共查询到20条相似文献,搜索用时 15 毫秒
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Koichi Kawamura Christian Ley Julien Schmitt Maxime Barnet Xavier Allonas 《Journal of polymer science. Part A, Polymer chemistry》2013,51(20):4325-4330
A new visible light photoinitiating system (PIS) containing a linked dye‐coinitiator dyad and a nondissociative electron donor was evaluated and compared with unlinked three components systems. Our results show that in the physical mixture of the three component PIS, addition of the nondissociative donor decreased the Rp to a great extent, whereas in combination with the dyads an increase in Rp is observed. The results were explained based on faster intramolecular electron transfer in linked pairs and point out the importance of linked initiator in three‐component PIS for the first time. This system is the first example of three‐components system with a nondissociative donor that would be useful for long life coating formulation. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4325–4330 相似文献
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Fang Gao Huayong Peng Long Yang Xiaojiao Liu Jianchao Wang Nvdan Hu Ting Xie Hongru Li Shengtao Zhang 《先进技术聚合物》2009,20(12):1010-1016
In this paper, we presented four novel visible light photoinitiating systems, which employed nitro‐stilbenzene derivatives as photoinitiators. Visible light photopolymerization of these systems was studied completely. The results showed that the chemical structures of the photoinitiators, photoinduced electron transfer approach, solvent polarity, and monomers played significant effects on the visible light photopolymerization. The electrochemistry of nitro‐stilbenzene was dramatically influenced by the linking benzophenone moiety. The cyclic voltammograms of four photoinitiators were determined and discussed. We further estimated the thermodriving force for electron transfer between nitro‐stilbenzene and benzophenone. Thermal stabilities of new photoinitators were determined by the analysis of differential scanning calorimetry (DSC) and thermogravimetry (TG) in this paper. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Pauline Carion Ahmad Ibrahim Xavier Allonas Cline Croutx‐Barghorn Gildas L'Hostis 《Journal of polymer science. Part A, Polymer chemistry》2019,57(8):898-906
Free‐radical photopolymerization is scarcely used for the manufacturing of fiber‐reinforced polymers. The main issue relies on the penetration depth of light which affects the conversion degree when photopolymerizing thick samples. Consequently, this could lead to inhomogeneous polymer properties. The ability of acylphosphine oxides to photobleach under near UV irradiation makes them of great interest for the curing of thick samples. Therefore, the influence of (2,4,6‐trimethylbenzoyl) phosphine oxide on the curing of composites under LED is investigated. Although that a frontal photopolymerization process can be evidenced, it was found that full photobleaching is hardly obtained at high concentration of photoinitiator. Six layers laminates made of unidirectional fiber glass and unsaturated polyester resin were prepared. The existence of an optimal range of concentration for which the conversion of the resin is the most homogeneous throughout its thickness was pointed out, a fact that is confirmed by dynamic mechanical analysis. Interestingly, this effect is reflected in the shrinkage of the resin as shown by direct measurements or deflection experiments. Mechanical analysis was undertaken whose results correlate well with the aforementioned study, demonstrating the occurrence of a balance between the concentration of photoinitiator and the mechanical properties of the samples. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 898–906 相似文献
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Dr. Joon Seok Lee Dong Heon Nam Su Keun Kuk Prof. Dr. Chan Beum Park 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(13):3584-3588
Artificial photosynthesis in nanobiocatalytic assemblies aims to reconstruct man‐made photosensitizers, electron mediators, electron donors, and redox enzymes for solar synthesis of valuable chemicals through photochemical cofactor regeneration. Herein, we report, for the first time, on nanobiocatalytic artificial photosynthesis in near‐infrared (NIR) light, which constitutes over 46% of the solar energy. For NIR‐light‐driven photoenzymatic synthesis, we synthesized silica‐coated upconversion nanoparticles, Si‐NaYF4:Yb,Er and Si‐NaYF4:Yb,Tm, for efficient photon‐conversion through Förster resonance energy transfer (FRET) with rose bengal (RB), a photosensitizer. We observed NIR‐induced electron transfer by using linear sweep voltammetric analysis; this indicates that photoexcited electrons of RB/Si‐NaYF4:Yb,Er are transferred to NAD+ through a Rh‐based electron mediator. RB/Si‐NaYF4:Yb,Er nanoparticles, which exhibit higher FRET efficiency due to more spectral overlap than RB/Si‐NaYF4:Yb,Tm, perform much better in the photoenzymatic conversion. 相似文献
