The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Marco Sangermano - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of polymeric microcapsules by interfacial-suspension cationic Photopolymerisation of divinyl ether monomer in aqueous suspension
Polymer Chemistry, 2017Co-Authors: Miriam Benedetti, Roberto Pisano, T. R. Congdon, S. P. Bassett, M. Alauhdin, Marco Sangermano, David M. Haddleton, Steven M Howdle, T. L. SchillerAbstract:Polymeric microcapusles have been synthesised with a markedly more hydrophillic monomer than previously reported, triethylene glycol divinyl ether, using cationic Photopolymerisation in an aqueous environment.
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In-situ graphene oxide reduction during UV-photopolymerization of graphene oxide/acrylic resins mixtures
Polymer (United Kingdom), 2012Co-Authors: Paola Fabbri, S. Bittolo Bon, Monica Montecchi, Dominique Foix, Luca Pasquali, Luca Valentini, Marco SangermanoAbstract:The preparation of electrically conductive acrylic resins containing reduced graphene oxide (rGO) by photopolymerization is presented. The synthesis consists of a single-step procedure starting from a homogeneous water dispersion of GO, which undergoes reduction induced by the UV radiation during the photopolymerization of an acrylic resin. The role played by the amount of radical photoinitiator added to the resin has been evaluated in relation to the in-situ reduction of GO, that was monitored by X-ray photoelectron spectroscopy. Results show that the UV-induced photopolymerization of acrylic resins with added GO gives rise to conductive acrylic composites thanks to the simultaneous reduction of GO to rGO and crosslinking of the resin. On this basis UV-induced photopolymerization is proposed as a sustainable strategy for the production of conductive graphene/polymer composites. ?? 2012 Elsevier Ltd. All rights reserved.
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Transparent and conductive graphene oxide/poly(ethylene glycol) diacrylate coatings obtained by photopolymerization
Macromolecular Materials and Engineering, 2011Co-Authors: Marco Sangermano, Sophie Marchi, Luca Valentini, S. Bittolo Bon, Paola FabbriAbstract:Water dispersed graphene oxide sheets were used to prepare graphene-polyethylenglycol diacrylate resin composites by photopolymerization. It was found that graphene sheets undergo excellent morphological distribution within the resin system, giving rise to transparent composites with unaltered thermal properties with respect to the neat resin, that are electrically conductive at loading ratios as low as 0.02 %wt of graphene oxide . The proposed strategy based on photopolymerization provides an easy, energy-saving and environmental friendly technique that can find a wide application in coating technology, mainly for electromagnetic shielding and antistatic coatings.
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Transparent and conductive graphene oxide-polyethylenglycol diacrylate coatings obtained by photopolymerization
No info, 2010Co-Authors: Marco Sangermano, Sophie Marchi, Luca Valentini, S. Bittolo Bon, Paola FabbriAbstract:Water dispersed graphene oxide sheets were used to prepare graphene-polyethylenglycol diacrylate resin composites by photopolymerization. It was found that graphene sheets undergo excellent morphological distribution within the resin system, giving rise to transparent composites with unaltered thermal properties with respect to the neat resin, that are electrically conductive at loading ratios as low as 0.02 %wt of graphene oxide . The proposed strategy based on photopolymerization provides an easy, energy-saving and environmental friendly technique that can find a wide application in coating technology, mainly for electromagnetic shielding and antistatic coatings.
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UV-cured nanostructured gold/acrylic coating
Macromolecular Materials and Engineering, 2008Co-Authors: Marco Sangermano, Andrea Marchino, S. Perruchas, Thierry Gacoin, Giancarlo RizzaAbstract:An aqueous dispersion of gold nanoparticles was added to an acrylic resin and UV-cured. The photopolymerization process was followed by means of real-time FT-IR spectroscopy. Nanostructured coatings containing a homogeneous dispersion of gold nanoparticles with an average size range of 20-25 nm were achieved. Macroscopic aggregation during polymerization was avoided due to the rapid initiation and kinetic associated with the photopolymerization technique, which allowed the medium to quickly solidify around the dispersion particles. 2008 WILEY-VCH Verlag GmbH Co. KGaA.
Neil R Cameron - One of the best experts on this subject based on the ideXlab platform.
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Fully biodegradable and biocompatible emulsion templated polymer scaffolds by thiol-acrylate polymerization of polycaprolactone macromonomers
Polymer Chemistry, 2015Co-Authors: D.w. Johnson, C. R. Langford, M. P. Didsbury, B. Lipp, S. A. Przyborski, Neil R CameronAbstract:Polycaprolactone triacrylate is used to make fully biodegradable and biocompatible tissue engineering scaffolds by emulsion templating and thiol-acrylate Photopolymerisation.
