymer Networks

Mangialetto, Jessica; Verhelle, Robrecht René; Assche, Guy Van; Brande, Niko Van den; Mele, Bruno Van

doi:10.1021/acs.macromol.0c02491

Cited by 23 publications

(49 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At the same time, recent kinetic studies on the stereochemistry of the furan/maleimide DA reaction reveal that the endo -isomer has a lower activation energy value than the exo -isomer [ 49 , 50 , 51 ].…”

Section: Resultsmentioning

confidence: 99%

Chitosan Hydrogels Based on the Diels–Alder Click Reaction: Rheological and Kinetic Study

et al. 2022

View full text Add to dashboard Cite

The Diels–Alder reaction is recognized to generate highly selective and regiospecific cycloadducts. In this study, we carried out a rheological and kinetic study of N-furfuryl chitosan hydrogels based on the Diels–Alder click reaction with different poly(ethylene)glycol-maleimide derivatives in dilute aqueous acidic solutions. It was possible to prepare clear and transparent hydrogels with excellent mechanical properties. Applying the Winter and Chambon criterion the gel times were estimated at different temperatures, and the activation energy was calculated. The higher the temperature of gelation, the higher the reaction rate. The crosslinking density and the elastic properties seem to be controlled by the diffusion of the polymer segments, rather than by the kinetics of the reaction. An increase in the concentration of any of the two functional groups is accompanied by a higher crosslinking density regardless maleimide:furan molar ratio. The hydrogel showed an improvement in their mechanical properties as the temperature increases up to 70 °C. Above that, there is a drop in G’ values indicating that there is a process opposing to the Diels–Alder reaction, most likely the retro-Diels–Alder.

show abstract

Section: Resultsmentioning

confidence: 99%

Chitosan Hydrogels Based on the Diels–Alder Click Reaction: Rheological and Kinetic Study

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The furan and maleimide compounds used to measure the initial Diels–Alder reaction rates at 20 °C are depicted in Figure 2 . Their nomenclature and synthesis are described in [ 9 , 11 ]. The synthesis of the modified 4F400-ester (OH free) is described in the Supplementary Materials .…”

Section: Methodsmentioning

confidence: 99%

“…Diels–Alder (DA) cycloadditions based on furan-maleimide chemistry, with formation of endo and exo stereoisomers according to two equilibria (see Figure 1 ), are important for developing reversible polymer networks by the introduction of reversible covalent bonds in the polymer backbone (indicated by arrows in Figure 1 ) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the kinetics and thermodynamics were experimentally determined for a series of reversible model networks of which the glass transition temperature and thermomechanical properties could be altered by varying the spacer length between the furan and maleimide DA reagents (see R 1 and R 2 flexible side groups in Figure 1 ) [ 8 , 9 , 11 ]. A mechanistic model as shown in Figure 1 was used, considering the equilibrium reactions between the furan and maleimide functional groups and the endo and exo DA cycloadducts.…”

Section: Introductionmentioning

confidence: 99%

“…A mechanistic model as shown in Figure 1 was used, considering the equilibrium reactions between the furan and maleimide functional groups and the endo and exo DA cycloadducts. The main experimental kinetic and thermodynamic conclusions were [ 8 , 11 ]:…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hydrogen-Bond-Assisted Diels–Alder Kinetics or Self-Healing in Reversible Polymer Networks? A Combined Experimental and Theoretical Study

et al. 2022

Self Cite

View full text Add to dashboard Cite

Diels–Alder (DA) cycloadditions in reversible polymer networks are important for designing sustainable materials with self-healing properties. In this study, the DA kinetics of hydroxyl-substituted bis- and tetrafunctional furans with bis- and tris-functional maleimides, both containing ether-functionalized spacers, is investigated by modelling two equilibria representing the endo and exo cycloadduct formation. Concretely, the potential catalysis of the DA reaction through hydrogen bonding between hydroxyl of the furans and carbonyl of the maleimides or ether of the spacers is experimentally and theoretically scrutinized. Initial reaction rates and forward DA rate constants are determined by microcalorimetry at 20 °C for a model series of reversible networks, extended with (i) a hydroxyl-free network and hydroxyl-free linear or branched systems, and (ii) polypropylene glycol additives, increasing the hydroxyl concentration. A computational density-functional theory study is carried out on the endo and exo cycloadditions of furan and maleimide derivatives, representative for the experimental ones, in the absence and presence of ethylene glycol as additive. Additionally, an ester-substituted furan was investigated as a hydroxyl-free system for comparison. Experiment and theory indicate that the catalytic effect of H-bonding is absent or very limited. While increased concentration of H-bonding could in theory catalyze the DA reaction, the experimental results rule out this supposition.

show abstract

Designing End‐of‐Life Recyclable Polymers via Diels–Alder Chemistry: A Review on the Kinetics of Reversible Reactions

Tempel

Picchioni

Bose

2022

Macromol. Rapid Commun.

View full text Add to dashboard Cite

The purpose of this review is to critically assess the kinetic behavior of the furan/maleimide Diels-Alder click reaction. The popularity of this reaction is evident and still continues to grow, which is likely attributed to its reversibility at temperatures above 100 °C, and due to its biobased "roots" in terms of raw materials. This chemistry is used to form thermoreversible crosslinks in polymer networks, and thus allows the polymer field to design strong, but also end-of-life recyclable thermosets and rubbers. In this context, the rate at which the forward reaction (Diels-Alder for crosslinking) and its reverse (retro Diels-Alder for decrosslinking) proceed as a function of temperature is of crucial importance in assessing the feasibility of the design in real-life products. Differences in kinetics based from various studies are not well understood, but are potentially caused by chemical side groups, mass transfer limitations, and the analysis methods being employed. In this work, all the relevant studies are attempted to be placed in perspective with respect to each other, and thereby offer a general guide is offered on how to assess their recycling kinetics.

show abstract

Time-Temperature-Transformation, Temperature-Conversion-Transformation, and Continuous-Heating-Transformation Diagrams of Reversible Covalent Polymer Networks

Cited by 23 publications

References 46 publications

Chitosan Hydrogels Based on the Diels–Alder Click Reaction: Rheological and Kinetic Study

Chitosan Hydrogels Based on the Diels–Alder Click Reaction: Rheological and Kinetic Study

Hydrogen-Bond-Assisted Diels–Alder Kinetics or Self-Healing in Reversible Polymer Networks? A Combined Experimental and Theoretical Study

Designing End‐of‐Life Recyclable Polymers via Diels–Alder Chemistry: A Review on the Kinetics of Reversible Reactions

Contact Info

Product

Resources

About