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Malik MS, Wolfahrt M, Schlögl S. Redox cationic frontal polymerization: a new strategy towards fast and efficient curing of defect-free fiber reinforced polymer composites. RSC Adv 2023; 13:28993-29003. [PMID: 37799301 PMCID: PMC10548789 DOI: 10.1039/d3ra05976f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 09/25/2023] [Indexed: 10/07/2023] Open
Abstract
Frontal polymerization of epoxy-based thermosets is a promising curing technique for the production of carbon fiber reinforced composites (CFRCs). It exploits the exothermicity of polymerization reactions to convert liquid monomers to a solid 3D network. A self-sustaining curing reaction is triggered by heat or UV-radiation, resulting in a localized thermal reaction zone that propagates through the resin formulation. To date, frontal polymerization is limited to CFRCs with a low fiber volume percent as heat losses compromise on the propagation of the heat front, which is crucial for this autocatalytic curing mechanism. In addition, the choice of suitable epoxy monomers and thermal radical initiators is limited, as highly reactive cycloaliphatic epoxies as well as peroxides decarboxylate during radical induced cationic frontal polymerization. The resulting networks suffer from high defect rates and inferior mechanical properties. Herein, we overcome these shortcomings by introducing redox cationic frontal polymerization (RCFP) as a new frontal curing concept. In the first part of this study, the influence of stannous octoate (reducing agent) was studied on a frontally cured bisphenol A diglycidyl ether resin and mechanical and thermal properties were compared to a conventional anhydride cured counterpart. In a subsequent step, a quasi-isotropic CFRC with a fiber volume of >50 vol%, was successfully cured via RCFP. The composite exhibited a glass transition temperature > 100 °C and a low number of defects. Finally, it was demonstrated that the redox agent effectively prevents decarboxylation during frontal polymerization of a cycloaliphatic epoxy, demonstrating the versatility of RCFP in future applications.
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Affiliation(s)
| | - Markus Wolfahrt
- Polymer Competence Center Leoben Rossegerstraße 12 8700 Leoben Austria
| | - Sandra Schlögl
- Polymer Competence Center Leoben Rossegerstraße 12 8700 Leoben Austria
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Abstract
ConspectusHypervalent iodine reagents find application as selective chemical oxidants in a diverse array of oxidative transformations. The utility of these reagents is often ascribed to (1) the proclivity to engage being selective two-electron redox transformations; (2) facile ligand exchange at the three-centered, four-electron (3c-4e) hypervalent iodine-ligand (I-X) bonds; and (3) the hypernucleofugacity of aryl iodides. One-electron redox and iodine radical chemistry is well-precedented in the context of inorganic hypervalent iodine chemistry─for example, in the iodide-triiodide couple that drives dye-sensitized solar cells. In contrast, organic hypervalent iodine chemistry has historically been dominated by the two-electron I(I)/I(III) and I(III)/I(V) redox couples, which results from intrinsic instability of the intervening odd-electron species. Transient iodanyl radicals (i.e., formally I(II) species), generated by reductive activation of hypervalent I-X bonds, have recently gained attention as potential intermediates in hypervalent iodine chemistry. Importantly, these open-shell intermediates are typically generated by activation of stoichiometric hypervalent iodine reagents, and the role of the iodanyl radical in substrate functionalization and catalysis is largely unknown.Our group has been interested in advancing the chemistry of iodanyl radicals as intermediates in the sustainable synthesis of hypervalent I(III) and I(V) compounds and as novel platforms for substrate activation at open-shell main-group intermediates. In 2018, we disclosed the first example of aerobic hypervalent iodine catalysis by intercepting reactive intermediates in aldehyde autoxidation chemistry. While we initially hypothesized that the observed oxidation was accomplished by aerobically generated peracids via a two-electron I(I)-to-I(III) oxidation reaction, detailed mechanistic studies revealed the critical role of acetate-stabilized iodanyl radical intermediates. We subsequently leveraged these mechanistic insights to develop hypervalent iodine electrocatalysis. Our studies resulted in the identification of new catalyst design principles that give rise to highly efficient organoiodide electrocatalysts that operate at modest applied potentials. These advances addressed classical challenges in hypervalent iodine electrocatalysis related to the need for high applied potentials and high catalyst loadings. In some cases, we were able to isolate the anodically generated iodanyl radical intermediates, which allowed direct interrogation of the elementary chemical reactions characteristic of iodanyl radicals. Both substrate activation via bidirectional proton-coupled electron transfer (PCET) reactions at I(II) intermediates and disproportionation reactions of I(II) species to generate I(III) compounds have been experimentally validated.This Account discusses the emerging synthetic and catalytic chemistry of iodanyl radicals. Results from our group have demonstrated that these open-shell species can play a critical role in sustainable synthesis of hypervalent iodine reagents and play a heretofore unappreciated role in catalysis. Realization of I(I)/I(II) catalytic cycles as a mechanistic alternative to canonical two-electron iodine redox chemistry promises to open new avenues to application of organoiodides in catalysis.
