Achievement of a Highly Rapid Bond Exchange for Self-Catalyzed Polyester Vitrimers by Incorporating Tertiary Amino Groups on the Network Strands

Hayashi, Mikihiro; Inaba, Takaya

doi:10.1021/acsapm.1c00724

Cited by 19 publications

(21 citation statements)

References 30 publications

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“…The observed T soft was in line with the values reported for other vitrimers operated with transesterification. 31,34,56,57 For clearer comparison, Figure 4b plots the deviation degree of the experimental curve from the approximated linear line (ΔL exp-linear ) as a function of temperatures. The plateau of ΔL exp-linear below T soft is simply related to the variation of thermal expansion with an increase in temperature, and the result of ΔL exp-linear ∼ 0 with no dependence of f is reasonable.…”

Section: ■ Resultsmentioning

confidence: 99%

Critical Effects of Branch Numbers at the Cross-Link Point on the Relaxation Behaviors of Transesterification Vitrimers

Isogai

Hayashi

2022

Macromolecules

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Vitrimers are functional cross-linked materials, exhibiting reprocessability, recyclability, and healability, and thus these are expected for application as sustainable materials. The functionalities of vitrimers are attributable to their associative bond exchange mechanism that is activated at a certain high temperature. The construction of a tuning method for the bond exchange properties must be useful for coming practical application of the vitrimer concept. Here, we prepare transesterification-based vitrimers via the thiol−epoxy click reaction to elucidate the essential effects of the branch numbers (f) at the cross-link point on their bond exchange properties, where f can be readily tuned via the functionality of the starting materials. The temperature-ramp creep and stress−relaxation tests then demonstrate that the vitrimer properties, such as the softening and stress−relaxation behaviors, vary depending on f. The experimental results derive some empirical relationships between f and the relaxation time and between f and activation energy of the bond exchange. In addition, the relaxation behavior of the vitrimer network with mixed f is investigated in the final section, showing the relaxation rate can be determined by the harmonic mean of relaxation time weighted by the mole fraction of the network components having different f. Overall, this study demonstrates that the design of a proper f is crucial to obtain the desired properties of vitrimers.

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Section: ■ Resultsmentioning

confidence: 99%

Critical Effects of Branch Numbers at the Cross-Link Point on the Relaxation Behaviors of Transesterification Vitrimers

Isogai

Hayashi

2022

Macromolecules

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“…To assess the difference in the bond exchange rate, we estimated the characteristic relaxation time (τ*) based on the Kohlrausch–Williams–Watts (KWW) model . Dissimilar to the simple Maxwell model, the KWW model considered the distribution of the relaxation time using the stretched exponential function with a coefficient β, which is known to be appropriate to describe the relaxation behavior of vitrimers or vitrimer-like materials. , …”

Section: Resultsmentioning

confidence: 99%

“…52 Dissimilar to the simple Maxwell model, the KWW model considered the distribution of the relaxation time using the stretched exponential function with a coefficient β, which is known to be appropriate to describe the relaxation behavior of vitrimers or vitrimer-like materials. 53,54 t t ( ) exp ( )…”

Section: ■ Resultsmentioning

confidence: 99%

Correlation between Self-Assembled Nanostructures and Bond Exchange Properties for Polyacrylate-Based Vitrimer-like Materials with a Trans-N-Alkylation Bond Exchange Mechanism

et al. 2022

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To solve the problem of conventional cross-linked materials with permanent cross-links such as the lack of recyclability and reprocessability, a new type of cross-linked material with exchangeable covalent bonds, called vitrimers, has attracted great attention. Although various kinds of polymeric frameworks with compatible exchange reactions have been reported to date, the designs with self-assembled nanostructures remain limited. In this study, we assessed the correlation of self-assembled structures on bond exchange properties for vitrimer-like materials, which were prepared via the pyridine-bromo quaternization of polyacrylate-based random copolymers bearing pyridine side groups. Small-angle X-ray scattering revealed that the quaternized pyridines formed nanoscale aggregations, and the features of the aggregates varied with the length of alkyl side groups of the component polyacrylates. Interestingly, the small change in the length of the alkyl side groups affected the aggregation size, which eventually provided the difference in relaxation rate. This study demonstrated a new methodology for tuning the bond exchange properties and provided important knowledge for analyzing the physical properties of vitrimer or vitrimer-like materials with self-assembled structures.

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“…[190] The most common approach for catalyzed NGP on CANs relies on the presence of nucleophilic or basic vicinal atoms, such as sulfur, [191] oxygen, [192][193][194][195][196][197][198][199] and nitrogen. [200][201][202][203][204] The discovery of CANs and vitrimers opened the field for self-healable and smart materials, addressing the need for reprocessing and recycling of "plastics". Organocatalyzed reforming not only offers good performances but also allows the preparation of bio-related materials, lowering the [185] b) Bistable light-mediated phase switching of thiol-thioester exchange in the presence of a base.…”

Section: Accelerating the On-demand Dynamic Covalent Bond Exchangementioning

confidence: 99%

“…In contrast to external catalysis, this rational approach aims to mimic the sophisticated enzymatic processes in nature [190] . The most common approach for catalyzed NGP on CANs relies on the presence of nucleophilic or basic vicinal atoms, such as sulfur, [191] oxygen, [192–199] and nitrogen [200–204] …”

Section: Burgeoning Areas In Organocatalyzed and Other Transition‐met...mentioning

confidence: 99%

Spotting Trends in Organocatalyzed and Other Organomediated (De)polymerizations and Polymer Functionalizations

et al. 2022

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Organocatalysis has evolved into an effective complement to metal-or enzyme-based catalysis in polymerization, polymer functionalization, and depolymerization. The ease of removal and greater sustainability of organocatalysts relative to transition-metal-based ones has spurred development in specialty applications, e.g., medical devices, drug delivery, optoelectronics. Despite this, the use of organocatalysis and other organomediated reactions in polymer chemistry is still rapidly developing, and we envisage their rapidly growing application in nascent areas such as controlled radical polymerization, additive manufacturing, and chemical recycling in the coming years. In this Review, we describe ten trending areas where we anticipate paradigm shifts resulting from novel organocatalysts and other transition-metalfree conditions. We highlight opportunities and challenges and detail how new discoveries could lead to previously inaccessible functional materials and a potentially circular plastics economy.

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Achievement of a Highly Rapid Bond Exchange for Self-Catalyzed Polyester Vitrimers by Incorporating Tertiary Amino Groups on the Network Strands

Cited by 19 publications

References 30 publications

Critical Effects of Branch Numbers at the Cross-Link Point on the Relaxation Behaviors of Transesterification Vitrimers

Critical Effects of Branch Numbers at the Cross-Link Point on the Relaxation Behaviors of Transesterification Vitrimers

Correlation between Self-Assembled Nanostructures and Bond Exchange Properties for Polyacrylate-Based Vitrimer-like Materials with a Trans-N-Alkylation Bond Exchange Mechanism

Spotting Trends in Organocatalyzed and Other Organomediated (De)polymerizations and Polymer Functionalizations

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