Carbazolyl α-diketones as novel photoinitiators in photopolymerization under LEDs

Ma, Xiaoyu; Cao, Ding; Hu, Xiaotong; Nie, Jun; Wang, Tao

doi:10.1016/j.porgcoat.2020.105651

Cited by 13 publications

(18 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is universally accepted that the cleavage of Norrish type I PIs occurs in triplet state; ,, therefore, employing the BDE of the triplet state to calculate the Δ H is more reasonable than that of the ground state. Similarly, the triplet-state energy ( E T ) was employed to calculate the Δ H .…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Methyl Benzoylformate Derivative Norrish Type I Photoinitiators for Deep-Layer Photocuring under Near-UV or Visible LED

Gao

Nie

et al. 2021

Macromolecules

Self Cite

View full text Add to dashboard Cite

We designed and prepared a series of methyl benzoylformate (MBF) derivatives Norrish type I photoinitiators (MBFs) for light-emitting diode (LED)-induced photopolymerization through computer simulation. The potential photolysis mechanism of MBFs under LED at 405 nm was explored by steady-state photolysis, nuclear magnetic resonance, and electron spin resonance. The as-synthesized photoinitiator dimethyl 1,4dibenzoylformate (DM-BD-F) can efficiently initiate free radical photopolymerization of acrylate monomers under LED irradiation at 405 nm. Moreover, we predicted well the photoinitiating capability of MBFs through the cleavage exothermy (ΔH) calculated by triplet bond dissociation energy (BDE) and triplet energy (E T ). Significantly, based on the weak absorption of MBFs at 405 nm, MBFs were successfully applied to deep-layer photocuring and the curing depth reached 6.5 cm after the irradiation of LED at 405 nm for 30 s. This research provides a new idea and efficient strategy for the molecular design of photoinitiators for deep-layer photocuring.

show abstract

Section: Resultsmentioning

confidence: 99%

“…A few Norrish type I PIs including acylphosphine oxides, − oxime esters, ,,− naphthalimide aryl sulfide derivatives, , and α-dicarbonyls − for LED-induced photopolymerization have been reported recently. However, they still have some drawbacks.…”

Section: Introductionmentioning

confidence: 99%

Methyl Benzoylformate Derivative Norrish Type I Photoinitiators for Deep-Layer Photocuring under Near-UV or Visible LED

Gao

Nie

et al. 2021

Macromolecules

Self Cite

View full text Add to dashboard Cite

show abstract

“…The radicals generated in the form of radical adducts with the spin trapping agent (phenyl- N -tert-butylnitrone (PBN)) can be detected when the PyBN/PBN solution is subjected to a 365 nm LED irradiation. The radical adducts are confirmed by the hyperfine coupling constants ( a N = 13.9 G, a H = 3.4 G) of the EPR experimental spectra, which are consistent with those reported in the literature …”

Section: Results and Discussionmentioning

confidence: 99%

“…The radical adducts are confirmed by the hyperfine coupling constants (a N = 13.9 G, a H = 3.4 G) of the EPR experimental spectra, which are consistent with those reported in the literature. 5 Based on the IR, NMR, and EPR data, a possible mechanism for inducing radical photopolymerization by PyBN is shown in Scheme S2. As compared, PyBN was consumed and new product was generated.…”

Section: Radical Photopolymerization Of Pybn/acrylatementioning

confidence: 99%

“…Photopolymerization is a popular technique for curing materials used in applications such as three-dimensional (3D) printing, adhesives, and coatings. − Photoinitiated photopolymerization affords advantages such as low temperature, no usage of harmful solvents, a rapid curing rate, and spatial control of polymerization compared to the features of thermal curing. Radical photopolymerization has attracted increasing attention to obtain products with 3D structures by different additive manufacturing techniques − such as layer-wise and volumetric methods. , The curing principle of radical photosensitive resins is similar. , Generally, the photosensitive resin used for radical photopolymerization is composed of monomers and a prepolymer containing CC double bonds as well as a photoinitiator and co-initiator that matches a specific light wavelength. , (Meth)acrylate resin is a commonly used photoactive material both in academic and practical applications that yields a good cross-linked polymer via radical polymerization. − …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Radical Photopolymerization Using 1,4-Dihydropyrrolo[3,2-b]pyrrole Derivatives Prepared via One-Pot Synthesis