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Affiliation(s)
- Asim Maity
- Texas A&M University, College Station, Texas 77843, United States
| | - Brandon L. Frey
- Texas A&M University, College Station, Texas 77843, United States
| | - David C. Powers
- Texas A&M University, College Station, Texas 77843, United States
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Moon HW, Cornella J. Bismuth Redox Catalysis: An Emerging Main-Group Platform for Organic Synthesis. ACS Catal 2022; 12:1382-1393. [PMID: 35096470 PMCID: PMC8787757 DOI: 10.1021/acscatal.1c04897] [Citation(s) in RCA: 68] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/09/2021] [Indexed: 12/11/2022]
Abstract
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Bismuth has recently
been shown to be able to maneuver between
different oxidation states, enabling access to unique redox cycles
that can be harnessed in the context of organic synthesis. Indeed,
various catalytic Bi redox platforms have been discovered and revealed
emerging opportunities in the field of main group redox catalysis.
The goal of this perspective is to provide an overview of the synthetic
methodologies that have been developed to date, which capitalize on
the Bi redox cycling. Recent catalytic methods via low-valent Bi(II)/Bi(III),
Bi(I)/Bi(III), and high-valent Bi(III)/Bi(V) redox couples are covered
as well as their underlying mechanisms and key intermediates. In addition,
we illustrate different design strategies stabilizing low-valent and
high-valent bismuth species, and highlight the characteristic reactivity
of bismuth complexes, compared to the lighter p-block
and d-block elements. Although it is not redox catalysis
in nature, we also discuss a recent example of non-Lewis acid, redox-neutral
Bi(III) catalysis proceeding through catalytic organometallic steps.
We close by discussing opportunities and future directions in this
emerging field of catalysis. We hope that this Perspective will provide
synthetic chemists with guiding principles for the future development
of catalytic transformations employing bismuth.
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Affiliation(s)
- Hye Won Moon
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr, 45470, Germany
| | - Josep Cornella
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr, 45470, Germany
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Sathissarat JH, Chu L, Danso R, Rawls HR, Whang K. Development of a difunctional oxirane and multifunctional acrylate interpenetrating polymer network composite system with antimicrobial properties. J Appl Polym Sci 2021. [DOI: 10.1002/app.50773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Lianrui Chu
- Department of Developmental Dentistry the University of Texas Health Science Center at San Antonio San Antonio Texas USA
| | - Robert Danso
- Department of Comprehensive Dentistry the University of Texas Health Science Center at San Antonio San Antonio Texas USA
| | - H. Ralph Rawls
- Department of Comprehensive Dentistry the University of Texas Health Science Center at San Antonio San Antonio Texas USA
| | - Kyumin Whang
- Department of Comprehensive Dentistry the University of Texas Health Science Center at San Antonio San Antonio Texas USA
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Dumur F. Recent advances on visible light photoinitiators of polymerization based on Indane-1,3-dione and related derivatives. Eur Polym J 2021. [DOI: 10.1016/j.eurpolymj.2020.110178] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Lim S, Radosevich AT. Round-Trip Oxidative Addition, Ligand Metathesis, and Reductive Elimination in a PIII/PV Synthetic Cycle. J Am Chem Soc 2020; 142:16188-16193. [DOI: 10.1021/jacs.0c07580] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Soohyun Lim
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Alexander T. Radosevich
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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7
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Redox two-component initiated free radical and cationic polymerizations: Concepts, reactions and applications. Prog Polym Sci 2019. [DOI: 10.1016/j.progpolymsci.2019.04.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Kloberg MJ, Helbich T, Rieger B. Silicon nanosheets as co-initiators for diaryliodonium induced radical and cationic polymerization. NANOTECHNOLOGY 2019; 30:075602. [PMID: 30523955 DOI: 10.1088/1361-6528/aaf3f2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A system of silicon nanosheets and a diaryliodonium salt was found to initiate cationic and radical polymerizations. The polymerization relies on a syngergistic interaction between the silicon nanomaterial and the diaryliodonium salt, whereby the silicon nanomaterial acts as a co-initiator, inducing the decomposition of the diaryliodonium salt. The decomposition products, in turn, are able to initiate both cationic and radical polymerizations thereby enabling a mild and straightforward reaction procedure to obtain a variety of polymer/nanomaterial composites with cationically and radically polymerizable monomers. Most importantly, this work highlights the potential of using silicon nanomaterials' unique properties not just for physical applications, but also in chemical applications.
