Thermosets based on reversible covalent bonds (Vitrimers)

Jarach, Natanel; Golani, D.; Dodiuk, H.; Naveh, Naum; Kenig, S.

doi:10.1016/b978-0-12-821632-3.00023-3

Cited by 6 publications

(10 citation statements)

References 158 publications

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“…Reversible covalent-bond-containing polymers (RCBPs), also known as vitrimers, covalent adaptable networks (CANs), or reorganizable polymers, are a new class of polymers that share a three-dimensional (3D) network-like structure with thermosets while having reprocessability and recyclability due to their dynamic or reversible cross-links. − Among the reversible bonds studied in the literature, [2 + 2] and [4 + 4] cycloadditions are unique in having potential use in irradiation-based applications, such as photocuring of adhesives and stereolithography-based 3D printing. This potential results from the adduct formation under irradiation at specific wavelengths and dissociation under shorter ones . Unlike any other radiation-curing mechanisms, the complete dissociation of the adducts into their original components holds their potential for recyclability, followed by re-using in irradiation-based applications.…”

Section: Introductionmentioning

confidence: 99%

“…This potential results from the adduct formation under irradiation at specific wavelengths and dissociation under shorter ones. 1 Unlike any other radiation-curing mechanisms, the complete dissociation of the adducts into their original components holds their potential for recyclability, followed by re-using in irradiation-based applications. Several such materials have been demonstrated in the literature.…”

Section: Introductionmentioning

confidence: 99%

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Tetra-Dentate Cycloaddition Catalysts for Rapid Photopolymerization Reactions

et al. 2023

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Metrics & MoreArticle Recommendations * sı Supporting InformationABSTRACT: [4 + 4] and [2 + 2] cycloadditions are unique reactions since they form and deform cycloadducts under irradiation due to their inherent reversible nature. Whereas promising for the field of recycling, these reactions usually suffer from two major shortcomings: long reaction durations (hours) and the requirement of high-intensity light (∼100 W/cm 2 ), typically at a short wavelength (<330 nm). We demonstrate several tetra-dentate catalysts that can overcome these fundamental limitations. Among them is a tin complex that enables 76% conversion within only 2 min of irradiation at 395 nm, much faster than the known ruthenium-based catalyst, under irradiation with light intensity two orders of magnitude lower than that reported in the literature. Due to the short photopolymerization time, low intensity (27 mW/cm 2 ), and long UV light (395 nm), this unique complex opens new avenues for recycling three-dimensional printing products based on photopolymerization of cycloaddition reactions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tetra-Dentate Cycloaddition Catalysts for Rapid Photopolymerization Reactions

et al. 2023

Self Cite

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“…Such materials incorporate dynamic and reversible bonds; thus, they can be processed despite their network structure composed of cross-linked polymers (thermosets). [1][2][3] In general, RCBPs are divided into two types of bonds: dynamic bonds, also known as associative CANs, and general bonds, also known as dissociative CANs. [1] Dynamic bonds, like the thermal-triggered transesterification of 𝛽-hydroxy esters, react to a similar factor to form or break the bonds.…”

Section: Introductionmentioning

confidence: 99%

“…While polymers offer advantages such as high volume‐to‐weight and strength‐to‐weight ratios, existing recycling methods often result in degraded properties, highlighting the need for better sustainable solutions. [ 1,2 ] Recent approaches for addressing the recycling of plastics involve Reversible Covalent Bonds Containing Polymers (RCBPs), also known as Covalent Adaptable Networks (CANs) or vitrimers. Such materials incorporate dynamic and reversible bonds; thus, they can be processed despite their network structure composed of cross‐linked polymers (thermosets).…”

Section: Introductionmentioning

confidence: 99%

Fully Recyclable Cured Polymers for Sustainable 3D Printing

Jarach,

Dodiuk,

Kenig

et al. 2023

Advanced Materials

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The most prevalent materials used in the Additive Manufacturing era are polymers and plastics. Unfortunately, these materials are recognized for their negative environmental impact as they are primarily non‐recyclable, resulting in environmental pollution. In recent years, a new sustainable alternative to these materials has been emerging: reversible covalent bond‐containing polymers (RCBPs). These materials can be recycled, reprocessed, and reused multiple times without losing their properties. Nonetheless, they have two significant drawbacks when used in 3D printing. First, some require adding new materials every reprinting cycle, and second, others require high temperatures for (re)printing, limiting recyclability and increasing energy consumption. This study, thus, introduces fully recyclable RCBPs as a sustainable approach for radiation‐based printing technologies. This approach enables multiple (re)printing cycles at low temperatures (50 °C lower than the lowest reported) without adding new materials. It involves purposefully synthesized polymers that undergo reversible photopolymerization, composed of a tin‐based catalyst. An everyday microwave oven quickly de‐polymerized these polymers, obtaining complete reversibility.This article is protected by copyright. All rights reserved

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“…Under this circumstance, vitrimers can flow like vitreous fluid [ 14 , 15 ]. The exchangeable networks enable epoxy vitrimers to be recycled, reshaped and reprocessed at a high temperature [ 16 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Epoxy/Acid Stoichiometry on the Cure Behavior and Mechanical Properties of Epoxy Vitrimers

Fan

Zhao

et al. 2022

Molecules

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Bisphenol A epoxy resin cured with a mixture of dimerized and trimerized fatty acids is the first epoxy vitrimer and has been extensively studied. However, the cure behavior and thermal and mechanical properties of this epoxy vitrimer depend on the epoxy/acid stoichiometry. To address these issues, epoxy vitrimers with three epoxy/acid stoichiometries (9:11, 1:1 and 11:9) were prepared and recycled four times. Differential scanning calorimetry (DSC) was used to study the cure behavior of the original epoxy vitrimers. The dynamic mechanical properties and mechanical performance of the original and recycled epoxy vitrimers were investigated by using dynamic mechanical analysis (DMA) and a universal testing machine. Furthermore, the reaction mechanism of epoxy vitrimer with different epoxy/acid stoichiometry was interpreted. With an increase in the epoxy/acid ratio, the reaction rate, swelling ratio, glass transition temperature and mechanical properties of the original epoxy vitrimers decreased, whereas the gel content increased. The recycling decreased the swelling ratio and elongation at break of the original epoxy vitrimers. Moreover, the elongation at break of the recycled epoxy vitrimers decreased with the epoxy/acid ratio at the same recycling time. However, the gel content, tensile strength and toughness of the original epoxy vitrimers increased after the recycling. The mechanical properties of epoxy vitrimers can be tuned with the variation in the epoxy/acid stoichiometry.

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Thermosets based on reversible covalent bonds (Vitrimers)

Cited by 6 publications

References 158 publications

Tetra-Dentate Cycloaddition Catalysts for Rapid Photopolymerization Reactions

Tetra-Dentate Cycloaddition Catalysts for Rapid Photopolymerization Reactions

Fully Recyclable Cured Polymers for Sustainable 3D Printing

Influence of the Epoxy/Acid Stoichiometry on the Cure Behavior and Mechanical Properties of Epoxy Vitrimers

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