Photopolymerization of acrylate resin and ceramic suspensions with benzylidene ketones under blue/green LED

European Polymer Journal

et al. 2021

In this study, light-emitting diodes (LEDs) used as secure, low-cost and possessing long emission wavelengths irradiation sources were applied in photopolymerization. Seven novel anthracene derivatives (noted A1-A7) have been proposed and evaluated in photosensitive systems for LED photopolymerization. Three final function conversions of epoxy using some anthracene/iodonium salt systems were even higher than the well-established dibutoxyanthracene (DBA)/iodonium salt benchmark system. In addition, due to the good light absorption properties, the cationic photopolymerization also was carried out in the presence of the chalconeanthracene/iodonium salt systems under LED@470 nm or laser diode@447 nm irradiation (not possible to do with the reference DBA systems). Remarkably, these derivatives were also able to sensitize sulfonium salts. The photochemical reactivity of anthracenes was investigated through steady state photolysis and fluorescence quenching experiments. Furthermore, the proposed interaction mechanisms of chalcone-anthracene derivatives and additives (iodonium salt and amine) were discussed using the free energy changes of electron transfer reactions. Interestingly, the cationic photopolymerization of A5/iodonium salt system was applied in 3D printing and the 3D patterns showed a good spatial resolution.

Section: Introductionmentioning

confidence: 99%

Design of photoinitiating systems based on the chalcone-anthracene scaffold for LED cationic photopolymerization and application in 3D printing

Liu

Zhang

European Polymer Journal

et al. 2021

“…Parallel to the red or NIR light-sensitive dye-based systems, FRPs can also be activated upon green light irradiation. 127 In previous publications, many researches have been focused on green light-sensitive dyes as photoinitiators for FRP (or cationic polymerization) under green light sources at 492-577 nm, especially at 520 nm. [128][129][130] Indeed, cationic polymerization upon green light irradiation is quite difficult, thus a majority of research is based on FRP.…”

Section: Green Light-sensitive Dyesmentioning

confidence: 99%

“…Benzylidene ketone derivatives can act as type II photoinitiators to initiate the FRP with an electron donor such as an amine. 127 Fu et al reported that two benzylidene ketones with D-π-A-π-D conjugated structures (abbrev. TPAK and CZK, marked as dyes 9 and 10 in Table 3, respectively) were used in two-component PISs with an amine (Triethanolamine [TTA]) under both irradiations of blue (460 nm)/green (520 nm) light sources.…”

Section: Benzylidene Ketone Derivativesmentioning

confidence: 99%

Organic dye‐based photoinitiating systems for visible‐light‐induced photopolymerization

Journal of Polymer Science

Xiao

Dumur

et al. 2021

Even though many organic dyes have been reported as photoinitiators/photosensitizers for free radical polymerization in the literature, the design and development of novel photoinitiating systems based on organic dyes adaptable for visible light irradiation, for example, 405 nm LED and sunlight still remains challenging. Recently, major achievements in the development of high‐performance photoinitiating systems based on organic dyes as light‐harvesting compounds and their uses as photoinitiators for photopolymerization under visible‐light irradiation have clearly emerged, giving rise to abundant literature. In this review, an overview of the recently synthesized chromophores belonging to various families of organic dyes and used as photoinitiators of polymerization during the 2018–2021 period are presented and classified. Recent works have resulted in the development of new chromophores exhibiting remarkable visible light absorption properties and excellent photoinitiation abilities upon irradiation with LEDs and/or sunlight in free radical photopolymerization processes. These developments notably indicate that sunlight has the advantages of being a cheap, unlimited, broad emission spectrum, and energy‐saving light source capable to be an efficient substitute to artificial light sources. The newly developed dye‐based photoinitiating systems designed to initiate visible‐light‐induced photopolymerization processes are likely to expand the scope of application of photopolymerization in modern sciences and technologies.

“…[4][5][6] Longer wavelengths have greater depth of penetration into both biological and synthetic materials, making them particularly attractive for biomedical applications. [7][8] Visible photopolymerization is greatly facilitated by the invention of blue LED that provides clean and efficient energy transformation. [9][10] On the other hand, chromophores that are able to efficiently absorb lower energy wavelengths for efficient initiation of photopolymerization has remained a challenge.…”

Section: Introductionmentioning

confidence: 99%

“…There has been a trend of replacing ultraviolet (UV) with visible and near‐infrared light 4–6 . Longer wavelengths have greater depth of penetration into both biological and synthetic materials, making them particularly attractive for biomedical applications 7–8 . Visible photopolymerization is greatly facilitated by the invention of blue LED that provides clean and efficient energy transformation 9–10 .…”

Section: Introductionmentioning

confidence: 99%

Photoinitiation mechanisms and photogelation kinetics of blue light induced polymerization of acrylamide with bicomponent photoinitiators

Journal of Polymer Science

Huang

et al. 2021

Blue light induced free radical photopolymerization of acrylamide (AM) was studied using five bicomponent photoinitiators, camphorquinon, riboflavin-5 0phosphate sodium, curcumin, eosin Y, and Ru(bpy) 3 Cl 2 (Ru(II)) as photosensitizer, and diphenyliodonium hexafluorophosphate or potassium persulfate as electron acceptor. Fluorescence and UV-vis spectroscopies were used in combination with molecular orbital computations to characterize the photochemical behaviors of the five bicomponent photoinitiators, explore the possible electron transfer pathways of the photoinitiation processes, and quantify photopolymerization efficiencies. Real-time photogelation behavior of poly(AM) was monitored by Photo-differential scanning calorimetry and photo-rheometry. Photogelation kinetic parameters, including dG 0 (storage modulus)/dt, dG 00 (loss modulus)/dt, time delay of gelation (t d), and duration of gelation (Δt gel), were derived from photorheological data analyses and used to identify the best bicomponent photoinitiator candidate for rapid fabrication of blue light induced photopolymerizable hydrogels for biomedical applications.