Chen

Liu

et al. 2021

ACS Omega

View full text Add to dashboard Cite

Radical photopolymerization has attracted significant attention for manufacturing products with complicated structures. Herein, the synthesized 1,4-bis(4-bromophenyl)-2,5-bis(4-nitrophenyl)-1,4-dihydropyrrole[3,2-b]pyrrole (PyBN) is found to show varying photoactivity upon irradiation at different wavelengths. PyBN affords two main absorption bands, and its maximum absorption peak is at 462 nm, attributing to its strong intramolecular charge transfer property based on the donor–acceptor structure. It efficiently photoinitiates the radical photopolymerization of different (meth)acrylate materials under 365 and 395 nm LED irradiation. The highest double bond conversion of 99.86% is achieved for these materials. Under 470 nm LED, PyBN does not show molecular structure change from photolysis results as a result of intramolecular charge transfer. Therefore, PyBN shows wavelength-selective photoactivity with potential application in dual-wavelength volumetric additive manufacturing. A unique solid product is successfully fabricated using a 365 nm LED with co-irradiation of a 470 nm LED. Additionally, PyBN incorporating camphorquinone (CQ) as a two-component visible light photoinitiator system is investigated under 470 nm LED irradiation. As PyBN has a charge transfer activity at 470 nm, the combination with CQ exhibits a good synergistic interaction. Besides nitro-based PyBN, a methyl-based PyBC was prepared as a reference compound.

show abstract

Synthesis and properties of acyldiphenylphosphine oxides photoinitiators carrying triphenylamine or pyrene group for free radical photopolymerization

Luo

2023

J of Applied Polymer Sci

View full text Add to dashboard Cite

Two new photoinitiators of acyldiphenylphosphine oxides carrying triphenylamine (NHPO) or pyrene group (BHPO) were designed and synthesized with diphenylphosphine oxide reacting with 4‐(diphenylamino) benzaldehyde or 1‐pyrenecarboxaldehyde. The solubility of NHPO is about 13.7 wt% in TMPTA, which is higher than that of (2,4,6‐trimethylbenzoyl) diphenylphosphine oxide (TPO) (about 12.5 wt%). The UV–Vis spectrum of NHPO and BHPO revealed that their maximum absorption wavelengths have redshifted to 397 and 419 nm, respectively, with a molar extinction coefficient of around 19,057 and 24,257 M−1 cm−1, suggesting that they are likely to be effective photoinitiators when exposed to light from LEDs. According to real‐time Fourier transform infrared spectroscopies, the degree of double bond conversion of NHPO reached 65%, which was higher than that of TPO (about 45%), showing that NHPO had substantially better photoinitiated properties than TPO. Using steady‐state photolysis and electron spin resonance spin‐trapping studies, the photocuring mechanism was examined, and it was discovered that the NHPO and BHPO had produced two free radicals. Additionally, NHPO exhibited superior biocompatibility performance as demonstrated by cytotoxicity assays and had a low migration rate of only 0.23%, as determined by migration. As a result, NHPO might be utilized in coatings for food packaging.

show abstract

Carbazolyl α-diketones as novel photoinitiators in photopolymerization under LEDs

Cited by 13 publications

References 44 publications

Methyl Benzoylformate Derivative Norrish Type I Photoinitiators for Deep-Layer Photocuring under Near-UV or Visible LED

Methyl Benzoylformate Derivative Norrish Type I Photoinitiators for Deep-Layer Photocuring under Near-UV or Visible LED

Radical Photopolymerization Using 1,4-Dihydropyrrolo[3,2-b]pyrrole Derivatives Prepared via One-Pot Synthesis

Synthesis and properties of acyldiphenylphosphine oxides photoinitiators carrying triphenylamine or pyrene group for free radical photopolymerization

Contact Info

Product

Resources

About