Synthesis of silver/epoxy nanocomposites by visible light sensitization using highly conjugated thiophene derivatives

Yaǧcı, Yusuf; Sahin, Onur; Öztürk, Turan; Marchi, Sophie; Grassini, Sabrina; Sangermano, Marco

doi:10.1016/j.reactfunctpolym.2011.05.012

Cited by 44 publications

(35 citation statements)

References 37 publications

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“…They ensure good to excellent polymerizations are always obtained leading to tack free surface coatings after only 3 min. A concomitant increase of the band at 1080 cm is also observed due to the formation of the polyether network and polyacrylate, respectively (Figure 5B) [30][31][32]. A high Si-H consumption is also found in agreement with the proposed mechanisms (Schemes 1 and 2) ( Figure 5C).…”

Section: Dpsi/nvk/agsbf6 For the Synthesis Of Interpenetrated Polymersupporting

confidence: 75%

“…A quite good polymerization is always obtained at RT and under air leading to tack free surface coatings (gel time ~5 min and tack free time ~1 h). It is evident the important decrease of the typical epoxy band at 770-830 cm due to ether group formed during the ring-opening polymerization ( Figure 4B) [30][31][32][33][34][35][36][37]. Almost no inhibition is noted, as a short period is already requested for the solubilization of the silane into the formulation.…”

Section: Cationic Polymerization (Cp)mentioning

confidence: 98%

“…This approach consists of producing a radical R • (from an organosilane), to initiate FRP, that can be easily oxidized by a silver salt (e.g., AgSbF6) leading to R + , which corresponds to the ROP initiating structure (Scheme 2) [30][31][32] However, the nature of the primary radicals produced from the organosilane is crucial for getting a high polymerization efficiency, as they should be characterized by excellent oxidation properties; moreover, the resulting radicals and cations must be efficient structures for the FRP and CP reactions, respectively [33][34][35][36][37]. Even if a lot of systems have been developed in the last years [33][34][35][36][37][38][39][40][41][42], the search for novel additives being able to improve the radical and/or cationic polymerization processes still appears as a challenge.…”

Section: Introductionmentioning

confidence: 99%

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N-Vinylcarbazole: As an Additive for Thermal Polymerization at Room Temperature with in situ Formation of Ag(0) Nanoparticules

Tehfe¹,

Elkoun²,

Robert³

2015

Applied Sciences

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N-vinylcarbazole (NVK) is proposed as an additive for acrylates thermal free radical polymerization (FRP) and epoxy thermal ring opening polymerization (ROP) at room temperature. The new initiating systems are based on a silane/silver salt/N-vinylcarbazole interaction, which ensures good to excellent polymerization. Moreover, the polymerization is much more efficient under air than under argon. The effects of the N-vinylcarbazole, silane, silver salt and monomer structures are investigated. Interestingly, silver nanoparticles Ag(0) are formed in situ. The as-synthesized nanocomposite materials contained spherical nanoparticles homogeneously dispersed in the polymer matrices. Polymers and nanoparticles were characterized by Differential Scanning Calorimetry (DSC), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray Spectrometry (EDS), Fourier Transform Infrared Spectroscopy (FTIR), and UV-vis spectroscopy. A coherent picture of the involved chemical mechanisms is presented.

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Section: Dpsi/nvk/agsbf6 For the Synthesis Of Interpenetrated Polymersupporting

confidence: 75%

Section: Cationic Polymerization (Cp)mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

N-Vinylcarbazole: As an Additive for Thermal Polymerization at Room Temperature with in situ Formation of Ag(0) Nanoparticules

Tehfe¹,

Elkoun²,

Robert³

2015

Applied Sciences

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“…In our previous studies, we reported that several conjugated thiophene derivatives with extended conjugation can also act as electron-transfer photosensitizers in the near UV and visible regions for the photoinitiated cationic and free radical polymerization using onium salts. 37 Buckminster fullerene (C 60 ) exhibits excellent photochemical, superconducting, electrical, and magnetic properties due its aromatic-like character. 38−40 Each carbon atom of its skeleton is connected to the others by 3 σ-bonds and carries a single electron at the outer shell to yield highly conjugated π-bonds at the surface.…”