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Affiliation(s)
- Marc Julian Kloberg
- WACKER-Chair of Macromolecular Chemistry, Lichtenbergstraße 4, D-85747, Germany. Catalysis Research Center, Ernst-Otto-Fischer Straße 2, D-85747, Germany
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Asandei AD. Photomediated Controlled Radical Polymerization and Block Copolymerization of Vinylidene Fluoride. Chem Rev 2016; 116:2244-74. [PMID: 26760676 DOI: 10.1021/acs.chemrev.5b00539] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This review summarizes recent research on novel photochemical methods for the initiation and control of the polymerization of main chain fluorinated monomers as exemplified by vinylidene fluoride (VDF) and for the synthesis of their block copolymers. Such reactions can be carried out at ambient temperature in glass tubes using visible light. Novel, original protocols include the use of hypervalent iodide carboxylates alone or in conjunction with molecular iodine, as well as the use of photoactive transition metal carbonyls in the presence of alkyl, fluoroalkyl, and perfluoroalkyl halides. An in-depth study of the reaction parameters highlights the use of dimethyl carbonate as a preferred polymerization solvent and outlines the structure-property relationship for hypervalent iodide carboxylates and halide initiators in both the free radical and iodine degenerative transfer controlled radical polymerization (IDT-CRP) of VDF. Finally, the rational selection of metal carbonyls that are successful not only as IDT mediators but, more importantly, in the quantitative activation of both PVDF-CH2-CF2-I and PVDF-CF2-CH2-I chain ends toward the synthesis of well-defined PVDF block copolymers is presented.
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Affiliation(s)
- Alexandru D Asandei
- Institute of Materials Science and Department of Chemistry University of Connecticut , 97 North Eagleville Road, Storrs, Connecticut 06269-3139, United States
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Zhu DY, Rong MZ, Zhang MQ. Self-healing polymeric materials based on microencapsulated healing agents: From design to preparation. Prog Polym Sci 2015. [DOI: 10.1016/j.progpolymsci.2015.07.002] [Citation(s) in RCA: 248] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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N-Vinylcarbazole: As an Additive for Thermal Polymerization at Room Temperature with in situ Formation of Ag(0) Nanoparticules. APPLIED SCIENCES-BASEL 2015. [DOI: 10.3390/app5030241] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Tehfe MA, Jamois R, Cousin P, Elkoun S, Robert M. In situ synthesis and characterization of silver/polymer nanocomposites by thermal cationic polymerization processes at room temperature: initiating systems based on organosilanes and starch nanocrystals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4305-4313. [PMID: 25793620 DOI: 10.1021/la504518c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
New methods for the preparation of silver nanoparticles/polymer nanocomposite materials by thermal cationic polymerization of ε-caprolactone (ε-CL) or α-pinene oxide (α-PO) at room temperature (RT) and under air were developed. The new initiating systems were based on silanes (Si), starch nanocrystals (StN) and metal salts. Excellent polymerization profiles were revealed. It was shown that silver nanoparticles (Ag(0) NPs) were in situ formed and that the addition of StN improves the polymerization efficiency. The as-synthesized nanocomposite materials contained spherical nanoparticles homogeneously dispersed in the polymer matrices. Polymers and nanoparticles were characterized by gel permeation chromatography (GPC), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy. A coherent picture of the involved chemical mechanisms is presented.
