Effect of Oxygen Inhibition on the Kinetic Constants of the UV-Radical Photopolymerization of Diurethane Dimethacrylate/Photoinitiator Systems

Taki, Kentaro; Watanabe, Yoshihito; Itô, Hiroshi; Ohshima, Masahiro

doi:10.1021/ma402437q

Cited by 49 publications

(50 citation statements)

References 45 publications

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“…Indeed, different processes are known to affect the conversion-time evolution during FRP reaction, such as autoacceleration and deceleration [30][31][32] as well as termination by reaction diffusion. [30,[33][34][35][36][37][38][39][40][41][42][43][44][45] Taking into account these effects into a kinetic model requires to consider the change in the rate constants during the photopolymerization within a free radical photopolymerization model as described in the literature [46][47][48][49][50][51] and recently used to predict kinetic rate constants during dark polymerizations experiments under oxygen diffusion [52] and model layer-by-layer UVcuring. [53] Complete description of the model can be found in the Supporting Information.…”

Section: Kinetic Modeling Of Frp Initiated By a Triazine-based Type-imentioning

confidence: 99%

Triazine‐Based Type‐II Photoinitiating System for Free Radical Photopolymerization: Mechanism, Efficiency, and Modeling

Christmann

Allonas

Ley

et al. 2017

Macro Chemistry & Physics

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Isopropylthioxanthone, a versatile photoinitiator (PI) for free radical photopolymerization (FRP), is combined with a triazine derivative (Tz) in a Type-II photoinitiating system (PIS). Initiation ability of this system for acrylate photopolymerization is assessed using a diacrylate monomer. Involvement of a photoinduced electron transfer mechanism is demonstrated by time-resolved spectro scopic measurements. Further insights in this mechanism are obtained through the use of a photopolymerization kinetic model taking into account the main reaction steps from the absorption of photons to the formation of the polymer. Prediction ability of the model is also tested with different initial concentrations of PI and co-initiator, as well as a different Tz. This last experiment reveals the noticeable role of back electron transfer in the FRP mechanism of Type-II PIS. by the use of a photoinitiating system (PIS). It converts photons into chemical energy through the production of radicals capable of reacting with acrylic monomers to initiate macromolecular chains. Three main families of PIS have been developed, each with their own advantages and limitations. [2,[4][5][6][7][8][9] Type-I PIS rely on the photoinduced dissociation of the initiator to produce primary radicals. Despite a high quantum yield of radical production, typical bond dissociation energies require the use of UV lamps that are known to be harmful and to release ozone in the atmosphere. Therefore, Type-II PIS have been developed, which combine a photoinitiator (PI) able to absorb light and a co-initiator capable of reacting with the excited PI through hydrogen abstraction or electron transfer. Nevertheless, radical production is limited by the diffusion of the species into the viscous monomer medium and competition of the bimolecular reaction with PI deactivation pathways. In the case of hydrogen abstraction, hydrogenated PI radicals (PIH • , such as ketyl radicals) could also act as terminating agents and reduce final conversion. [10,11] Photocyclic initiating systems (PCIS) have then been developed in order to combine advantages of previous PIS, i.e.,

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Section: Kinetic Modeling Of Frp Initiated By a Triazine-based Type-imentioning

confidence: 99%

Triazine‐Based Type‐II Photoinitiating System for Free Radical Photopolymerization: Mechanism, Efficiency, and Modeling

Christmann

Allonas

Ley

et al. 2017

Macro Chemistry & Physics

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“…The absorbance at 812 cm -1 was therefore measured by FT-IR (VERTEX 70, Bruker-Optics, Germany) and an optical transmittance bench [9]. Conversion of the acrylate group was considered proportional to the absorbance when normalized by the film thickness.…”

Section: Conversion Of Uv-cured Resinmentioning

confidence: 99%

Effects of UV Intensity, Line-speed, and Light Distribution on Conversion and Surface Elastic Modulus of Roll-to-roll UV-cured Film

Taki

Kondo

Ito

2016

J. Photopol. Sci. Technol.

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Roll-to-roll UV nanoimprint lithography (R2RUVNIL) is a promising technology for fabricating nanostructures on flexible films, but its application requires finding feasible operating conditions to peel-off the UV resin from the mold. Furthermore, to achieve the required nanostructure, conversion of the UV resin needs to be precisely optimized in terms of the UV intensity and line speed. In this study, (1,6-bis(acryloyloxy)hexane) resin was cured by roll-to-roll UV-curing while monitoring its conversion and surface elasticity by Fourier transform infrared spectroscopy and a nano indenter, respectively. It was found that the conversion increases by up to 85% with a decrease in line speed and increase in UV intensity. The effect of varying the distribution of UV light on the roller mold was also investigated, which revealed that a sharp distribution of UV light is effective in increasing the surface elastic modulus from 0.2 to 1.0 GPa at 0.6 conversion.

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“…Moreover, the measured kinetic constants tend to change by the inhibition of oxygen and formation of cross-linking networks [9].…”

Section: Introductionmentioning

confidence: 98%

“…Numerical simulations of photopolymerization are a powerful technique for analyzing UV curing, which has been investigated by several researchers [2][3][4][5][6][7][8][9]. Numerical simulations can be categorized into two approaches based on monomer diffusion.…”

Section: Introductionmentioning

confidence: 99%

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Photopolymerization Kinetics of Different Chain Sizes of Bi-functional Acrylic Monomers using Real Time FT-IR

Taki

Taguchi

Hayashi

et al. 2016

J. Photopol. Sci. Technol.

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In this study, the photopolymerization kinetics of bifunctional acrylic monomers having different chain lengths, such as 1,4-bis(acryloyloxy)butane, 1,6-bis(acryloyloxy)hexane, and 1,10-bis(acryloyloxy)decane, was investigated by real-time Fourier transform infrared (FTIR) spectroscopy, using Irgacure 184 ® (1 wt%) as the photoinitiator. Dark polymerization analysis was employed for measuring the kinetic constants for propagation and termination. Plots of kinetic constants for propagation against double-bond conversion showed a plateau, suggesting that the reaction rate is controlled at low conversion, and with increasing conversion, the reaction rate decreases as the diffusion rate of the monomer controls propagation. At low conversion, as compared to the reaction for a monomer having a long chain length, the propagation reaction for a monomer with a short chain length switched to a diffusion-rate controlled propagation reaction. The results suggested that short chain length monomers form a dense cross-linking network, which hinders the diffusion of the monomer, and the kinetic constants decrease at low conversion. The results obtained from the plot of kinetic chain length versus conversion indicated that at a maximum kinetic chain length of up to 10 6 , the reaction switches to the diffusion-rate controlled propagation of each monomer.

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Effect of Oxygen Inhibition on the Kinetic Constants of the UV-Radical Photopolymerization of Diurethane Dimethacrylate/Photoinitiator Systems

Cited by 49 publications

References 45 publications

Triazine‐Based Type‐II Photoinitiating System for Free Radical Photopolymerization: Mechanism, Efficiency, and Modeling

Triazine‐Based Type‐II Photoinitiating System for Free Radical Photopolymerization: Mechanism, Efficiency, and Modeling

Effects of UV Intensity, Line-speed, and Light Distribution on Conversion and Surface Elastic Modulus of Roll-to-roll UV-cured Film

Photopolymerization Kinetics of Different Chain Sizes of Bi-functional Acrylic Monomers using Real Time FT-IR

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