Cationic degradation of polysulfides and polyethers by chemical initiators and irradiation

Goethals, Eric J.; Meirvenne, Dirk Van; Clercq, Ronny De

doi:10.1002/masy.19880130114

Cited by 9 publications

(2 citation statements)

References 8 publications

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“…Among ferroceniums, Irgacure 261 i.e. (η 6 -(1-methylethyl)phenyl)(η 5 -cyclopentadienyl)iron hexafluorophosphate is a popular photoinitiator of cationic polymerization as this compound is commercially available [158][159][160][161][162][163][164]. However, the maximum absorption is centered at 241 nm and the absorption of Irgacure 261 extends from 200 to 300 nm so that this ferrocenium salt is a UV-centered photoinitiator.…”

Section: Carbazole-based Ferroceniummentioning

confidence: 99%

Recent advances on carbazole-based photoinitiators of polymerization

Dumur

2020

European Polymer Journal

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Photoinitiators of polymerization that can be activated under visible light and low intensity are actively researched as these compounds constitute the next generation of photoinitiators that will replace the controverted UV-photoinitiators. Over the years, a family of compounds has been identified as being highly promising in light of its remarkable photoinitiating ability, photochemical stability, low cost and easiness to functionalize, namely carbazoles. In this review, an overview of the different carbazole-based photoinitiators reported to date is presented. Interestingly, carbazoles have mostly been used as electron donors in push-pull structures, as photosensitizers for iodonium salts, as ligands for ferrocenium salts or as chromophores for phenacyl onium salts. These different applications clearly demonstrate the versatility of this structure used as the elemental building block for the design of UV, near-UV or visible light photoinitiators.

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Section: Carbazole-based Ferroceniummentioning

confidence: 99%

Recent advances on carbazole-based photoinitiators of polymerization

Dumur

2020

European Polymer Journal

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“…[56,[86][87] The cationic photopolymerization of thiiranes was reported for the first time in 2002, and choice of thiiranes instead of oxiranes was justified by the higher reactivity of these cycles during the ring-opening polymerization. [88] Comparison between di-(tertbutylphenyl)iodonium tetrafluoroborate, diphenyliodonium tetrafluoroborate, cyclopropyldiphenylsulfonium tetrafluoroborate and Irgacure 261 revealed the onium salt to initiate a faster polymerization process than Irgacure 261. Thus, while polymerizing CMT, final conversions of 95, 80 and 50% were respectively obtained with di-(tert-butylphenyl)iodonium tetrafluoroborate, cyclopropyl-diphenylsulfonium tetrafluoroborate and Irgacure 261 as photoinitiators after 60 minutes of irradiation with a mercury lamp (15 mW/cm²) of a 1,2dichloroethane solution under air containing 1 wt% of photoinitiators.…”

Section: Ferrocenium Salts Used As Photoinitiators Of Polymerization mentioning

confidence: 99%

Recent advances on iron-based photoinitiators of polymerization

Dumur

2020

European Polymer Journal

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With regards to the environmental and safety concerns raised nowadays by the polymer industry, polymerization processes requiring light as the activation source are currently knowing a revival of interest after decades of disinterest. Recent progresses in photopolymerization are notably sustained by the development of new polymerization application namely 3D and 4D printing enabling an unprecedented access to structures of incredible complexity. Parallel to the manufacturing process, the polymer material itself and its composition are also facing numerous questions concerning their environmental and human health impacts. Beyond the monomers, the different additives introduced in the resin can also be potentially toxic so that a great deal of efforts is currently done to develop new photoinitiators with a toxicity assessed as being insignificant. In this field, iron-based metal complexes are candidates of choice due to the clinical demonstration of their very low toxicities. Among iron complexes, ferrocene is among the most widely studied iron-based metallocene. Due to its unique and reversible electrochemical properties as well as their absorption centred in the visible range, numerous photoinitiators have been developed with ferrocene or its oxidized form i.e. ferrocenium. Parallel to this, the remarkable electrochemical properties of ferrocenium made it an excellent candidate for its incorporation in photoinitiating systems. However, interest for iron-based photoinitiators was not limited to ferrocene and ferrocenium, and Schiff base complexes were also successfully used as initiators of polymerization. In this review, an overview of the different iron-based photoinitiating systems reported to date is presented. More precisely, if iron-based photoinitiators are developed since 50 years, a special focus will be done on photoinitiators designed for recent polymerization conditions, namely, under visible light and low light intensity.

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Tailored polymers by cationic ring‐opening polymerizations: Scope and limitations based on mechanistic aspects

Goethals¹

1991

Makromolekulare Chemie. Macromolecular Symposia

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The main-and side-reactions which can occur during cationic ring-opening polymerizations of heterocyclic monomers are discussed. Based on these general reactions these polymerizations are classified into three groups.(1) Living (or "almost living") polymerizations provide the possibility to produce polymers with predictable molecular weight, narrow molecular weight distributions and having functional end groups (by initiation and/or end-capping).These polymerizations also allow the production of block and graft copolymers by sequential monomer additions. (2) Polymerizations which show temporary, i.e. reversible, termination reactions may be used to produce polymers with predictable molecular weights with molecular weight distributions of ~2 . Functional end groups may be introduced by end capping or chain transfer. These polymerizations generally lead to considerable fractions of cyclic oligomers. ( 3 ) Polymerizations which show irreversible termination reactions by the formation of stable, branched or (macro)cyclic onium ions. These polymerizations stop at limited conversions and are not suitable for the synthesis of well-defined polymers.

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Cationic degradation of polysulfides and polyethers by chemical initiators and irradiation

Cited by 9 publications

References 8 publications

Recent advances on carbazole-based photoinitiators of polymerization

Recent advances on carbazole-based photoinitiators of polymerization

Recent advances on iron-based photoinitiators of polymerization

Tailored polymers by cationic ring‐opening polymerizations: Scope and limitations based on mechanistic aspects

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