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Photopolymerised methacrylate-based emulsion-templated porous polymers
Reactive & Functional Polymers, 2012Co-Authors: Scott D. Kimmins, Paul Wyman, Neil R CameronAbstract:Abstract Highly porous and interconnected methacrylate-based porous materials were prepared by Photopolymerisation of the continuous phase of high internal phase emulsion (HIPE) templates. The rapid cure afforded by Photopolymerisation effectively ‘locks’ the emulsion morphology prior to emulsion destabilisation, in comparison to thermally-initiated HIPEs of similar compositions. Contrary to expectation, it was observed that fully cured photopolymerised polyHIPEs could be prepared with a thickness of up to 35 mm, despite the severe opacity of the parent emulsions. This is attributed to a photofrontal polymerisation process, where radicals generated on the surface propagate rapidly through the bulk of the emulsion. Homogeneous, well-defined polyHIPE materials of up to 95% nominal porosity were obtained by Photopolymerisation of HIPEs containing up to 30 vol.% glycidyl methacrylate (GMA) in the monomer phase (the remaining monomers and crosslinker are acrylates). Surprisingly, poly(ethylene glycol) methacrylate (PEG-MA), a nonionic monomer that is miscible with both emulsion phases, could be added to such HIPEs after preparation. On polymerisation, hydrophilic, water-wettable porous materials were obtained. Finally, it was also demonstrated that all-methacrylate HIPEs could be prepared and cured to yield GMA-containing polyHIPEs. These findings demonstrate the versatility of Photopolymerisation for the preparation of emulsion templated porous polymers.
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Photopolymerised methacrylate-based emulsion-templated porous polymers
Reactive and Functional Polymers, 2012Co-Authors: Scott D. Kimmins, Paul Wyman, Neil R CameronAbstract:Highly porous and interconnected methacrylate-based porous materials were prepared by Photopolymerisation of the continuous phase of high internal phase emulsion (HIPE) templates. The rapid cure afforded by Photopolymerisation effectively 'locks' the emulsion morphology prior to emulsion destabilisation, in comparison to thermally-initiated HIPEs of similar compositions. Contrary to expectation, it was observed that fully cured photopolymerised polyHIPEs could be prepared with a thickness of up to 35 mm, despite the severe opacity of the parent emulsions. This is attributed to a photofrontal polymerisation process, where radicals generated on the surface propagate rapidly through the bulk of the emulsion. Homogeneous, well-defined polyHIPE materials of up to 95% nominal porosity were obtained by Photopolymerisation of HIPEs containing up to 30 vol.% glycidyl methacrylate (GMA) in the monomer phase (the remaining monomers and crosslinker are acrylates). Surprisingly, poly(ethylene glycol) methacrylate (PEG-MA), a nonionic monomer that is miscible with both emulsion phases, could be added to such HIPEs after preparation. On polymerisation, hydrophilic, water-wettable porous materials were obtained. Finally, it was also demonstrated that all-methacrylate HIPEs could be prepared and cured to yield GMA-containing polyHIPEs. These findings demonstrate the versatility of Photopolymerisation for the preparation of emulsion templated porous polymers. © 2012 Elsevier Ltd. All rights reserved.
Jacques Lalevée - One of the best experts on this subject based on the ideXlab platform.
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N-Phenylglycine as a Versatile Photoinitiator under Near-UV LED
Macromolecules, 2018Co-Authors: J. Zhang, X. Mou, Bernadette Graff, Jacques Lalevée, Fabrice Morlet-savary, P. XiaoAbstract:© Copyright 2018 American Chemical Society. N-Phenylglycine is normally used as a co-initiator and can be photodecomposed by different dyes under UV or visible light irradiation to generate radicals for the initiation of free radical photopolymerization. However, the photochemistry and photoinitiation ability of N-phenylglycine alone upon exposure to near-UV light (e.g., UV LED at 392 nm), to the best of our knowledge, have not been investigated. In this research, the photochemistry of N-phenylglycine under the UV LED at 392 nm is studied using various approaches, and it reveals that radicals (PhNHCH 2 • ) can be produced from the direct photodecomposition of N-phenylglycine. In addition, N-phenylglycine can also interact with iodonium salt under the UV LED at 392 nm to generate phenyl radicals and cations. These formed active species exhibit high performance to initiate the free radical photopolymerization of acylates and cationic photopolymerization of epoxides and divinyl ethers.