mentioning

confidence: 99%

Visible Light-Induced Cationic Polymerization Using Fullerenes

et al. 2012

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A novel visible light sensitive photoinitiator system for the cationic polymerization of typical monomers, for example, of oxiranes, such as cyclohexene oxide, vinyl ethers, such as iso-butyl vinyl ether, and other vinyl monomers, such as N-vinylcarbazole, using fullerene derivatives is described. The cationic polymerization of these monomers was initiated at room temperature upon irradiation in the visible region (λ inc > 400 nm) in bulk or chlorobenzene solutions with polystyrene-C 60 (PS-C 60 ) adduct or bare C 60 , respectively, in the presence of oxidizing salts such as silver hexafluorophosphate (AgPF 6 ) and diphenyliodonium hexafluorophosphate (Ph 2 I + PF 6 − ). A feasible mechanism, as correlated with optical absorption measurements, free energy changes (ΔG), and proton scavenging studies, involves formation of exciplex by the absorption of light in the first step. Subsequent electron transfer from excited C 60 or PS-C 60 to oxidizing salt yields radical cations of the fullerene derivatives. Both radical cations and a strong Brønsted acid derived by hydrogen abstraction initiate the cationic polymerization of a variety of monomers. S olar energy is the basis of all natural chemistry. In nature, a variety of electron transfer reactions such as photosynthesis are promoted by visible light. 1,2 Artificially, many organic reactions are also driven by solar energy, affording important advantages meeting the actual objectives of green chemistry. 3−7 The most common organic and polymeric compounds are transparent in the visible region (400−800 nm), which accounts for about 43% of the incoming solar spectrum. As a result, there has been great interest in developing soluble and processable organic and polymer-based catalysts absorbing efficiently in the visible region of the spectrum. 8−13 Photoinitiated polymerization is a well-known technique exploited in many industrially important areas. 14 Both free radical and cationic polymerizations have been used, and the mechanisms of initiation have been studied in detail. 15−24 The free radical mode is in a more advanced state due to not only its applicability to a wide range of monomers but also availability of photoinitiators with a broad spectral sensitivity, including the visible range. 22,25,26 Such photoinitiators are widely used in many targeted applications such as dental filling materials, photoresists, printing plates, integrated circuits, laser-induced 3D curing, holographic recordings, and nanoscale micromechanics. The most prominent cationic photoinitiators are iodonium 27 and sulphonium salts, 28 which absorb the light in the far and mid-UV regions. Extension of the spectral sensitivity of cationic polymerization to near UV and visible ranges is realized by the activation with light-sensitive additives, which do not directly initiate the polymerization. 29,30 Three different modes can be distinguished to externally stimulate the activity of the onium salts in the visible range: (i) oxidation of free radicals by onium salts (also called free radical pr...

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“…Besides, we cannot neglect the action of DMF [43] and pyrene chromophore to operate under these conditions as an electron-transfer photosensitizer for silver ions, in agreement with the data collected on the thiophene derivatives used in situ preparation of silver/nanocomposites. [44] Surprisingly, the UV spectra of poly(VAc-coAcrBzA)-Py solution/silver NPs (not shown) revealed no UV-induced changes due to silver plasmon resonance. Applying irradiation to the same solution but without polymer, the existence of plasmon band developed in the 350-450 nm region was indeed observed, when a deposition of metallic particles occurs onto the glass walls.…”

Section: Effect Of the In Situ Photogenerated Nanosilver Particlesmentioning

confidence: 90%

Preparation and characterization of novel p-acryloyloxybenzaldehyde copolymers bearing pyrene or fluorescein moieties. Interaction of fluorophore with some quenchers and silver nanoparticles

Buruiana¹,

Podasca²,

Buruiană³

2013

Designed Monomers and Polymers

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Two photopolymers, poly(vinyl acetate-co-p-acryloyloxybenzilideneiminepyrene) poly(VAc-co-AcrBzA)-Py and poly (vinyl acetate-co-p-acryloyloxybenzilideniminefluorescein) poly(VAc-co-AcrBzA)-Fl with pyrene and fluorescein in structure, have been prepared by chemical modification of the parent copolymer prior obtained through classical radical copolymerization. The structures of the polymers were characterized by FTIR, 1 H ( 13 C) NMR, UV, differential scanning calorimetry and thermogravimetric analysis, and gel permeation chromatography. The fluorescence properties of the photopolymers were investigated in dimethylformamide solutions containing various quenching agents (nitrobenzene, nitrophenol, p-nitrotoluene, picric acid, tetracyanoquinodimethane, Co 2+ , Hg 2+ , [UO 2 ] 2+ , NaOH, and HCl), the quenching efficiency varying in the next order: picric acid > TCNQ > p-nitrotoluene > nitrophenol. Quenching the fluorescence of fluoresceinimine occured only in acid medium (pH: 7.3-2.5) due to the protonated nitrogen, whereas with increasing basic pH (pH: 7.3-9.7) the fluorescence increased. Besides, fluorescence quenching or enhancement of fluorescence by silver nanoparticles (NPs) in situ photogenerated was investigated, our observations suggesting the role of polymer structure in stabilizing metal NPs in thin films.

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Synthesis of silver/epoxy nanocomposites by visible light sensitization using highly conjugated thiophene derivatives

Cited by 44 publications

References 37 publications

N-Vinylcarbazole: As an Additive for Thermal Polymerization at Room Temperature with in situ Formation of Ag(0) Nanoparticules

N-Vinylcarbazole: As an Additive for Thermal Polymerization at Room Temperature with in situ Formation of Ag(0) Nanoparticules

Visible Light-Induced Cationic Polymerization Using Fullerenes

Preparation and characterization of novel p-acryloyloxybenzaldehyde copolymers bearing pyrene or fluorescein moieties. Interaction of fluorophore with some quenchers and silver nanoparticles

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