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Mohamad El‐Roz Jacques Lalevée Fabrice Morlet‐Savary Xavier Allonas Jean Pierre Fouassier 《Journal of polymer science. Part A, Polymer chemistry》2008,46(22):7369-7375
New thiopyrylium and pyrylium salt‐based photoinitiating systems for visible light induced free radical polymerization (FRP) or free radical promoted cationic polymerization (FRPCP) under visible lights are presented. The reaction mechanisms are investigated by laser flash photolysis and the structure/reactivity trend is discussed. The abilities of two different classes of coinitiators are investigated (thiols/disulfides and silanes). In FRP, upon irradiation with a xenon lamp (λ > 390 nm), the (thio)pyrylium salts in combination with thiols or disulfides lead to very high polymerization rates, compared to the reference eosin Y/methyldiethanolamine system. In FRPCP, silanes are found much better coinitiators: a high efficiency of the photopolymerization under air is noted. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7369–7375, 2008 相似文献
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Andreas Mautner Xiaohua Qin Barbara Kapeller Guenter Russmueller Thomas Koch Juergen Stampfl Robert Liska 《Macromolecular rapid communications》2012,33(23):2046-2052
Vinyl carbonates have recently been identified as a suitable alternative to (meth)acrylates, especially due to the low irritancy and cytotoxicity of these monomers. The drawback of some vinyl carbonates containing abstractable hydrogens arises through their moderate reactivity compared with acrylates. Within this paper, we use the thiol‐ene concept to enhance the photoreactivity of vinyl carbonates to a large extent to reach the level of those of similar acrylates. Mechanical properties of the final thiol‐ene polymers were determined by nanoindentation. Furthermore, low toxicity of all components was confirmed by osteoblast cell culture experiments. 相似文献
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O. I. Tarzi X. Allonas C. Ley J.‐P. Fouassier 《Journal of polymer science. Part A, Polymer chemistry》2010,48(12):2594-2603
1,3,5,7,8‐pentamethyl pyrromethene difluoroborate complex (HMP) and 2,6‐diethyl‐8‐phenyl‐1,3,5,7‐tetramethylpyrromethene difluoroborate complex (EPP) were used to initiate the polymerization of a diacrylate in a two‐ and a three‐component photoinitiating system (PIS), together with an amine (ethyl‐4‐dimethylaminobenzoate, EDB) and triazine A (2‐(4‐methoxyphenyl)‐4,6‐bis(trichloromethyl)‐1,3,5‐triazine, TA) as coinitiators. For both pyrromethene dyes, the highest conversion was achieved with the three‐component PIS. As these dyes have high‐fluorescence quantum yields, steady state and time‐resolved techniques were used to study the possible fluorescence quenching by the amine and the triazine, as well as laser flash photolysis to investigate the electron transfer process that occurs in these PIS from either the singlet or triplet excited states. The electron transfer reaction is evidenced by using time‐resolved photoconductivity. Experiments show that the main interaction between the dye and both coinitiators is through its excited singlet state and the process is more efficient when TA is present. The beneficial effect noted when both coinitiators are used in a three‐component system is ascribed to secondary reactions between the coinitiators and intermediates that lead to the generation of higher amount of initiating species and the recovery of the initial dye. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2594–2603, 2010 相似文献
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T. Brian Cavitt Brian Phillips Charles E. Hoyle Bo Pan Sukhendu B. Hait Kalyanaraman Viswanathan Sonny Jnsson 《Journal of polymer science. Part A, Polymer chemistry》2004,42(16):4009-4015
Three‐component photoinitiators comprised of an N‐arylphthalimide, a diarylketone, and a tertiary amine were investigated for their initiation efficiency of acrylate polymerization. The use of an electron‐deficient N‐arylphthalimide resulted in a greater acrylate polymerization rate than an electron‐rich N‐arylphthalimide. Triplet energies of each N‐arylphthalimide, determined from their phosphorescence spectra, and the respective rate constants for triplet quenching by the N‐arylphthalimide derivatives (acquired via laser flash photolysis) indicated that an electron–proton transfer from an intermediate radical species to the N‐arylphthalimide (not energy transfer from triplet sensitization) is responsible for generating the initiating radicals under the conditions and species concentrations used for polymerization. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4009–4015, 2004 相似文献