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Organic Electronics: an El Dorado in the quest of new photoCatalysts as photoinitiators of polymerization
Accounts of Chemical Research, 2017Co-Authors: Frédéric Dumur, Jean-pierre Fouassier, Didier Gigmes, Jacques LalevéeAbstract:Photoinitiated polymerization has been the subject of continued research efforts due to the numerous applications in which this polymerization technique is involved (coatings, inks, adhesives, optoelectronic, laser imaging, stereolithography, nanotechnology, etc.). More recently, photopolymerization has received renewed interest due to the emergence of 3D-printing technologies. However, despite current academic and industrial interest in photopolymerization methodologies, a major limitation lies in the slow rates of photopolymerization. The development of new photoinitiating systems aimed at addressing this limitation is an active area of research. Photopolymerization occurs through the exposure of a curable formulation to light, generating radical and/or cationic species to initiate polymerization. At present, photopolymerization is facing numerous challenges related to safety, economic and ecological concerns. Furthermore, practical considerations such as the curing depth and the competition for light absorption between the chromophores and other species in the formulation are key parameters drastically affecting the photopolymerization process. To address these issues, photoinitiating systems operating under low intensity visible light irradiation, in the absence of solvents are highly sought after. In this context, the use of photoredox catalysis can be highly advantageous; that is, photoredox catalysts can provide high reactivities with low catalyst loading, permitting access to high performance photoinitiating systems. However, to act as efficient photoredox catalysts, specific criteria have to be fulfilled. A strong absorption over the visible range, an ability to easily oxidize or reduce as well as sufficient photochemical stability are basic prerequisites to make these molecules desirable candidates for photoredox catalysis. Considering the similarity of requirements between organic electronics and photopolymerization, numerous materials initially designed for applications in organic electronics have been revisited in the context of photopolymerization. Organic electronics is a branch of electronics and materials science focusing on the development of semiconductors devoted to three main research fields; organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), and organic solar cells (OSCs). The contribution of organic electronics to the field of electronics is important as it paves the way toward cheaper, lighter, and more energy efficient devices. In the present context of photopolymerization, materials that were investigated as photocatalysts were indifferently organic semiconductors used for transistors, charge-transport materials, and light-emitting materials used in electroluminescent devices or conjugated polymers and small molecule dyes for solar cells. In this Account, we summarize our latest developments in elaborating on photocatalytic systems based on these new classes of compounds. Through an in-depth understanding of the parameters governing their reactivities and our efforts to incorporate these materials into photoinitiating systems, we provide new knowledge and a valuable insight for future prospects.
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influence of zirconium propoxide on the radical induced Photopolymerisation of hybrid sol gel materials
New Journal of Chemistry, 2008Co-Authors: Davy Louis Versace, Jacques Lalevée, Olivier Soppera, Celine CroutxebarghornAbstract:This study emphasizes the role of zirconium propoxide on the free-radical Photopolymerisation of hybrid organic–inorganic material based on 3-methacryloxypropyltrimethoxysilane (MAPTMS). By means of atomic force microscopy in pulsed force mode and real-time Fourier-transform infrared spectroscopy, it is shown that the addition of zirconium complex in the hybrid sol–gel material leads to a well-polymerised and hydrophilic surface under UV-illumination. By contrast, sols without zirconium complex exhibit soft and sticky surfaces. The study also demonstrates an unexpected role of oxygen in the Photopolymerisation process. Indeed oxygen is well-known being a strong inhibitor of the radical polymerisation. However, in the present case, it interacts with Zr(OPr)4 and participates in a positive way to the photochemical process. During the irradiation, radicals react with O2 to form peroxyl radicals that are generally inert towards the Photopolymerisation. By using laser flash photolysis, it was proved that these radicals combine with zirconium propoxide to form new initiating species that contribute to further free-radical Photopolymerisation.
Mirek Macka - One of the best experts on this subject based on the ideXlab platform.
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UV-LED photopolymerised monoliths
Analyst, 2008Co-Authors: Silvija Abele, Fu Qiang Nie, František Foret, Brett Paull, Mirek MackaAbstract:For the first time Photopolymerisation of polymer monoliths has been realised with UV-light emitting diodes (LEDs) as light source and demonstrated with polymethacrylate monoliths created in fused silica capillaries and plastic chips.
Celine Croutxebarghorn - One of the best experts on this subject based on the ideXlab platform.
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influence of zirconium propoxide on the radical induced Photopolymerisation of hybrid sol gel materials
New Journal of Chemistry, 2008Co-Authors: Davy Louis Versace, Jacques Lalevée, Olivier Soppera, Celine CroutxebarghornAbstract:This study emphasizes the role of zirconium propoxide on the free-radical Photopolymerisation of hybrid organic–inorganic material based on 3-methacryloxypropyltrimethoxysilane (MAPTMS). By means of atomic force microscopy in pulsed force mode and real-time Fourier-transform infrared spectroscopy, it is shown that the addition of zirconium complex in the hybrid sol–gel material leads to a well-polymerised and hydrophilic surface under UV-illumination. By contrast, sols without zirconium complex exhibit soft and sticky surfaces. The study also demonstrates an unexpected role of oxygen in the Photopolymerisation process. Indeed oxygen is well-known being a strong inhibitor of the radical polymerisation. However, in the present case, it interacts with Zr(OPr)4 and participates in a positive way to the photochemical process. During the irradiation, radicals react with O2 to form peroxyl radicals that are generally inert towards the Photopolymerisation. By using laser flash photolysis, it was proved that these radicals combine with zirconium propoxide to form new initiating species that contribute to further free-radical Photopolymerisation.