Learning from the trees: biomimetic crosslinking of silicones by phenolic coupling

Li, A.; Meléndez-Zamudio, Miguel; Yepremyan, Akop; Brook, Michael A.

doi:10.1039/d3gc01282d

Cited by 3 publications

(3 citation statements)

References 32 publications

(55 reference statements)

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“…4C). 37 That is, coupling can occur as a consequence of their antioxidant capacity. The resulting elastomers maintain antioxidant properties that are only slightly attenuated when compared to 2 .…”

Section: Using Traditional Processes To Develop New Functionalitymentioning

confidence: 99%

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Functional silicone oils and elastomers: new routes lead to new properties

Brook

2023

Chem. Commun.

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Section: Using Traditional Processes To Develop New Functionalitymentioning

confidence: 99%

“…29 (C) Crosslinking using oxidative phenolic coupling. 37 (D) and (E) Sequential crosslinking with up to 3 different types of silicones to generate silicone foams (note: performing the PR reactions first and hydrosilylation last leads to elastomers rather than foams). 38 6.1.2.1 Surfactants.…”

Section: Click Reactions With Catalystsmentioning

confidence: 99%

Functional silicone oils and elastomers: new routes lead to new properties

Brook

2023

Chem. Commun.

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“…Eugenol has many reactive sites such as allyl, methoxyl, phenolic hydroxyl, and activated aromatic hydrogens, making it a good candidate for organic and polymer synthesis. , Especially, eugenol has been converted into a number of epoxy prepolymers having one, , two, − three and more − eugenol-derived blocks. In addition, several silicon-functionalized eugenol-based epoxy thermosetting systems are formulated by incorporating eugenol-functionalized polydimethylsiloxane, , trimethylsilanized eugenol glycidyl ether, , linear siloxane-bridged eugenol diglycidyl ether, − cyclic siloxane-connected eugenol-derived polyglycidyl ethers, − MQ-functionalized eugenol-based diglycidyl ethers, , POSS-functionalized eugenol diglycidyl ethers, , etc. However, only limited reports have addressed eugenol-based phenolic resins so far.…”

Section: Introductionmentioning

confidence: 99%

Siloxane-Functionalized Eugenol-Based Novolacs: from Facile Synthesis to Their Cured Bisphenol A Epoxy Thermosets with Superb Toughness and Thermal Stability

Li,

Duan,

et al. 2024

ACS Appl. Polym. Mater.

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Conventional bisphenol A (BPA) epoxy resins suffer from intrinsic brittleness and inferior toughness after being transformed into a highly cross-linked network by a curative, and almost all epoxy curatives are from nonrenewable petrochemicals. Here, a series of siloxane-functionalized eugenol-based novolacs is synthesized and applied as the curative and toughener for a standard BPA epoxy (E54). Eugenol and 1,1,3,3-tetramethyldisiloane are connected through hydrosilylation to yield a bisphenol (2SiEU), followed by acid-catalyzed copolycondensation with paraformaldehyde (F) in acetic acid according to the varied molar ratios of F to 2SiEU (X = 0.5, 0.6, 0.7, or 0.8) to afford the novolacs (2SiEUPF-X). As X increases, the aromatic hydrogens (Ph−H) of 2SiEU substituted by carbons (Ph−C) increases with increased viscosities and molecular weights of 2SiEUPF-X. Both the hydroxyl and the methoxyl on 2SiEU moieties could activate the ortho positions on the aromatic rings to facilitate carbocation attack. 2SiEUPF-X has good thermal stability (T d5% > 330 °C) and fluidity at 100 °C (<2 Pa•s). 2SiEUPF-X is able to cross-link E54 well, and T g of the resultant 2SiEUPF-X/E54 thermosets increases from 60.5 to 73.7 °C as X increases. The thermosets exhibit superior thermal stability (T d5% > 430 °C, N 2 ), moderate tensile (47−49 MPa) and flexural (78−90 MPa) strengths, good stiffness at room temperature, and low moisture absorption in boiling water (<2%). Furthermore, the thermosets display significantly enhanced fracture toughness (K IC ), fracture energy (G IC ), and V-notched Charpy impact strength of 2.9−3.2 MPa•m 1/2 , 3.4−4.9 kJ•m −2 , and 5.6−6.5 kJ•m −2 , respectively. Altogether, 2SiEUPF-X is readily accessible and endows the cured BPA epoxy thermosets with superb toughness and thermal stability, playing a role in advancing biobased epoxy chemistry and technology.

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Phytochemicals from Bark Extracts and Their Applicability in the Synthesis of Thermosetting Polymers: An Overview

Szmechtyk,

Małecka

2024

Materials

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This review focuses on recent research on the phytochemicals found in bark from different trees and their potential to be used as substrates for the synthesis of thermosetting resins. Recent studies about the influence of each bark harvesting step on the extracted phytochemicals, from debarking to extraction, are investigated. A comparison of bark extracts in terms of the correlation between extraction conditions and efficiency (based on the total phenolic content (TPC) and extraction yield) is presented for six groups of trees (Norway spruce, pine species, other conifers, oak species, other deciduous trees of the north temperate zone, tropical and subtropical trees) and evaluated. The evaluation revealed that there is an interesting relationship between the extraction time and the type of solvent for some types of tree bark. It was found that a relatively short extraction time and a solvent temperature close to the boiling point are favourable. The latest research on the application of bark extracts in different types of thermosetting resins is described. This review discusses the attractiveness of bark extracts in terms of functional groups and the possibilities arising from extractable phytochemicals. In addition, different approaches (selective versus holistic) and methods of application are presented and compared.

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Learning from the trees: biomimetic crosslinking of silicones by phenolic coupling

Abstract: Phenolic compounds undergo radical coupling under oxidizing conditions. Silicone oils were modified with eugenol using hydrosilylation to create oils and elastomers that exhibited antioxidant activity due to the presence of...

Cited by 3 publications

References 32 publications

Functional silicone oils and elastomers: new routes lead to new properties

Functional silicone oils and elastomers: new routes lead to new properties

Siloxane-Functionalized Eugenol-Based Novolacs: from Facile Synthesis to Their Cured Bisphenol A Epoxy Thermosets with Superb Toughness and Thermal Stability

Phytochemicals from Bark Extracts and Their Applicability in the Synthesis of Thermosetting Polymers: An Overview

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