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Naphthalimide‐phthalimide derivative based photoinitiating systems for polymerization reactions under blue lights 下载免费PDF全文
Pu Xiao Frédéric Dumur Jing Zhang Bernadette Graff Didier Gigmes Jean Pierre Fouassier Jacques Lalevée 《Journal of polymer science. Part A, Polymer chemistry》2015,53(5):665-674
Naphthalimide‐phthalimide derivatives (NDPDs) have been synthesized and combined with an iodonium salt, N‐vinylcarbazole, amine or 2,4,6‐tris(trichloromethyl)‐1,3,5‐triazine to produce reactive species (i.e., radicals and cations). These generated reactive species are capable of initiating the cationic polymerization of epoxides and/or the radical polymerization of acrylates upon exposure to very soft polychromatic visible lights or blue lights. Compared with the well‐known camphorquinone based systems used as references, the novel NDPD based combinations employed here demonstrate clearly higher efficiencies for the cationic polymerization of epoxides under air as well as the radical polymerization of acrylates. Remarkably, one of the NDPDs (i.e., NDPD2) based systems is characterized by an outstanding reactivity. The structure/reactivity/efficiency relationships of the investigated NDPDs were studied by fluorescence, cyclic voltammetry, laser flash photolysis, electron spin resonance spin trapping, and steady state photolysis techniques. The key parameters for their reactivity are provided. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 665–674 相似文献
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Jun Wei Hongyu Wang Jie Yin 《Journal of polymer science. Part A, Polymer chemistry》2007,45(4):576-587
A novel thio‐containing diamine with a benzophenone structure, 4‐amino‐4′‐[4‐aminothiophenyl]benzophenone (AATBP), was synthesized. Two kinds of polymeric photoinitiators, PUPIA and PUPI, were synthesized through the polycondensation of toluene‐2,4‐diisocyanate with AATBP and/or N‐methyldiethanolamine (MDEA). A macroamine, PUPA, was also synthesized for comparison. Fourier transform infrared, 1H NMR, and gel permeation chromatography analyses confirmed the structures of all the polymers. The ultraviolet–visible spectra of PUPIA, PUPI, and AATBP were similar, and all exhibited the maximal absorption above 325 nm. The photopolymerization of two monomers with different functionalities, poly(propylene glycol)diacrylate and trimethylolpropane triacrylate initiated by PUPIA, PUPI/MDEA, PUPI/PUPA, AATBP/MDEA, and AATBP/PUPA, was studied through differential scanning photocalorimetry. The results showed that both PUPIA and PUPI/MDEA had high photoefficiency, and their low‐molecular‐weight counterparts could hardly initiate the photopolymerization. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 576–587, 2007 相似文献
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Hongyu Wang Jun Wei Xuesong Jiang Jie Yin 《Journal of polymer science. Part A, Polymer chemistry》2006,44(12):3738-3750
In a continuation of research on chemically bonded photoinitiators comprising a structure of planar N‐phenylmaleimide (NPMI) and benzophenone (BP), a novel, highly efficient, polymerizable, sulfur‐containing photoinitiator, 4‐[(4‐maleimido)thiophenyl]benzophenone (MTPBP), was synthesized by the introduction of an NPMI group into BP. Another chemically bonded photoinitiator, 4‐[(4‐maleimido)phenoxy]benzophenone (MPBP), was selected to evaluate its photoefficiency. The results showed that MTPBP possessed a greatly redshifted UV maximal absorption and a very weak fluorescence emission. Electron spin resonance spectra indicated that the C? S bond in its molecule underwent photolysis reactions to generate radicals to initiate the polymerization. Three representative types of different functionality monomers—methyl methacrylate, 1,6‐hexanediol diacrylate, and trimethylolpropane triacrylate—were chosen to be initiated through dilatometry and differential scanning photocalorimetry with unsaturated tertiary amine N,N‐dimethylaminoethyl methacrylate as the coinitiator. The results showed surprisingly high efficiency of MTPBP due to the mutual influence between NPMI and BP as in their physical mixtures and photolysis reactions at the C? S bond. Both MPBP and MTPBP behaved with similar regularity toward different monomers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3738–3750, 2006 相似文献
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Highly Efficient Near‐Infrared Delayed Fluorescence Organic Light Emitting Diodes Using a Phenanthrene‐Based Charge‐Transfer Compound 下载免费PDF全文
Shipan Wang Xianju Yan Zong Cheng Prof. Dr. Hongyu Zhang Prof. Dr. Yu Liu Prof. Dr. Yue Wang 《Angewandte Chemie (International ed. in English)》2015,54(44):13068-13072