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Affiliation(s)
- Mohamad-Ali Tehfe
- Carrefour of Innovative Technology and Ecodesign (CITE), Faculty of Engineering, University of Sherbrooke, 2500 blvd Université, Sherbrooke, Quebec J1K 2C3, Canada
| | - Romain Jamois
- Carrefour of Innovative Technology and Ecodesign (CITE), Faculty of Engineering, University of Sherbrooke, 2500 blvd Université, Sherbrooke, Quebec J1K 2C3, Canada
| | - Patrice Cousin
- Carrefour of Innovative Technology and Ecodesign (CITE), Faculty of Engineering, University of Sherbrooke, 2500 blvd Université, Sherbrooke, Quebec J1K 2C3, Canada
| | - Saïd Elkoun
- Carrefour of Innovative Technology and Ecodesign (CITE), Faculty of Engineering, University of Sherbrooke, 2500 blvd Université, Sherbrooke, Quebec J1K 2C3, Canada
| | - Mathieu Robert
- Carrefour of Innovative Technology and Ecodesign (CITE), Faculty of Engineering, University of Sherbrooke, 2500 blvd Université, Sherbrooke, Quebec J1K 2C3, Canada
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Telitel S, Dumur F, Kavalli T, Graff B, Morlet-Savary F, Gigmes D, Fouassier JP, Lalevée J. The 1,3-bis(dicyanomethylidene)indane skeleton as a (photo) initiator in thermal ring opening polymerization at RT and radical or cationic photopolymerization. RSC Adv 2014. [DOI: 10.1039/c3ra42819b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Ye XJ, Zhang JL, Zhu Y, Rong MZ, Zhang MQ, Song YX, Zhang HX. Ultrafast self-healing of polymer toward strength restoration. ACS APPLIED MATERIALS & INTERFACES 2014; 6:3661-3670. [PMID: 24521220 DOI: 10.1021/am405989b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Self-healing materials should take effect immediately following crack generation in principle, but the speed of autonomic recovery of mechanical properties through either extrinsic or intrinsic healing strategy reported so far is not that fast. Mostly, a couple of hours are taken for reaching steady state or maximum healing. To accelerate the healing process, the authors of this work make use of antimony pentafluoride as instant hardener of epoxy and successfully encapsulate the highly active antimony pentafluoride-ethanol complex in terms of hollow silica spheres. Accordingly, self-healing agent based on microencapsulated antimony pentafluoride-ethanol complex and epoxy monomer is developed. Epoxy material with the embedded healant capsules can thus be healed within a few seconds, as demonstrated by impact and fatigue tests. It is believed that the outcome presented here might help to move the self-healing technique closer to practical application, especially when the engineering significance of epoxy material is concerned.
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Affiliation(s)
- Xiao Ji Ye
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, GD HPPC Lab, School of Chemistry and Chemical Engineering, Sun Yat-Sen University , Guangzhou 510275, P. R. China
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Lalevée J, Blanchard N, Tehfe MA, Chany AC, Fouassier JP. New boryl radicals derived from N-heteroaryl boranes: generation and reactivity. Chemistry 2011; 16:12920-7. [PMID: 20878804 DOI: 10.1002/chem.201001440] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Recently, boryl radicals have been the subject of revived interest. These structures were generated by hydrogen-abstraction reactions from the corresponding boranes (i.e., from amine or phosphine boranes). However, the classical issue remains their high B--H bond-dissociation energy (BDE), thereby preventing a very efficient hydrogen-abstraction process. In the present paper, new N-heteroaryl boranes that exhibiting low B--H BDE are presented; excellent hydrogen-transfer properties have been found. Both the generation and the reactivity of the associated boryl radicals have been investigated through their direct observation in laser flash photolysis. The boryl radical interactions with double bonds, oxygen, oxidizing agent, and alkyl halides have been studied. Some selected applications of N-heteroaryl boryl radicals as new polymerization-initiating structures are proposed to evidence their high intrinsic reactivity.
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Affiliation(s)
- Jacques Lalevée
- Department of Photochemistry, UMR CNRS 7525, University of Haute Alsace, ENSCMu, 3 rue Alfred Werner, 68093 Mulhouse Cedex, France.
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Crivello JV, Lee JL. Redox initiated cationic polymerization: Silane-N-aryl heteroaromatic onium salt redox couples. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/pola.24239] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Souane R, Tehfe MA, Lalevée J, Gigmes D, Fouassier JP. New Initiating Systems for Thermal Cationic Polymerization at Ambient Temperature with in situ Formation of Ag(0) Nanoparticles: A Silane/Silver Salt Combination. MACROMOL CHEM PHYS 2010. [DOI: 10.1002/macp.201000002] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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