Lichtinitiierte polymer- und polymerisations-reaktionen XXII: Untersuchungen zur photolyse von photo-initiatoren mit benzyliden-tert.-butylamin-n-oxid als spin-trap

Baumann, H.; Timpe, H.‐J.; Zubarev, Valentin; Fok, N.V.; Melnikov, Mikhail Ya.

doi:10.1016/0047-2670(85)85065-6

Cited by 26 publications

(14 citation statements)

References 29 publications

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“…When using the AQD/DMBzOH system ( Figure 4A), only one speciesi so bservedw itht he following hyperfine coupling constants aN = 14.42 Ga nd aH = 2.0 G. The corresponding radical is assigned to ac arbon-centered radical [13] in the a positiont o the alcohol group in the DMBzOH skeleton. Indeed, an assumedo ne-step mechanism involving ah ydrogen abstraction reaction resultsi nt he correspondingD MBzOH derivedr adical.…”

Section: Mechanistic Approachmentioning

confidence: 99%

Photoinitiating Systems Based on Anthraquinone Derivatives: Synthesis of Antifouling and Biocide Coatings

et al. 2017

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Photoinitiating systems combining 2,6‐diaminoanthraquinone (AQD), iodonium salt (Iod), and benzyl alcohol derivatives have been developed to efficiently initiate the cationic polymerization of epoxy monomers upon light exposure. Electron spin resonance spin‐trapping (ESR ST) experiments, fluorescence investigations, and steady‐state photolysis have demonstrated that a dye‐sensitized reaction occurs between AQD and the benzyl alcohol derivatives through a hydrogen abstraction mechanism upon light illumination, followed by reduction of Iod. The in situ liberation of protic acids promotes the cationic photopolymerization of epoxy monomers concomitantly with hydrolysis and condensation of the reactive methoxysilanes of an organic–inorganic precursor, for example, 3‐glycidyloxypropyltrimethoxysilane (GPTMS). Nanoindentation experiments and scratch resistance tests proved that the resulting GPTMS coatings exhibit very good resistance to brittle fracture and excellent adherence to stainless‐steel substrates. Interestingly, antibacterial tests of the GPTMS coatings showed efficient antifouling and biocide properties against E. coli and S. aureus.

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Section: Mechanistic Approachmentioning

confidence: 99%

Photoinitiating Systems Based on Anthraquinone Derivatives: Synthesis of Antifouling and Biocide Coatings

et al. 2017

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“…[11,14,[16][17][18] This is due to the competition between the radical/ST addition and the radical recombination. The formed adduct R-ST Á may also be not stable enough for a correct ESR detection.…”

Section: Backgroundsmentioning

confidence: 99%

“…The HFS values (a N ¼ 14.25 G; a H ¼ 4.51 G, and a N ¼ 13.82; a H ¼ 15.09 for PBN and DMPO, respectively) are in excellent agreement with those previously reported for a benzoyl radical (a N ¼ 14.23 G; a H ¼ 4.52 G, and a N ¼ 13.99 G; a H ¼ 15.57G for PBN and DMPO, respectively). [11,17] Interestingly, the dimethoxybenzyl radical is not trapped, presumably because of its stabilized character. On the other side, a known methyl radical-DMPO adduct (a N ¼ 14.43 G; a H ¼ 21.58 G) is clearly detected as a minor product.…”

Section: (2)mentioning

confidence: 99%

“…For short‐lived radicals hardly accessible by CW‐ESR or TR‐ESR, this ESR‐ST technique is highly valuable since the persistent adducts are easily observed. Despite a widespread use in life sciences,9 very few studies using only phenyl N ‐ tert ‐butyl nitrone (PBN) as a spin trap (ST) have been devoted to PIs (examples concern 2,2′‐dimethoxyphenyl acetophenone, 2‐hydroxymethyl‐1‐phenylpropan‐1‐one, and benzoin ether derivatives) 11–13. In these previous works, the benzoyl radical was mainly observed.…”

Section: Introductionmentioning

confidence: 99%

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Electron Spin Resonance Spin Trapping Technique: Application to the Cleavage Process of Photoinitiators

Criqui

Lalevée

Allonas

et al. 2008

Macro Chemistry & Physics

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The cleavage of different photoinitiators (PIs) of polymerization is investigated by the ESR spin trapping using two different spin traps (STs): 5,5′‐dimethyl‐1‐pyrroline N‐oxide (DMPO) and phenyl N‐tert‐butyl nitrone (PBN). The hyperfine splitting constants for the different adducts are measured and provide a new set of data. These results show a difference of selectivity between the two (STs) and outline their complementarities.

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“…The initiation quantum yield of BDK was reported to be 0.52. [22][23][24][25] In Figure 6, the values of t i which were calculated from the oxygen solubilities are plotted vs. the experimental data from RT-FTIR spectroscopy which were taken from Figure 4. From the close correlation between the both sets of data it can be concluded that the decay of the induction period with increasing temperature is solely due to the decreasing oxygen solubility in the acrylate.…”

Section: Resultsmentioning

confidence: 99%

Temperature Dependence of the Oxygen Solubility in Acrylates and its Effect on the Induction Period in UV Photopolymerization

Scherzer

Langguth

2005

Macro Chemistry & Physics

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Summary: The influence of temperature on the kinetics of the UV photopolymerization of two diacrylates carried out under air was studied by real‐time FTIR‐ATR spectroscopy. In the temperature range up to 100 °C, the rate of polymerization obeys the Arrhenius law. The induction period was found to decrease with increasing temperature. It was shown that this decay is exclusively due to the decreasing solubility of oxygen in the acrylate. Moreover, from the induction period and the oxygen solubility, quantum yields of the α‐cleavage of some photoinitiators were estimated.Induction period calculated from the solubility of oxygen in TPGDA in comparison with experimental data from RT‐FTIR measurements.magnified imageInduction period calculated from the solubility of oxygen in TPGDA in comparison with experimental data from RT‐FTIR measurements.

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Lichtinitiierte polymer- und polymerisations-reaktionen XXII: Untersuchungen zur photolyse von photo-initiatoren mit benzyliden-tert.-butylamin-n-oxid als spin-trap

Cited by 26 publications

References 29 publications

Photoinitiating Systems Based on Anthraquinone Derivatives: Synthesis of Antifouling and Biocide Coatings

Photoinitiating Systems Based on Anthraquinone Derivatives: Synthesis of Antifouling and Biocide Coatings

Electron Spin Resonance Spin Trapping Technique: Application to the Cleavage Process of Photoinitiators

Temperature Dependence of the Oxygen Solubility in Acrylates and its Effect on the Induction Period in UV Photopolymerization

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