Significant efforts have been made to develop high‐efficiency organic light‐emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) emitters with blue, green, yellow, and orange–red colors. However, efficient TADF materials with colors ranging from red, to deep‐red, to near‐infrared (NIR) have been rarely reported owing to the difficulty in molecular design. Herein, we report the first NIR TADF molecule TPA‐DCPP (TPA=triphenylamine; DCPP=2,3‐dicyanopyrazino phenanthrene) which has a small singlet–triplet splitting (ΔEST) of 0.13 eV. Its nondoped OLED device exhibits a maximum external quantum efficiency (EQE) of 2.1 % with a Commission International de L′Éclairage (CIE) coordinate of (0.70, 0.29). Moreover, an extremely high EQE of nearly 10 % with an emission band at λ=668 nm has been achieved in the doped device, which is comparable to the most‐efficient deep‐red/NIR phosphorescent OLEDs with similar electroluminescent spectra. 相似文献
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Light‐induced controlled free radical polymerization of methacrylates using iron‐based photocatalyst in visible light 下载免费PDF全文
Ankushi Bansal Pawan Kumar Chandra D. Sharma Siddharth S. Ray Suman L. Jain 《Journal of polymer science. Part A, Polymer chemistry》2015,53(23):2739-2746
A novel visible light mediated catalytic system based on low cost iron complex, that is, Fe(bpy)3(PF)6 photocatalyst that initiates and control the free radical polymerization of methacrylates using ethyl α‐bromoisobutyrate (EBriB) as an initiator and 20 watt LED as light source is developed. The polymerization is initiated with turning the light on and immediately terminated by turning the light off. In addition, the molecular weight of polymer can be varied by changing the ratio of monomer and initiator. The merits of the present methodology lie in the use of low cost less precious, highly abundant iron‐based photocatalyst, avoidance of sacrificial donor and need of lower catalyst amount under visible light. The optimum amount of catalyst and initiator were established and successful polymerization of various methacrylates was achieved under the optimized polymerization conditions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2739–2746 相似文献
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Neil B. Cramer Sirish K. Reddy Hui Lu Tsali Cross Rishi Raj Christopher N. Bowman 《Journal of polymer science. Part A, Polymer chemistry》2004,42(7):1752-1757
The liquid, ceramic precursor monomer VL20 was copolymerized with a thiol monomer in a traditional radical thiol‐ene photopolymerization. Polymerization occurred via addition of the thiol functional group to the vinyl silazane functional group in a 1:1 ratio consistent with a step‐growth polymerization. Gelation occurred at a high conversion of functional groups (70%) consistent with an average molecular weight and functionality of 560 and 1.7, respectively, for VL20 monomers. Initiatorless photopolymerization of the thiol‐VL20 system also occurred upon irradiation at either 365 or 254 nm. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1752–1757, 2004 相似文献
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Idriss Bakas Gorkem Yilmaz Zouhair Ait‐Touchente Aazdine Lamouri Philippe Lang Nicolas Battaglini Benjamin Carbonnier Mohamed M. Chehimi Yusuf Yagci 《Journal of polymer science. Part A, Polymer chemistry》2016,54(21):3506-3515
The surface chemistry of aryl diazonium salts has progressed at a remarkable pace in the last two decades, and opened many avenues in materials science. These compounds are excellent coupling agents for polymers to surfaces via several surface‐confined polymerization methods. For the first time, we demonstrate that diazonium salts are efficient for surface initiating radical photopolymerization in the visible light of methyl methacrylate (MMA) and 2‐hydroxyethyl methacrylate (HEMA) taken as model monomers. To do so, 4‐(dimethylamino)benzenediazonium salt was electroreduced on gold plates or flexible ITO sheets to provide 4‐(dimethylamino)phenyl (DMA) hydrogen donor layers; while excited state camphorquinone acted as the free hydrogen abstractor. In the same way, we co‐polymerized HEMA and MMA with ethylene glycol dimethacrylate in order to obtain crosslinked polymer grafts. We demonstrate by XPS that gold was efficiently screened by the polymer layers and that the wettability of the surfaces accounts for the hydrophilic or hydrophobic characters of the tethered polymers. Homo‐ and crosslinked PMMA grafts were found to resist removal by the paint stripper methyl ethyl ketone. The grafted DMA/camphorquinone system operating in the visible light holds great promises in terms of adhesion of in situ designed continuous or patterned polymer coatings on various substrates. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3506–3515 相似文献